La hauteur de la vue du recycleur imbriqué n'enveloppe pas son contenu

J'ai une application qui gère des collections de livres (comme des listes de lecture).

Je veux afficher une liste de collection avec un RecyclerView vertical et à l'intérieur de chaque ligne, une liste de livre dans un RecyclerView horizontal.

Lorsque je règle le layout_height du RecyclerView horizontal intérieur sur 300dp, il s'affiche correctement, mais lorsque je le règle sur wrap_content, il n'affiche rien. J'ai besoin d'utiliser wrap_content parce que je veux pouvoir changer le gestionnaire de disposition par programme pour basculer entre l'affichage vertical et horizontal.

Sais-tu ce que je fais de mal?

Ma mise en page Fragment:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/white">

    <com.twibit.ui.view.CustomSwipeToRefreshLayout
        android:id="@+id/swipe_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <android.support.v7.widget.RecyclerView
                android:id="@+id/shelf_collection_listview"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:paddingTop="10dp"/>

        </LinearLayout>

    </com.twibit.ui.view.CustomSwipeToRefreshLayout>
</LinearLayout>

Disposition des éléments de collection:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:orientation="vertical">

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#FFF">

        <!-- Simple Header -->

    </RelativeLayout>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@string/empty_collection"
            android:id="@+id/empty_collection_tv"
            android:visibility="gone"
            android:gravity="center"/>

        <android.support.v7.widget.RecyclerView
            android:id="@+id/collection_book_listview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/> <!-- android:layout_height="300dp" -->

    </FrameLayout>

</LinearLayout>

Élément de liste de livres:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="180dp"
              android:layout_height="220dp"
              android:layout_gravity="center">

        <ImageView
            android:id="@+id/shelf_item_cover"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:maxWidth="150dp"
            android:maxHeight="200dp"
            android:src="@drawable/placeholder"
            android:contentDescription="@string/cover"
            android:adjustViewBounds="true"
            android:background="@android:drawable/dialog_holo_light_frame"/>

</FrameLayout>

Voici mon adaptateur de collection:

private class CollectionsListAdapter extends RecyclerView.Adapter<CollectionsListAdapter.ViewHolder> {
    private final String TAG = CollectionsListAdapter.class.getSimpleName();
    private Context mContext;

    // Create the ViewHolder class to keep references to your views
    class ViewHolder extends RecyclerView.ViewHolder {

        private final TextView mHeaderTitleTextView;
        private final TextView mHeaderCountTextView;

        private final RecyclerView mHorizontalListView;
        private final TextView mEmptyTextView;

        public ViewHolder(View view) {
            super(view);

            mHeaderTitleTextView = (TextView) view.findViewById(R.id.collection_header_tv);
            mHeaderCountTextView = (TextView) view.findViewById(R.id.collection_header_count_tv);

            mHorizontalListView = (RecyclerView) view.findViewById(R.id.collection_book_listview);
            mEmptyTextView = (TextView) view.findViewById(R.id.empty_collection_tv);
        }
    }


    public CollectionsListAdapter(Context context) {
        mContext = context;
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int i) {
        Log.d(TAG, "CollectionsListAdapter.onCreateViewHolder(" + parent.getId() + ", " + i + ")");
        // Create a new view by inflating the row item xml.
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.shelf_collection, parent, false);

        // Set the view to the ViewHolder
        ViewHolder holder = new ViewHolder(v);

        holder.mHorizontalListView.setHasFixedSize(false);
        holder.mHorizontalListView.setHorizontalScrollBarEnabled(true);

        // use a linear layout manager
        LinearLayoutManager mLayoutManager = new LinearLayoutManager(mContext);
        mLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        holder.mHorizontalListView.setLayoutManager(mLayoutManager);

        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int i) {
        Log.d(TAG, "CollectionsListAdapter.onBindViewHolder(" + holder.getPosition() + ", " + i + ")");

        Collection collection = mCollectionList.get(i);
        Log.d(TAG, "Collection : " + collection.getLabel());

        holder.mHeaderTitleTextView.setText(collection.getLabel());
        holder.mHeaderCountTextView.setText("" + collection.getBooks().size());

        // Create an adapter if none exists
        if (!mBookListAdapterMap.containsKey(collection.getCollectionId())) {
            mBookListAdapterMap.put(collection.getCollectionId(), new BookListAdapter(getActivity(), collection));
        }

        holder.mHorizontalListView.setAdapter(mBookListAdapterMap.get(collection.getCollectionId()));

    }

    @Override
    public int getItemCount() {
        return mCollectionList.size();
    }
}

Et enfin, l'adaptateur Book:

private class BookListAdapter extends RecyclerView.Adapter<BookListAdapter.ViewHolder> implements View.OnClickListener {
    private final String TAG = BookListAdapter.class.getSimpleName();

    // Create the ViewHolder class to keep references to your views
    class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView mCoverImageView;

        public ViewHolder(View view) {
            super(view);
            mCoverImageView = (ImageView) view.findViewById(R.id.shelf_item_cover);
        }
    }

    @Override
    public void onClick(View v) {
        BookListAdapter.ViewHolder holder = (BookListAdapter.ViewHolder) v.getTag();
        int position = holder.getPosition();
        final Book book = mCollection.getBooks().get(position);

        // Click on cover image
        if (v.getId() == holder.mCoverImageView.getId()) {
            downloadOrOpenBook(book);
            return;
        }
    }

    private void downloadOrOpenBook(final Book book) {
        // do stuff
    }

    private Context mContext;
    private Collection mCollection;

    public BookListAdapter(Context context, Collection collection) {
        Log.d(TAG, "BookListAdapter(" + context + ", " + collection + ")");
        mCollection = collection;
        mContext = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int i) {
        Log.d(TAG, "onCreateViewHolder(" + parent.getId() + ", " + i + ")");
        // Create a new view by inflating the row item xml.
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.shelf_grid_item, parent, false);

        // Set the view to the ViewHolder
        ViewHolder holder = new ViewHolder(v);
        holder.mCoverImageView.setOnClickListener(BookListAdapter.this); // Download or Open

        holder.mCoverImageView.setTag(holder);

        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int i) {
        Log.d(TAG, "onBindViewHolder(" + holder.getPosition() + ", " + i + ")");

        Book book = mCollection.getBooks().get(i);

        ImageView imageView = holder.mCoverImageView;
        ImageLoader.getInstance().displayImage(book.getCoverUrl(), imageView);
    }

    @Override
    public int getItemCount() {
        return mCollection.getBooks().size();
    }
}

Mettre à jour

De nombreux problèmes liés à cette fonctionnalité dans la version 23.2.0 ont été corrigés dans 23.2.1, mettez à jour à la place.

Avec la sortie de la bibliothèque de support version 23.2, RecyclerViewprend désormais en charge cela!

Mettre build.gradleà jour vers:

compile 'com.android.support:recyclerview-v7:23.2.1'

ou toute autre version au-delà.

Cette version apporte une nouvelle fonctionnalité intéressante à l'API LayoutManager: la mesure automatique! Cela permet à un RecyclerView de se dimensionner en fonction de la taille de son contenu. Cela signifie que des scénarios précédemment indisponibles, tels que l'utilisation de WRAP_CONTENT pour une dimension de RecyclerView, sont désormais possibles. Vous constaterez que tous les LayoutManagers intégrés prennent désormais en charge la mesure automatique.

Cela peut être désactivé via setAutoMeasurementEnabled()si nécessaire. Vérifiez en détail ici .

La solution @ user2302510 ne fonctionne pas aussi bien que prévu. La solution de contournement complète pour les orientations et les modifications dynamiques des données est:

public class MyLinearLayoutManager extends LinearLayoutManager {

    public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
        super(context, orientation, reverseLayout);
    }

    private int[] mMeasuredDimension = new int[2];

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);
        int width = 0;
        int height = 0;
        for (int i = 0; i < getItemCount(); i++) {
            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    mMeasuredDimension);

            if (getOrientation() == HORIZONTAL) {
                width = width + mMeasuredDimension[0];
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                height = height + mMeasuredDimension[1];
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }
        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}

Le code ci-dessus ne fonctionne pas bien lorsque vous devez rendre vos éléments "wrap_content", car il mesure à la fois la hauteur et la largeur des éléments avec MeasureSpec.UNSPECIFIED. Après quelques problèmes, j'ai modifié cette solution afin que les éléments puissent maintenant se développer. La seule différence est qu'il fournit aux parents la hauteur ou la largeur. MeasureSpec dépend de l'orientation de la disposition.

public class MyLinearLayoutManager extends LinearLayoutManager {

public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
    super(context, orientation, reverseLayout);
}

private int[] mMeasuredDimension = new int[2];

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                      int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);
    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);
    int width = 0;
    int height = 0;
    for (int i = 0; i < getItemCount(); i++) {


        if (getOrientation() == HORIZONTAL) {

            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    heightSpec,
                    mMeasuredDimension);

            width = width + mMeasuredDimension[0];
            if (i == 0) {
                height = mMeasuredDimension[1];
            }
        } else {
            measureScrapChild(recycler, i,
                    widthSpec,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    mMeasuredDimension);
            height = height + mMeasuredDimension[1];
            if (i == 0) {
                width = mMeasuredDimension[0];
            }
        }
    }
    switch (widthMode) {
        case View.MeasureSpec.EXACTLY:
            width = widthSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
    }

    switch (heightMode) {
        case View.MeasureSpec.EXACTLY:
            height = heightSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
    }

    setMeasuredDimension(width, height);
}

private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                               int heightSpec, int[] measuredDimension) {
    View view = recycler.getViewForPosition(position);
    recycler.bindViewToPosition(view, position);
    if (view != null) {
        RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
        int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                getPaddingLeft() + getPaddingRight(), p.width);
        int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                getPaddingTop() + getPaddingBottom(), p.height);
        view.measure(childWidthSpec, childHeightSpec);
        measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
        measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
        recycler.recycleView(view);
    }
}
}

Le gestionnaire de mise en page existant ne prend pas encore en charge le contenu enveloppant.

Vous pouvez créer un nouveau LayoutManager qui étend l'existant et remplace la méthode onMeasure pour mesurer le contenu d'habillage.

Comme @ yiğit l'a mentionné, vous devez remplacer onMeasure (). @ User2302510 et @DenisNek ont ​​de bonnes réponses, mais si vous souhaitez prendre en charge ItemDecoration, vous pouvez utiliser ce gestionnaire de mise en page personnalisé.

Et les autres réponses ne peuvent pas défiler lorsqu'il y a plus d'éléments que ce qui peut être affiché à l'écran. Celui-ci utilise l'implémentation par défaut de onMeasure () lorsqu'il y a plus d'éléments que la taille de l'écran.

public class MyLinearLayoutManager extends LinearLayoutManager {

public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
    super(context, orientation, reverseLayout);
}

private int[] mMeasuredDimension = new int[2];

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                      int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);
    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);
    int width = 0;
    int height = 0;
    for (int i = 0; i < getItemCount(); i++) {
        measureScrapChild(recycler, i,
                View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                mMeasuredDimension);

        if (getOrientation() == HORIZONTAL) {
            width = width + mMeasuredDimension[0];
            if (i == 0) {
                height = mMeasuredDimension[1];
            }
        } else {
            height = height + mMeasuredDimension[1];
            if (i == 0) {
                width = mMeasuredDimension[0];
            }
        }
    }

    // If child view is more than screen size, there is no need to make it wrap content. We can use original onMeasure() so we can scroll view.
    if (height < heightSize && width < widthSize) {

        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    } else {
        super.onMeasure(recycler, state, widthSpec, heightSpec);
    }
}

private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                               int heightSpec, int[] measuredDimension) {

   View view = recycler.getViewForPosition(position);

   // For adding Item Decor Insets to view
   super.measureChildWithMargins(view, 0, 0);
    if (view != null) {
        RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
        int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight() + getDecoratedLeft(view) + getDecoratedRight(view), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom() + getPaddingBottom() + getDecoratedBottom(view) , p.height);
            view.measure(childWidthSpec, childHeightSpec);

            // Get decorated measurements
            measuredDimension[0] = getDecoratedMeasuredWidth(view) + p.leftMargin + p.rightMargin;
            measuredDimension[1] = getDecoratedMeasuredHeight(view) + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}

Et si vous voulez l'utiliser avec GridLayoutManager l'étend simplement de GridLayoutManager et changez

for (int i = 0; i < getItemCount(); i++)

à

for (int i = 0; i < getItemCount(); i = i + getSpanCount())

MISE À JOUR Mars 2016

Par Android Support Library 23.2.1 d'une version de bibliothèque de support. Donc, tout WRAP_CONTENT devrait fonctionner correctement.

Veuillez mettre à jour la version d'une bibliothèque dans le fichier gradle.

compile 'com.android.support:recyclerview-v7:23.2.1'

Cela permet à un RecyclerView de se dimensionner en fonction de la taille de son contenu. Cela signifie que des scénarios précédemment indisponibles, tels que l' utilisation de WRAP_CONTENT pour une dimension de RecyclerView, sont désormais possibles .

vous devrez appeler setAutoMeasureEnabled (true)

Correction de bugs liés à diverses méthodes de spécification de mesure dans la mise à jour

Vérifiez https://developer.android.com/topic/libraries/support-library/features.html

Cette réponse est basée sur la solution donnée par Denis Nek. Cela résout le problème de ne pas prendre en compte les décorations comme les diviseurs.

public class WrappingRecyclerViewLayoutManager extends LinearLayoutManager {

public WrappingRecyclerViewLayoutManager(Context context)    {
    super(context, VERTICAL, false);
}

public WrappingRecyclerViewLayoutManager(Context context, int orientation, boolean reverseLayout)    {
    super(context, orientation, reverseLayout);
}

private int[] mMeasuredDimension = new int[2];

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);
    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);
    int width = 0;
    int height = 0;
    for (int i = 0; i < getItemCount(); i++) {
        measureScrapChild(recycler, i,
                View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                mMeasuredDimension);
        if (getOrientation() == HORIZONTAL) {
            width = width + mMeasuredDimension[0];
            if (i == 0) {
                height = mMeasuredDimension[1];
            }
        } else {
            height = height + mMeasuredDimension[1];
            if (i == 0) {
                width = mMeasuredDimension[0];
            }
        }
    }
    switch (widthMode) {
        case View.MeasureSpec.EXACTLY:
            width = widthSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
    }

    switch (heightMode) {
        case View.MeasureSpec.EXACTLY:
            height = heightSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
    }

    setMeasuredDimension(width, height);
}

private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec, int heightSpec, int[] measuredDimension) {
    View view = recycler.getViewForPosition(position);
    if (view != null) {
        RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
        int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec, getPaddingLeft() + getPaddingRight(), p.width);
        int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec, getPaddingTop() + getPaddingBottom(), p.height);
        view.measure(childWidthSpec, childHeightSpec);
        Rect outRect = new Rect();
        calculateItemDecorationsForChild(view, outRect);
        measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
        measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin + outRect.bottom + outRect.top;
        recycler.recycleView(view);
    }
}

}

Une alternative pour étendre LayoutManager peut simplement être de définir manuellement la taille de la vue.

Nombre d'éléments par hauteur de ligne (si tous les éléments ont la même hauteur et que le séparateur est inclus sur la ligne)

LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) mListView.getLayoutParams();
params.height = mAdapter.getItemCount() * getResources().getDimensionPixelSize(R.dimen.row_height);
mListView.setLayoutParams(params);

Est toujours une solution de contournement, mais pour les cas de base, cela fonctionne.

Ici, j'ai trouvé une solution: https://code.google.com/p/android/issues/detail?id=74772

Ce n'est en aucun cas ma solution. Je viens de le copier à partir de là, mais j'espère que cela aidera quelqu'un autant que cela m'a aidé lors de la mise en œuvre de RecyclerView horizontal et de la hauteur wrap_content (devrait fonctionner aussi pour un vertical et wrap_content width)

La solution consiste à étendre le LayoutManager et à remplacer sa méthode onMeasure comme @yigit le suggère.

Voici le code au cas où le lien meurt:

public static class MyLinearLayoutManager extends LinearLayoutManager {

    public MyLinearLayoutManager(Context context) {
        super(context);
    }

    private int[] mMeasuredDimension = new int[2];

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);

        measureScrapChild(recycler, 0,
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                mMeasuredDimension);

        int width = mMeasuredDimension[0];
        int height = mMeasuredDimension[1];

        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
            case View.MeasureSpec.AT_MOST:
                width = widthSize;
                break;
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
            case View.MeasureSpec.AT_MOST:
                height = heightSize;
                break;
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth();
            measuredDimension[1] = view.getMeasuredHeight();
            recycler.recycleView(view);
        }
    }
}

Solution utilisée de @ sinan-kozak, sauf correction de quelques bugs. Plus précisément, nous ne devons pas utiliser View.MeasureSpec.UNSPECIFIEDà la fois la largeur et la hauteur lors de l'appel, measureScrapChildcar cela ne tiendra pas correctement compte du texte enveloppé dans l'enfant. Au lieu de cela, nous passerons par les modes largeur et hauteur du parent, ce qui permettra aux choses de fonctionner à la fois pour les dispositions horizontales et verticales.

public class MyLinearLayoutManager extends LinearLayoutManager {

public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
    super(context, orientation, reverseLayout);
}

private int[] mMeasuredDimension = new int[2];

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                      int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);
    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);
    int width = 0;
    int height = 0;
    for (int i = 0; i < getItemCount(); i++) {    
        if (getOrientation() == HORIZONTAL) {
            measureScrapChild(recycler, i,
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                View.MeasureSpec.makeMeasureSpec(heightSize, heightMode),
                mMeasuredDimension);

            width = width + mMeasuredDimension[0];
            if (i == 0) {
                height = mMeasuredDimension[1];
            }
        } else {
            measureScrapChild(recycler, i,
                View.MeasureSpec.makeMeasureSpec(widthSize, widthMode),
                View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
                mMeasuredDimension);

            height = height + mMeasuredDimension[1];
            if (i == 0) {
                width = mMeasuredDimension[0];
            }
        }
    }

    // If child view is more than screen size, there is no need to make it wrap content. We can use original onMeasure() so we can scroll view.
    if (height < heightSize && width < widthSize) {

        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    } else {
        super.onMeasure(recycler, state, widthSpec, heightSpec);
    }
}

private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                               int heightSpec, int[] measuredDimension) {

   View view = recycler.getViewForPosition(position);

   // For adding Item Decor Insets to view
   super.measureChildWithMargins(view, 0, 0);
    if (view != null) {
        RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
        int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight() + getDecoratedLeft(view) + getDecoratedRight(view), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom() + getDecoratedTop(view) + getDecoratedBottom(view) , p.height);
            view.measure(childWidthSpec, childHeightSpec);

            // Get decorated measurements
            measuredDimension[0] = getDecoratedMeasuredWidth(view) + p.leftMargin + p.rightMargin;
            measuredDimension[1] = getDecoratedMeasuredHeight(view) + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}

»

Oui, la solution de contournement indiquée dans toutes les réponses est correcte, c'est-à-dire que nous devons personnaliser le gestionnaire de disposition linéaire pour calculer la hauteur de ses éléments enfants de manière dynamique au moment de l'exécution. Mais toutes les réponses ne fonctionnent pas comme prévu. Veuillez la réponse ci-dessous pour le gestionnaire de mise en page personnalisé avec tout le support d'orientation.

public class MyLinearLayoutManager extends android.support.v7.widget.LinearLayoutManager {

private static boolean canMakeInsetsDirty = true;
private static Field insetsDirtyField = null;

private static final int CHILD_WIDTH = 0;
private static final int CHILD_HEIGHT = 1;
private static final int DEFAULT_CHILD_SIZE = 100;

private final int[] childDimensions = new int[2];
private final RecyclerView view;

private int childSize = DEFAULT_CHILD_SIZE;
private boolean hasChildSize;
private int overScrollMode = ViewCompat.OVER_SCROLL_ALWAYS;
private final Rect tmpRect = new Rect();

@SuppressWarnings("UnusedDeclaration")
public MyLinearLayoutManager(Context context) {
    super(context);
    this.view = null;
}

@SuppressWarnings("UnusedDeclaration")
public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
    super(context, orientation, reverseLayout);
    this.view = null;
}

@SuppressWarnings("UnusedDeclaration")
public MyLinearLayoutManager(RecyclerView view) {
    super(view.getContext());
    this.view = view;
    this.overScrollMode = ViewCompat.getOverScrollMode(view);
}

@SuppressWarnings("UnusedDeclaration")
public MyLinearLayoutManager(RecyclerView view, int orientation, boolean reverseLayout) {
    super(view.getContext(), orientation, reverseLayout);
    this.view = view;
    this.overScrollMode = ViewCompat.getOverScrollMode(view);
}

public void setOverScrollMode(int overScrollMode) {
    if (overScrollMode < ViewCompat.OVER_SCROLL_ALWAYS || overScrollMode > ViewCompat.OVER_SCROLL_NEVER)
        throw new IllegalArgumentException("Unknown overscroll mode: " + overScrollMode);
    if (this.view == null) throw new IllegalStateException("view == null");
    this.overScrollMode = overScrollMode;
    ViewCompat.setOverScrollMode(view, overScrollMode);
}

public static int makeUnspecifiedSpec() {
    return View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
}

@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
    final int widthMode = View.MeasureSpec.getMode(widthSpec);
    final int heightMode = View.MeasureSpec.getMode(heightSpec);

    final int widthSize = View.MeasureSpec.getSize(widthSpec);
    final int heightSize = View.MeasureSpec.getSize(heightSpec);

    final boolean hasWidthSize = widthMode != View.MeasureSpec.UNSPECIFIED;
    final boolean hasHeightSize = heightMode != View.MeasureSpec.UNSPECIFIED;

    final boolean exactWidth = widthMode == View.MeasureSpec.EXACTLY;
    final boolean exactHeight = heightMode == View.MeasureSpec.EXACTLY;

    final int unspecified = makeUnspecifiedSpec();

    if (exactWidth && exactHeight) {
        // in case of exact calculations for both dimensions let's use default "onMeasure" implementation
        super.onMeasure(recycler, state, widthSpec, heightSpec);
        return;
    }

    final boolean vertical = getOrientation() == VERTICAL;

    initChildDimensions(widthSize, heightSize, vertical);

    int width = 0;
    int height = 0;

    // it's possible to get scrap views in recycler which are bound to old (invalid) adapter entities. This
    // happens because their invalidation happens after "onMeasure" method. As a workaround let's clear the
    // recycler now (it should not cause any performance issues while scrolling as "onMeasure" is never
    // called whiles scrolling)
    recycler.clear();

    final int stateItemCount = state.getItemCount();
    final int adapterItemCount = getItemCount();
    // adapter always contains actual data while state might contain old data (f.e. data before the animation is
    // done). As we want to measure the view with actual data we must use data from the adapter and not from  the
    // state
    for (int i = 0; i < adapterItemCount; i++) {
        if (vertical) {
            if (!hasChildSize) {
                if (i < stateItemCount) {
                    // we should not exceed state count, otherwise we'll get IndexOutOfBoundsException. For such items
                    // we will use previously calculated dimensions
                    measureChild(recycler, i, widthSize, unspecified, childDimensions);
                } else {
                    logMeasureWarning(i);
                }
            }
            height += childDimensions[CHILD_HEIGHT];
            if (i == 0) {
                width = childDimensions[CHILD_WIDTH];
            }
            if (hasHeightSize && height >= heightSize) {
                break;
            }
        } else {
            if (!hasChildSize) {
                if (i < stateItemCount) {
                    // we should not exceed state count, otherwise we'll get IndexOutOfBoundsException. For such items
                    // we will use previously calculated dimensions
                    measureChild(recycler, i, unspecified, heightSize, childDimensions);
                } else {
                    logMeasureWarning(i);
                }
            }
            width += childDimensions[CHILD_WIDTH];
            if (i == 0) {
                height = childDimensions[CHILD_HEIGHT];
            }
            if (hasWidthSize && width >= widthSize) {
                break;
            }
        }
    }

    if (exactWidth) {
        width = widthSize;
    } else {
        width += getPaddingLeft() + getPaddingRight();
        if (hasWidthSize) {
            width = Math.min(width, widthSize);
        }
    }

    if (exactHeight) {
        height = heightSize;
    } else {
        height += getPaddingTop() + getPaddingBottom();
        if (hasHeightSize) {
            height = Math.min(height, heightSize);
        }
    }

    setMeasuredDimension(width, height);

    if (view != null && overScrollMode == ViewCompat.OVER_SCROLL_IF_CONTENT_SCROLLS) {
        final boolean fit = (vertical && (!hasHeightSize || height < heightSize))
                || (!vertical && (!hasWidthSize || width < widthSize));

        ViewCompat.setOverScrollMode(view, fit ? ViewCompat.OVER_SCROLL_NEVER : ViewCompat.OVER_SCROLL_ALWAYS);
    }
}

private void logMeasureWarning(int child) {
    if (BuildConfig.DEBUG) {
        Log.w("MyLinearLayoutManager", "Can't measure child #" + child + ", previously used dimensions will be reused." +
                "To remove this message either use #setChildSize() method or don't run RecyclerView animations");
    }
}

private void initChildDimensions(int width, int height, boolean vertical) {
    if (childDimensions[CHILD_WIDTH] != 0 || childDimensions[CHILD_HEIGHT] != 0) {
        // already initialized, skipping
        return;
    }
    if (vertical) {
        childDimensions[CHILD_WIDTH] = width;
        childDimensions[CHILD_HEIGHT] = childSize;
    } else {
        childDimensions[CHILD_WIDTH] = childSize;
        childDimensions[CHILD_HEIGHT] = height;
    }
}

@Override
public void setOrientation(int orientation) {
    // might be called before the constructor of this class is called
    //noinspection ConstantConditions
    if (childDimensions != null) {
        if (getOrientation() != orientation) {
            childDimensions[CHILD_WIDTH] = 0;
            childDimensions[CHILD_HEIGHT] = 0;
        }
    }
    super.setOrientation(orientation);
}

public void clearChildSize() {
    hasChildSize = false;
    setChildSize(DEFAULT_CHILD_SIZE);
}

public void setChildSize(int childSize) {
    hasChildSize = true;
    if (this.childSize != childSize) {
        this.childSize = childSize;
        requestLayout();
    }
}

private void measureChild(RecyclerView.Recycler recycler, int position, int widthSize, int heightSize, int[] dimensions) {
    final View child;
    try {
        child = recycler.getViewForPosition(position);
    } catch (IndexOutOfBoundsException e) {
        if (BuildConfig.DEBUG) {
            Log.w("MyLinearLayoutManager", "MyLinearLayoutManager doesn't work well with animations. Consider switching them off", e);
        }
        return;
    }

    final RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) child.getLayoutParams();

    final int hPadding = getPaddingLeft() + getPaddingRight();
    final int vPadding = getPaddingTop() + getPaddingBottom();

    final int hMargin = p.leftMargin + p.rightMargin;
    final int vMargin = p.topMargin + p.bottomMargin;

    // we must make insets dirty in order calculateItemDecorationsForChild to work
    makeInsetsDirty(p);
    // this method should be called before any getXxxDecorationXxx() methods
    calculateItemDecorationsForChild(child, tmpRect);

    final int hDecoration = getRightDecorationWidth(child) + getLeftDecorationWidth(child);
    final int vDecoration = getTopDecorationHeight(child) + getBottomDecorationHeight(child);

    final int childWidthSpec = getChildMeasureSpec(widthSize, hPadding + hMargin + hDecoration, p.width, canScrollHorizontally());
    final int childHeightSpec = getChildMeasureSpec(heightSize, vPadding + vMargin + vDecoration, p.height, canScrollVertically());

    child.measure(childWidthSpec, childHeightSpec);

    dimensions[CHILD_WIDTH] = getDecoratedMeasuredWidth(child) + p.leftMargin + p.rightMargin;
    dimensions[CHILD_HEIGHT] = getDecoratedMeasuredHeight(child) + p.bottomMargin + p.topMargin;

    // as view is recycled let's not keep old measured values
    makeInsetsDirty(p);
    recycler.recycleView(child);
}

private static void makeInsetsDirty(RecyclerView.LayoutParams p) {
    if (!canMakeInsetsDirty) {
        return;
    }
    try {
        if (insetsDirtyField == null) {
            insetsDirtyField = RecyclerView.LayoutParams.class.getDeclaredField("mInsetsDirty");
            insetsDirtyField.setAccessible(true);
        }
        insetsDirtyField.set(p, true);
    } catch (NoSuchFieldException e) {
        onMakeInsertDirtyFailed();
    } catch (IllegalAccessException e) {
        onMakeInsertDirtyFailed();
    }
}

private static void onMakeInsertDirtyFailed() {
    canMakeInsetsDirty = false;
    if (BuildConfig.DEBUG) {
        Log.w("MyLinearLayoutManager", "Can't make LayoutParams insets dirty, decorations measurements might be incorrect");
    }
}
}

La bibliothèque de support Android gère désormais également la propriété WRAP_CONTENT. Importez simplement ceci dans votre gradle.

compile 'com.android.support:recyclerview-v7:23.2.0'

Et.. Voila!

Basé sur le travail de Denis Nek, cela fonctionne bien si la somme des largeurs de l'article est inférieure à la taille du conteneur. à part cela, cela rendra la vue de recyclage non défilable et affichera uniquement un sous-ensemble des données.

pour résoudre ce problème, j'ai modifié un peu la solution pour qu'elle choisisse le min de la taille fournie et la taille calculée. voir ci-dessous:

package com.linkdev.gafi.adapters;

import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;

import com.linkdev.gafi.R;

public class MyLinearLayoutManager extends LinearLayoutManager {

    public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
        super(context, orientation, reverseLayout);
        this.c = context;
    }


    private Context c;
    private int[] mMeasuredDimension = new int[2];


    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);



        int width = 0;
        int height = 0;
        for (int i = 0; i < getItemCount(); i++) {
            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    mMeasuredDimension);

            if (getOrientation() == HORIZONTAL) {
                width = width + mMeasuredDimension[0];
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                height = height + mMeasuredDimension[1];
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }


        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        int widthDesired = Math.min(widthSize,width);
        setMeasuredDimension(widthDesired, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }}

J'ai essayé toutes les solutions, elles sont très utiles mais cela ne fonctionne que pour moi

public class  LinearLayoutManager extends android.support.v7.widget.LinearLayoutManager {

    public LinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
        super(context, orientation, reverseLayout);
    }

    private int[] mMeasuredDimension = new int[2];

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);
        int width = 0;
        int height = 0;
        for (int i = 0; i < getItemCount(); i++) {


            if (getOrientation() == HORIZONTAL) {

                measureScrapChild(recycler, i,
                        View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                        heightSpec,
                        mMeasuredDimension);

                width = width + mMeasuredDimension[0];
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                measureScrapChild(recycler, i,
                        widthSpec,
                        View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                        mMeasuredDimension);
                height = height + mMeasuredDimension[1];
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }

        if (height < heightSize || width < widthSize) {

            switch (widthMode) {
                case View.MeasureSpec.EXACTLY:
                    width = widthSize;
                case View.MeasureSpec.AT_MOST:
                case View.MeasureSpec.UNSPECIFIED:
            }

            switch (heightMode) {
                case View.MeasureSpec.EXACTLY:
                    height = heightSize;
                case View.MeasureSpec.AT_MOST:
                case View.MeasureSpec.UNSPECIFIED:
            }

            setMeasuredDimension(width, height);
        } else {
            super.onMeasure(recycler, state, widthSpec, heightSpec);
        }
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        recycler.bindViewToPosition(view, position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}