嵌套的Recycler视图高度不包裹其内容

我有一个pipe理书籍（如播放列表）的应用程序。

我想要显示一个垂直RecyclerView的集合列表，并在每行内部显示一个水平RecyclerView的书籍列表。

当我将内部水平RecyclerView的layout_height设置为300dp时，它显示正确，但是当我将其设置为wrap_content时，它不显示任何内容。 我需要使用wrap_content，因为我希望能够以编程方式更改布局pipe理器以在垂直和水平显示之间切换。

你知道我在做什么错吗？

我的片段布局：

<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> 

集合元素布局：

 <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> 

图书清单项目：

 <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> 

这是我的收集适配器：

 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(); } } 

最后，Book适配器：

 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(); } } 

Answer 1

更新

在23.2.1中，与23.2.0版中的这个特性有关的许多问题已经被修正，而是更新到23.2.1。

随着支持库版本23.2的发布， RecyclerView现在支持！

更新build.gradle到：

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

或者其他任何版本。

此版本为LayoutManager API带来了令人兴奋的新function：自动测量！ 这允许RecyclerView根据其内容的大小自行resize。 这意味着以前不可用的scheme，例如对RecyclerView的维度使用WRAP_CONTENT，现在是可能的。 您会发现所有内置的LayoutManagers现在都支持自动测量。

如果需要，可以通过setAutoMeasurementEnabled()来禁用。 在这里详细检查。

Answer 2

@ user2302510解决scheme的工作不如您预期的那样好。 对方向和dynamic数据更改的全面解决方法是：

 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); } } } 

Answer 3

上面的代码在您需要使项目“wrap_content”时不能正常工作，因为它使用MeasureSpec.UNSPECIFIED测量两个项目的高度和宽度。 经过一些麻烦，我修改了这个解决scheme，现在可以扩展项目。 唯一的区别是它提供父母的高度或宽度MeasureSpec取决于布局方向。

 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); } } } 

Answer 4

现有的布局pipe理器还不支持换行内容。

您可以创build一个新的扩展现有的LayoutManager，并覆盖onMeasure方法来测量换行内容。

Answer 5

作为@yiğit提到，你需要重写onMeasure（）。 @ user2302510和@DenisNek都有很好的答案，但是如果你想支持ItemDecoration，你可以使用这个自定义布局pipe理器。

而其他答案不能滚动，当有更多的项目可以显示在屏幕上，虽然。 当有更多的项目比屏幕大小时，这是使用onMeasure（）的默认实现。

 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); } } } 

如果你想使用GridLayoutManager，只要从GridLayoutManager扩展它就可以了

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

至

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

Answer 6

更新2016年3月

通过Android支持库23.2.1的支持库版本。 所以所有的WRAP_CONTENT都应该正常工作。

请在gradle文件中更新库的版本。

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

这允许RecyclerView根据其内容的大小自行resize。 这意味着以前不可用的scheme，例如对RecyclerView的维度使用WRAP_CONTENT，现在是可能的 。

你将被要求调用setAutoMeasureEnabled（true）

修正了与更新中的各种度量规格方法相关的错误

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

Answer 7

这个答案是基于Denis Nek给出的解决scheme。 它解决了不考虑分隔线等装饰的问题。

 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); } } 

}

Answer 8

扩展LayoutManager的替代方法可以只是手动设置视图的大小。

每行高度的项目数（如果所有项目具有相同的高度，并且分隔符包含在行中）

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

仍然是一个解决方法，但基本情况下，它的工作原理。

Answer 9

从@ sinan-kozak使用的解决scheme，除了修复了一些错误。 具体而言，在调用measureScrapChild时，我们不应该使用View.MeasureSpec.UNSPECIFIED来指定宽度和高度，因为这将无法正确计算子项中的包装文本。 相反，我们将通过父级的宽度和高度模式，这将允许事物适用于水平和垂直布局。

 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); } } } 

`

Answer 10

在这里，我find了一个解决scheme： https ： //code.google.com/p/android/issues/detail？id = 74772

这绝不是我的解决scheme。 我刚刚从那里复制它，但我希望它会帮助一个人，因为它实现水平RecyclerView和wrap_content高度时（它也应该为垂直和wrap_content宽度）

解决的办法是扩展LayoutManager，并像@yigitbuild议的那样覆盖它的onMeasure方法。

以下是链接死亡时的代码：

 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); } } } 

Answer 11

Android支持库现在还可以处理WRAP_CONTENT属性。 只要在你的gradle中导入这个。

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

并做了！

Answer 12

根据Denis Nek的工作，如果项目宽度的总和小于容器的大小，则工作得很好。 除此之外，这将使recyclerview不可滚动，只会显示数据的子集。

为了解决这个问题，我修改了解决scheme，以便它select提供的大小和计算大小的最小值。 见下文：

 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); } }} 

Answer 13

I have tried all solutions, they are very useful but this only works fine for me

 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); } } } 

Answer 14

Yes the workaround shown in all answer is correct , that is we need to customize the linear layout manager to calculate the height of its child items dynamically at run time. But all answers not working as expected .Please the below answer for custom layout manger with all orientation support.

 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 (fe 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"); } } }