android - 设置内部 RecyclerView wrap_content 的高度

Question

我在另一个 recyclerview 中有一个 recyclerview。我想使内部 recyclerview 的高度为“warp_content”。

我开始知道可以使用下面提到的新版本的 recyclerview。

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

但问题是，通过设置 height = wrap_content 我只能看到第一个项目。

任何帮助都会很棒。

Answer 1

因为我使用的是 RecyclerView 这不起作用，请参阅:

https://code.google.com/p/android/issues/detail?id=74772

和

嵌套的 Recycler View 高度不包裹它的内容

在这两个页面上，人们建议扩展 LinearLayoutManager 并覆盖 onMeasure()

RecyclerView 默认没有 wrap_content。您必须将 RecyclerView 与 wrap_content 布局管理器一起使用，例如 WrapLinearLayoutManager 例如 CustomLinearLayoutManager 。

CustomLinearLayoutManager.java

    public class CustomLinearLayoutManager extends LinearLayoutManager {

private static final String TAG = CustomLinearLayoutManager.class.getSimpleName();

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

public CustomLinearLayoutManager(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) {
    try {
        View view = recycler.getViewForPosition(0);//fix 动态添加时报IndexOutOfBoundsException

        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);
        }
    } catch (Exception e) {
        e.printStackTrace();
    } 
}