RecyclerView自适应高度

近期代码中需要用到recyclerview自适应高度的功能，其自适应高度并不能像gridview或者listview那样自定义view，而是应该用自定义layoutmanager来进行控制

**
 * Created by $ Ping.sir on 2018/5/3.
 * recyclerView自适应高度
 */

public class MyGridLayoutManager extends GridLayoutManager {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 int childSize = DEFAULT_CHILD_SIZE;
    private boolean hasChildSize;

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

    public MyGridLayoutManager(Context context, int spanCount, int orientation, boolean reverseLayout) {super(context, spanCount, orientation, reverseLayout);
    }@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++) {try {measureScrapChild(recycler, i,
                        widthSpec,
                        View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                        mMeasuredDimension);
            } catch (IndexOutOfBoundsException e) {e.printStackTrace();
            }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(widthSpec, 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 childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(widthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }}@Override
    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
//        Logger.e("SyLinearLayoutManager state:" + state.toString());
        super.onLayoutChildren(recycler, state);
    }
}