前言

做 Android開發我們經常會遇到這種ScrollView巢狀Listview或者 巢狀RecyclerView的需求，當我們搜尋解決方案時經常會遇到這句話

you should never put a scrollable view inside another scrollable view

雖然很多人不推薦這種方法，但是總有一些人（比如我）面對產品設計的一些奇葩介面不得不採用這種方案，今天我就把我找到的Scrollview巢狀Recyclerview高度顯示不全解決辦法總結一下。（ScrollView巢狀Listview的情況也是老生常談的話題，網上太多就不再贅述）

首先

網上已經有前人給我們寫出了一個自定義的LinearLayoutManager，我相信你也可以搜尋到，下面我先粘貼出來，感興趣建議好好看看這個類的原始碼，不要只做搬運工，知其然也要知其所以然，但是使用中會遇到一些小問題，下面講解

/**
 * 工具類 用於Scrollview巢狀recyclerview
 * 2017 2 17加入
 */
public class FullyLinearLayoutManager extends LinearLayoutManager {

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

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

    public FullyLinearLayoutManager(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);

        Log.i(TAG, "onMeasure called. \nwidthMode " + widthMode
                + " \nheightMode " + heightSpec
                + " \nwidthSize " + widthSize
                + " \nheightSize " + heightSize
                + " \ngetItemCount() " + getItemCount());

        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 動態新增時報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();
        } finally {
        }
    }
}

小問題，值得注意的地方

1，

給scrollview加入一個屬性

android:fillViewport="true"

2,

處理滑動衝突情況，如下設定

recyclerView.setNestedScrollingEnabled(false);

3,

我開始用的scrollview，測試裝置：小米note黑 adnroid6.0,由於我的裡面有兩個RecyclerView我發現下面的超出螢幕的部分就不顯示了，其他的機型是可以的。網上搜索建議將Scrollview換成android.support.v4.widget.NestedScrollView，我試了一下確實正常工作了

總結

you should never put a scrollable view inside another scrollable view

如果這個介面確實要求不高，這樣寫確實省了不少功夫，那就這樣幹吧！