Android中RecyclerView与Scrollview组合使用（二）

1、LinearLayoutManager和ScrollView嵌套

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);
            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 {
        }
    }
}

2、GridLayoutManager和ScrollView进行嵌套

public class FullyGridLayoutManager  extends GridLayoutManager {
    public FullyGridLayoutManager(Context context, int spanCount) {
        super(context, spanCount);
    }
    public FullyGridLayoutManager(Context context, int spanCount, int orientation, boolean reverseLayout) {
        super(context, spanCount, 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;
        int count = getItemCount();
        int span = getSpanCount();
        for (int i = 0; i < count; i++) {
            measureScrapChild(recycler, i, View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED), mMeasuredDimension);

            if (getOrientation() == HORIZONTAL) {
                if (i % span == 0) {
                    width = width + mMeasuredDimension[0];
                }
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
                if (i % span == 0) {
                    height = height + mMeasuredDimension[1];
                }
            }
        }
        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) {
        if (position < getItemCount()) {
            try {
                View view = recycler.getViewForPosition(0);
                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();
            }
        }
    }
}

3、StaggeredGridLayoutManager和ScrollView进行嵌套

public class FullyStaggeredGridLayoutManager extends StaggeredGridLayoutManager {
    public FullyStaggeredGridLayoutManager(int spanCount, int orientation) {
        super(spanCount, orientation);
    }
    // 尺寸的数组，[0]是宽，[1]是高
    private int[] measuredDimension = new int[2];
    // 用来比较同行/列那个item罪宽/高
    private int[] dimension;
    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
        // 宽的mode+size
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        // 高的mode + size
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);
        // 自身宽高的初始值
        int width = 0;
        int height = 0;
        // item的数目
        int count = getItemCount();
        // item的列数
        int span = getSpanCount();
        // 根据行数或列数来创建数组
        dimension = new int[span];

        for (int i = 0; i < count; i++) {
            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED), measuredDimension);
            // 如果是竖直的列表，计算item的高，否则计算宽度
            //Log.d("LISTENER", "position " + i + " height = " + measuredDimension[1]);
            if (getOrientation() == VERTICAL) {
                dimension[findMinIndex(dimension)] += measuredDimension[1];
            } else {
                dimension[findMinIndex(dimension)] += measuredDimension[0];
            }
        }
        if (getOrientation() == VERTICAL) {
            height = findMax(dimension);
        } else {
            width = findMax(dimension);
        }
        switch (widthMode) {
            // 当控件宽是match_parent时，宽度就是父控件的宽度
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
                break;
            case View.MeasureSpec.AT_MOST:
                break;
            case View.MeasureSpec.UNSPECIFIED:
                break;
        }
        switch (heightMode) {
            // 当控件高是match_parent时，高度就是父控件的高度
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
                break;
            case View.MeasureSpec.AT_MOST:
                break;
            case View.MeasureSpec.UNSPECIFIED:
                break;
        }
        // 设置测量尺寸  
        setMeasuredDimension(width, height);
    }

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

        // 挨个遍历所有item
        if (position < getItemCount()) {
            try {
                View view = recycler.getViewForPosition(position);//fix 动态添加时报IndexOutOfBoundsException
                if (view != null) {
                    RecyclerView.LayoutParams lp = (RecyclerView.LayoutParams) view.getLayoutParams();
                    int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec, getPaddingLeft() + getPaddingRight(), lp.width);
                    int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec, getPaddingTop() + getPaddingBottom(), lp.height);
                    // 子view进行测量，然后可以通过getMeasuredWidth()获得测量的宽，高类似
                    view.measure(childWidthSpec, childHeightSpec);
                    // 将item的宽高放入数组中
                    measuredDimension[0] = view.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
                    measuredDimension[1] = view.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
                    recycler.recycleView(view);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    private int findMax(int[] array) {
        int max = array[0];
        for (int value : array) {
            if (value > max) {
                max = value;
            }
        }
        return max;
    }

    /**
     * 得到最数组中最小元素的下标
     *
     * @param array
     * @return
     */
    private int findMinIndex(int[] array) {
        int index = 0;
        int min = array[0];
        for (int i = 0; i < array.length; i++) {
            if (array[i] < min) {
                min = array[i];
                index = i;
            }
        }
        return index;
    }
}

4、重写ScrollView

public class MyScrollview extends ScrollView {
    private int downY;
    private int mTouchSlop;

    public MyScrollview(Context context) {
        super(context);
        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

    public MyScrollview(Context context, AttributeSet attrs) {
        super(context, attrs);
        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

    public MyScrollview(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        int action = event.getAction();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                downY = (int) event.getRawY();
                break;
            case MotionEvent.ACTION_MOVE:
                int moveY = (int) event.getRawY();
                if (Math.abs(moveY - downY) > mTouchSlop) {
                    return true;
                }
        }
        return super.onInterceptTouchEvent(event);
    }
}

5、注意事项
（1）RecyclerView外层要嵌套RelativeLayout
Android中RecyclerView的下拉刷新和上拉加载使用（三）