android HorizontalScrollView嵌套RecyclerView横向不能滑动问题

本文主要是介绍android HorizontalScrollView嵌套RecyclerView横向不能滑动问题，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

开发场景：在 HorizontalScrollView内嵌套RecyclerView和其他内容，要求其他控件和RecyclerView一起横向滑动，而RecyclerView自身滑动事件不响应。

问题分析：1.HorizontalScrollView内嵌套RecyclerView，发现HorizontalScrollView不能横向滑动；

2.RecyclerView于HorizontalScrollView的滑动冲突。

这个需求所面临的问题里面，第二个问题的解决方案很多，例如重写HorizontalScrollView，阻止滑动事件的传递。

首先来看第一个问题的解决方案：

第一，当我把HorizontalScrollView内嵌RecyclerView工程跑起来后，发现不能够滑动，重写RecyclerView的LinearLayoutManager，主要重写onMeasure方法，来计算出width和height。示例代码如下：

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:}width += 30 * getItemCount();

        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);
        }}
}

解释下为什么会有下面这一句，因为设置了RecyclerView的间距，重写了RecyclerView.ItemDecoration方法，每一个item的间距设置了30px，所以，为了让ui显示完整，得加上下面这句代码，如果不需要设置间距，删除下面代码。

感慨下，代码还是比较简陋的，毕竟是demo

width += 30 * getItemCount();

另外，使用控件的时候，还需要给控件设置下面的属性

recyclerView.setNestedScrollingEnabled(false)

第二，重写RecyclerView，来阻止事件的分发，从而达到recyclerView不能滑动的问题，示例代码如下：

public class MyScollView extends HorizontalScrollView {public MyScollView(Context context) {super(context);
    }public MyScollView(Context context, @Nullable AttributeSet attrs) {super(context, attrs);
    }public MyScollView(Context context, @Nullable AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);
    }private float lastX, lastY;

    @Override
    public boolean onInterceptTouchEvent(MotionEvent e) {boolean intercept = super.onInterceptTouchEvent(e);

        switch (e.getAction()) {case MotionEvent.ACTION_DOWN:lastX = e.getX();
                lastY = e.getY();
                break;
            case MotionEvent.ACTION_MOVE:// 只要横向大于竖向，就拦截掉事件。
                // 部分机型点击事件（slopx==slopy==0），会触发MOVE事件。
                // 所以要加判断(slopX > 0 || sloy > 0)
                float slopX = Math.abs(e.getX() - lastX);
                float slopY = Math.abs(e.getY() - lastY);
                //  Log.log("slopX=" + slopX + ", slopY="  + slopY);
                if((slopX > 0 || slopY > 0) && slopX >= slopY){requestDisallowInterceptTouchEvent(true);
                    intercept = true;
                }break;
            case MotionEvent.ACTION_UP:intercept = false;
                break;
        }// Log.log("intercept"+e.getAction()+"=" + intercept);
        return intercept;
    }
}