解决ScrollView中嵌套EditText无法滑动的问题

因为项目需求，需要在ScrollView中放EditText, 但是发现如果EditText里面内容过多时无法上下滑动，上网搜索了下，发现解决方式基本如下:

    private void initializeEditText()
    {
        editText.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                editText.getParent().requestDisallowInterceptTouchEvent(true);

                switch (motionEvent.getAction() & MotionEvent.ACTION_MASK)
                {
                    case MotionEvent.ACTION_UP:
                        editText.getParent().requestDisallowInterceptTouchEvent(false);
                        break;
                }

                return false;
            }
        });
    }

但是我发现虽然EditText可以滑动了，但是当EditText中的内同比较少或者滑动到顶部或底部后，ScrollView不会滑动，感觉效果不好，所以想解决这个问题。
正好在View.class中发现了一个方法可以判断View是否可以向上（传正值）或向下（传负值）滑动:

    /**
     * Check if this view can be scrolled vertically in a certain direction.
     *
     * @param direction Negative to check scrolling up, positive to check scrolling down.
     * @return true if this view can be scrolled in the specified direction, false otherwise.
     */
    public boolean canScrollVertically(int direction) {
        final int offset = computeVerticalScrollOffset();
        final int range = computeVerticalScrollRange() - computeVerticalScrollExtent();
        if (range == 0) return false;
        if (direction < 0) {
            return offset > 0;
        } else {
            return offset < range - 1;
        }
    }

最终我的代码时这样的：

    private void initializeEditText()
    {
        final float[] touchY = new float[1];
        touchY[0] = 0; // 记录触点的Y值

        editText.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                editText.getParent().requestDisallowInterceptTouchEvent(true);

                switch (motionEvent.getAction() & MotionEvent.ACTION_MASK)
                {
                    case MotionEvent.ACTION_DOWN:
                        touchY[0] = motionEvent.getY();
                        break;
                    case MotionEvent.ACTION_UP:
                        editText.getParent().requestDisallowInterceptTouchEvent(false);
                        break;
                    default:
                        // 向上滑
                        if (motionEvent.getY() < touchY[0])
                        {
                            // edit text不可以向上滑, 滑动scroll view
                            if (!editText.canScrollVertically(1))
                            {
                                scrollView.smoothScrollBy(0, (int)(touchY[0] - motionEvent.getY()));
                            }
                        }
                        // 向下滑
                        else if (motionEvent.getY() > touchY[0])
                        {
                            // edit text不可以向下滑, 滑动scroll view
                            if (!editText.canScrollVertically(-1))
                            {
                                scrollView.smoothScrollBy(0, (int)(touchY[0] - motionEvent.getY()));
                            }
                        }

                        touchY[0] = motionEvent.getY();
                        break;
                }

                return false;
            }
        });
    }

ps:我发现上面的代码还是有问题的，触摸EditText上下拖动会有抖动，因为滑动ScrollView的同时EditText的位置也变了。修改后的代码如下：

    private void initializeEditText()
    {
        final float[] touchY = new float[1];
        touchY[0] = 0; // 记录触点的Y值

        editText.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {

                switch (motionEvent.getAction() & MotionEvent.ACTION_MASK)
                {
                    case MotionEvent.ACTION_DOWN:
                        editText.getParent().requestDisallowInterceptTouchEvent(true);
                        touchY[0] = motionEvent.getY();
                        break;
                    case MotionEvent.ACTION_UP:
                        editText.getParent().requestDisallowInterceptTouchEvent(false);
                        break;
                    default:
                        // 向上滑
                        if (motionEvent.getY() < touchY[0])
                        {
                            // edit text不可以向上滑, 滑动scroll view
                            if (!editText.canScrollVertically(1))
                            {
                                editText.getParent().requestDisallowInterceptTouchEvent(false);
                            }
                        }
                        // 向下滑
                        else if (motionEvent.getY() > touchY[0])
                        {
                            // edit text不可以向下滑, 滑动scroll view
                            if (!editText.canScrollVertically(-1))
                            {
                                editText.getParent().requestDisallowInterceptTouchEvent(false);
                            }
                        }

                        touchY[0] = motionEvent.getY();
                        break;
                }

                return false;
            }
        });
    }