HorizontalScrollView内部SwipeRefreshLayout

Question

我在我的应用程序中实现了新的SwipeRefreshLayout组件，它可以很好地处理任何垂直视图，比如ListView、GridView和ScrollView。

它在水平视图(如HorizontalScrollView )中的行为非常糟糕。当向右或向左滚动时，SwipeRefreshLayout视图缓存触摸，阻止HorizontalScrollView接收触摸，并开始垂直滚动以执行刷新。

我试着解决这个问题，就像我以前使用ViewPager解决垂直ViewPager问题一样，使用requestDisallowInterceptTouchEvent，但是它没有工作。我还注意到，该方法在原始SwipeRefreshLayout类中被重写，而没有返回超级文件。谷歌的开发者留下了一条评论，"//Nope.“:)

因为SwipeRefreshLayout组件是相对较新的，所以我找不到解决横向滚动问题的解决方案，同时仍然允许swipe刷新视图来跟踪和处理垂直滚动，所以我想我将分享我的解决方案，希望它能节省一两个小时的时间。

Answer 1

我通过扩展SwipeRefreshLayout和重写它的onInterceptTouchEvent来解决这个问题。在里面，我计算用户漫游的X距离是否大于触摸斜度。如果是这样的话，这意味着用户正在水平地滑动，因此我返回false，它允许子视图(在本例中为HorizontalScrollView )获取触摸事件。

public class CustomSwipeToRefresh extends SwipeRefreshLayout {

    private int mTouchSlop;
    private float mPrevX;

    public CustomSwipeToRefresh(Context context, AttributeSet attrs) {
        super(context, attrs);

        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mPrevX = MotionEvent.obtain(event).getX();
                break;

            case MotionEvent.ACTION_MOVE:
                final float eventX = event.getX();
                float xDiff = Math.abs(eventX - mPrevX);

                if (xDiff > mTouchSlop) {
                    return false;
                }
        }

        return super.onInterceptTouchEvent(event);
    }
}

Answer 2

如果您不记住您已经拒绝了ACTION_MOVE事件这一事实，那么如果用户返回到您最初的mPrevX附近，您最终会接受这个事实。

只需添加一个布尔值来记忆它。

public class CustomSwipeToRefresh extends SwipeRefreshLayout {

    private int mTouchSlop;
    private float mPrevX;
    // Indicate if we've already declined the move event
    private boolean mDeclined;

    public CustomSwipeToRefresh(Context context, AttributeSet attrs) {
        super(context, attrs);

        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mPrevX = MotionEvent.obtain(event).getX();
                mDeclined = false; // New action
                break;

            case MotionEvent.ACTION_MOVE:
                final float eventX = event.getX();
                float xDiff = Math.abs(eventX - mPrevX);

                if (mDeclined || xDiff > mTouchSlop) {
                    mDeclined = true; // Memorize
                    return false;
                }
        }

        return super.onInterceptTouchEvent(event);
    }
}

Answer 3

Lior提出的覆盖onInterceptTouchEvent()的解决方案有一个严重的问题。如果内容可滚动容器没有完全滚动起来，那么就不可能在相同的向上滚动手势中激活滑动刷新。实际上，当您开始滚动内部容器并更多地水平移动手指，而不是无意中(默认情况下为8dp )时，建议的mTouchSlop拒绝此姿态。因此，用户必须再次尝试开始刷新。这对用户来说可能很奇怪。

我将原始SwipeRefreshLayout的源代码从支持库提取到我的项目中，并重写了onInterceptTouchEvent()。新的类名是TouchSafeSwipeRefreshLayout

private boolean mPendingActionDown;
private float mInitialDownY;
private float mInitialDownX;
private boolean mGestureDeclined;

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
    ensureTarget();
    final int action = ev.getActionMasked();
    int pointerIndex;

    if (mReturningToStart && action == MotionEvent.ACTION_DOWN) {
        mReturningToStart = false;
    }

    if (!isEnabled() || mReturningToStart || mRefreshing ) {
        // Fail fast if we're not in a state where a swipe is possible
        if (D) Log.e(LOG_TAG, "Fail because of not enabled OR refreshing OR returning to start. "+motionEventToShortText(ev));
        return false;
    }

    switch (action) {
        case MotionEvent.ACTION_DOWN:
            setTargetOffsetTopAndBottom(mOriginalOffsetTop - mCircleView.getTop());
            mActivePointerId = ev.getPointerId(0);

            if ((pointerIndex = ev.findPointerIndex(mActivePointerId)) >= 0) {

                if (mNestedScrollInProgress || canChildScrollUp()) {
                    if (D) Log.e(LOG_TAG, "Fail because of nested content is Scrolling. Set pending DOWN=true. "+motionEventToShortText(ev));
                    mPendingActionDown = true;
                } else {
                    mInitialDownX = ev.getX(pointerIndex);
                    mInitialDownY = ev.getY(pointerIndex);
                }
            }
            return false;

        case MotionEvent.ACTION_MOVE:
            if (mActivePointerId == INVALID_POINTER) {
                if (D) Log.e(LOG_TAG, "Got ACTION_MOVE event but don't have an active pointer id.");
                return false;
            } else if (mGestureDeclined) {
                if (D) Log.e(LOG_TAG, "Gesture was declined previously because of horizontal swipe");
                return false;
            } else if ((pointerIndex = ev.findPointerIndex(mActivePointerId)) < 0) {
                return false;
            } else if (mNestedScrollInProgress || canChildScrollUp()) {
                if (D) Log.e(LOG_TAG, "Fail because of nested content is Scrolling. "+motionEventToShortText(ev));
                return false;
            } else if (mPendingActionDown) {
                // This is the 1-st Move after content stops scrolling.
                // Consider this Move as Down (a start of new gesture)
                if (D) Log.e(LOG_TAG, "Consider this move as down - setup initial X/Y."+motionEventToShortText(ev));
                mPendingActionDown = false;
                mInitialDownX = ev.getX(pointerIndex);
                mInitialDownY = ev.getY(pointerIndex);
                return false;
            } else if (Math.abs(ev.getX(pointerIndex) - mInitialDownX) > mTouchSlop) {
                mGestureDeclined = true;
                if (D) Log.e(LOG_TAG, "Decline gesture because of horizontal swipe");
                return false;
            }

            final float y = ev.getY(pointerIndex);
            startDragging(y);
            if (!mIsBeingDragged) {
                if (D) Log.d(LOG_TAG, "Waiting for dY to start dragging. "+motionEventToShortText(ev));
            } else {
                if (D) Log.d(LOG_TAG, "Dragging started! "+motionEventToShortText(ev));
            }
            break;

        case MotionEvent.ACTION_POINTER_UP:
            onSecondaryPointerUp(ev);
            break;

        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
            mIsBeingDragged = false;
            mGestureDeclined = false;
            mPendingActionDown = false;
            mActivePointerId = INVALID_POINTER;
            break;
    }

    return mIsBeingDragged;
}

请参阅我在Github上的示例项目。