在底部列表中的列表视图

我遇到了一个问题，我有一个简单的ListView在BottomSheet和ListView有足够的项目来填补屏幕和滚动更多。

当我向下滚动时，一切似乎都有效，但是当我试图向上滚动时，它正在滚动BottomSheet本身并关闭视图，而不仅仅是滚动ListView。

我在一段时间后找到了一个解决方案，因为我在这里找不到它，我想我应该把它贴在这里。

解决方案是这样扩展ListView:

public class BottomSheetListView extends ListView {
    public BottomSheetListView (Context context, AttributeSet p_attrs) {
        super (context, p_attrs);
    }
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return true;
    }
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (canScrollVertically(this)) {
            getParent().requestDisallowInterceptTouchEvent(true);
        }
        return super.onTouchEvent(ev);
    }
    public boolean canScrollVertically (AbsListView view) {
        boolean canScroll = false;
        if (view !=null && view.getChildCount ()> 0) {
            boolean isOnTop = view.getFirstVisiblePosition() != 0 || view.getChildAt(0).getTop() != 0;
            boolean isAllItemsVisible = isOnTop && view.getLastVisiblePosition() == view.getChildCount();
            if (isOnTop || isAllItemsVisible) {
                canScroll = true;
            }
        }
        return  canScroll;
    }
}

然后在布局文件bottom_sheet_view.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <com.mypackage.name.BottomSheetListView
        android:id="@+id/listViewBtmSheet"
        android:divider="@color/colorPrimary"
        android:dividerHeight="1dp"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="0dp" />
</LinearLayout>

最后，在你的Activity/Fragment:

BottomSheetDialog dialog = new BottomSheetDialog(context);
dialog.setContentView(R.layout.bottom_sheet_view);
BottomSheetListView listView = (BottomSheetListView) dialog.findViewById(R.id.listViewBtmSheet);
// apply some adapter - add some data to listview
dialog.show();

这将提供一个BottomSheet，是完全工作与ListView滚动

如果您不想扩展ListView:

//in onCreate
_listView.setOnTouchListener(new ListView.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                int action = event.getAction();
                switch (action) {
                    case MotionEvent.ACTION_DOWN:
                        // Disallow NestedScrollView to intercept touch events.
                        v.getParent().requestDisallowInterceptTouchEvent(true);
                        break;
                    case MotionEvent.ACTION_UP:
                        // Allow NestedScrollView to intercept touch events.
                        v.getParent().requestDisallowInterceptTouchEvent(false);
                        break;
                }
                // Handle ListView touch events.
                v.onTouchEvent(event);
                return true;
            }
        });

从版本22.1.0开始，您可能想要尝试setNestedScrollingEnabled=true

如果此属性设置为true，则允许视图与当前层次结构中兼容的父视图启动嵌套滚动操作。如果这个视图没有实现嵌套滚动，这将没有效果。当嵌套滚动正在进行时禁用嵌套滚动会导致嵌套滚动停止。

参考Google API

这是正确的带有touch事件处理的列表视图自定义类

public class BottomSheetListView extends ListView
{
    public BottomSheetListView(Context context, AttributeSet p_attrs)
    {
        super(context, p_attrs);
    }
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev)
    {
        if (canScrollVertically(this))
        {
            getParent().requestDisallowInterceptTouchEvent(true);
        }
        return super.onInterceptTouchEvent(ev);
    }
    @Override
    public boolean onTouchEvent(MotionEvent ev)
    {
        if (canScrollVertically(this))
        {
            getParent().requestDisallowInterceptTouchEvent(true);
        }
        return super.onTouchEvent(ev);
    }
    public boolean canScrollVertically(AbsListView view)
    {
        boolean canScroll = false;
        if (view != null && view.getChildCount() > 0)
        {
            boolean isOnTop = view.getFirstVisiblePosition() != 0 || view.getChildAt(0).getTop() != 0;
            boolean isAllItemsVisible = isOnTop && view.getLastVisiblePosition() == view.getChildCount();
            if (isOnTop || isAllItemsVisible)
            {
                canScroll = true;
            }
        }
        return canScroll;
    }
}

public class BottomSheetListView extends ListView {
    public BottomSheetListView(Context context, AttributeSet attributeSet) {
        super(context, attributeSet);
    }
    @Override
    public boolean onInterceptTouchEvent(MotionEvent motionEvent) {
        View view = (View) getChildAt(getChildCount() - 1);
        int diffBottom = (view.getBottom() - (getHeight() + getScrollY()));
        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
            if (diffBottom == 0) {
                return false;
            }
        }
         /*//Need more improvement on this logic. Do not uncomment
        int diffTop = (view.getTop() - (getHeight() + getScrollY()));
        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
            if (diffTop < 0) {
                return true;
            }
        }*/
        return super.onInterceptTouchEvent(motionEvent);
    }
    @Override
    public boolean onTouchEvent(MotionEvent motionEvent) {
        if (canScrollVertically(this)) {
            getParent().requestDisallowInterceptTouchEvent(true);
        }
        return super.onTouchEvent(motionEvent);
    }
    public boolean canScrollVertically(AbsListView absListView) {
        boolean canScroll = false;
        if (absListView != null && absListView.getChildCount() > 0) {
            boolean isOnTop = absListView.getFirstVisiblePosition() != 0 || absListView.getChildAt(0).getTop() != 0;
            boolean isAllItemsVisible = isOnTop && getLastVisiblePosition() == absListView.getChildCount();
            if (isOnTop || isAllItemsVisible)
                canScroll = true;
        }
        return canScroll;
    }
}

我知道这是一个有点hack，但它为我工作，甚至listview是可选择的。正如我们所知道的，当底部表单改变它的状态时，它可以被捕获在它的监听器中，所以如果listview没有触摸顶部，不要让它改变状态，因此touch事件将被传递给listview，并将像它一样工作。

    mBottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback(){
@Override
public void onStateChanged(View bottomSheet, int newState) {
        if (newState == BottomSheetBehavior.STATE_DRAGGING && !listIsAtTop()){
            mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
        }
}
@Override
public void onSlide(View bottomSheet, float slideOffset) {}});
public boolean listIsAtTop()   {
    if(tripListView.getChildCount() == 0) return true;
    return (tripListView.getChildAt(0).getTop() == 0 && tripListView.getFirstVisiblePosition() ==0);
}

将android:nestedScrollingEnabled设置为true布局为ListView属性或listView.setNestedScrollingEnabled(true)在java .

我已经尝试了这里描述的嵌套ListViews，但是当触及ListView时，它们不允许展开/折叠底表。下面是我的解决方案，当你向上滚动，ListView不能向上滚动，底部表格将展开，当你向下滚动，ListView不能，BottomSheet将折叠。

public class NestedListView extends ListView {
    private boolean mIsBeingDragged = false;
    private float mLastMotionY;
    public NestedListView(final Context context, final AttributeSet attrs) {
        super(context, attrs);
    }
    public NestedListView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_DOWN: {
                if (canScrollDown() || canScrollUp()) {
                    final ViewParent parent = getParent();
                    if (parent != null) {
                        parent.requestDisallowInterceptTouchEvent(true);
                    }
                }
                break;
            }
        }
        return super.onInterceptTouchEvent(event);
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        final float y = event.getRawY();
        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_MOVE: {
                if (!mIsBeingDragged) {
                    final float deltaY = mLastMotionY - y;
                    mIsBeingDragged = (deltaY > 0 && canScrollDown())
                        || (deltaY < 0 && canScrollUp());
                    if (mIsBeingDragged) {
                        final ViewParent parent = getParent();
                        if (parent != null) {
                            parent.requestDisallowInterceptTouchEvent(true);
                        }
                    } else {
                        final ViewParent parent = getParent();
                        if (parent != null) {
                            parent.requestDisallowInterceptTouchEvent(false);
                        }
                        return false;
                    }
                }
            }
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                mIsBeingDragged = false;
                break;
        }
        mLastMotionY = y;
        return super.onTouchEvent(event);
    }
    public boolean canScrollUp() {
        final int childCount = getChildCount();
        if (childCount == 0) {
            return false;
        }
        final int firstPosition = getFirstVisiblePosition();
        final int firstTop = getChildAt(0).getTop();
        return firstPosition > 0 || firstTop < getListPaddingTop();
    }
    public boolean canScrollDown() {
        final int childCount = getChildCount();
        if (childCount == 0) {
            return false;
        }
        final int firstPosition = getFirstVisiblePosition();
        final int lastBottom = getChildAt(childCount - 1).getBottom();
        final int lastPosition = firstPosition + childCount;
        return lastPosition < getCount() || lastBottom > getHeight() - getListPaddingBottom();
    }
}

我想我有点晚了，但请使用嵌套滚动启用true在你的listview它会帮助你向下滚动的问题。

<ListView
android:id="@+id/rv_jobs_offers"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:nestedScrollingEnabled="true"
android:layout_marginTop="@dimen/dimens_20"/>

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