在android中快速滚动时避免滑动刷新

Question

我有一个 ListView 始终启用 fastScroll 并实现 SwipeRefresh。当我向下滑动列表时，它会刷新列表。我的问题是fastScroll。如果列表的第一项可见或在其初始顶部显示，那么如果向下滚动 fastScrollThumb，它会产生 Swipe 效果而不是向下滚动。无论如何/解决方案，如果我按下 fastScrollThumb ，那么它不应该做 Swipe 刷新效果，而是它应该向下滚动作为它的自然行为。

已编辑 我的XML Layout如下：

    <?xml version="1.0" encoding="utf-8"?>
    <android.support.v4.widget.SwipeRefreshLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/swipe_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white" >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <RelativeLayout
            android:id="@+id/buttons_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="10dp"> 

            <ImageView
                android:id="@+id/SubmitButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:background="@drawable/neoo_tab_selector" />

        </RelativeLayout>


        <ListView
            android:id="@id/android:list"
            style="@style/NeeoContactListView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@+id/buttons_layout"
            android:layout_marginTop="10dp" />
    </RelativeLayout>

</android.support.v4.widget.SwipeRefreshLayout>

我的 Logic for onScroll 用于启用/禁用 SwipeRefresh 是：

    getListView().setOnScrollListener(new OnScrollListener() {

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        boolean enable = false;
        if(getListView() != null && getListView().getChildCount() > 0){
            // check if the first item of the list is visible
            boolean firstItemVisible = getListView().getFirstVisiblePosition() == 0;
            // check if the top of the first item is visible
            boolean topOfFirstItemVisible = getListView().getChildAt(0).getTop() == 0;
            // enabling or disabling the refresh layout
            enable = firstItemVisible && topOfFirstItemVisible;
        }
        if(enable){
            enableSwipe();

        }else{
            disableSwipe();

        }
    }
});

Answer 1

我刚刚查看了SwipeRefreshLayout 中的the documentation，我认为他们提到了您正在寻找的内容：

...如果侦听器确定不应该刷新，它必须 致电setRefreshing(false) 取消任何视觉指示 刷新。如果一个活动希望只显示进度动画，它 应该打电话给setRefreshing(true)。禁用手势和进度 动画，在视图上调用setEnabled(false)。

所以你有几个选择，我会首先尝试使用setEnabled() 或setRefreshing()，但要正确使用这些方法，我们首先需要能够检测ListView 是否快速滚动。没有侦听器或任何用于快速滚动的东西，但您可以通过反射获得状态！基于this excellent and seriously underrated answer，我写了一个FastScrollListener，可以像OnScrollListener一样使用：

this.listView.setFastScrollEnabled(true);
this.listView.setOnScrollListener(new FastScrollListener(this.listView) {

    @Override
    protected void onFastScrollStateChanged(AbsListView view, FastScrollState state) {
        // This line disabled the SwipeRefreshLayout  
        // whenever the user is fast scrolling
        swipeRefreshLayout.setEnabled(state != FastScrollState.DRAGGING);
    }

    @Override
    protected void onFastScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

    }
});

如果setEnabled() 不起作用，您也可以尝试调用setRefreshing() 而不是setEnabled()。

这是FastScrollListener的代码：

public abstract class FastScrollListener implements AbsListView.OnScrollListener {

    private final int STATE_DRAGGING;
    private final int STATE_VISIBLE;
    private final int STATE_NONE;

    public enum FastScrollState {
        DRAGGING,
        VISIBLE,
        NONE,
        UNKNOWN
    }

    private FastScrollState fastScrollState = FastScrollState.UNKNOWN;
    private Field stateField;
    private Object mFastScroller;

    public FastScrollListener(AbsListView listView) {
        try {
            final Field fastScrollerField = AbsListView.class.getDeclaredField("mFastScroller");
            fastScrollerField.setAccessible(true);
            mFastScroller = fastScrollerField.get(listView);

            final Field stateDraggingField = mFastScroller.getClass().getDeclaredField("STATE_DRAGGING");
            stateDraggingField.setAccessible(true);
            STATE_DRAGGING = stateDraggingField.getInt(mFastScroller);

            final Field stateVisibleField = mFastScroller.getClass().getDeclaredField("STATE_VISIBLE");
            stateVisibleField.setAccessible(true);
            STATE_VISIBLE = stateVisibleField.getInt(mFastScroller);

            final Field stateNoneField = mFastScroller.getClass().getDeclaredField("STATE_NONE");
            stateNoneField.setAccessible(true);
            STATE_NONE = stateNoneField.getInt(mFastScroller);

            stateField = mFastScroller.getClass().getDeclaredField("mState");
            stateField.setAccessible(true);
            fastScrollState = getFastScrollState();

        } catch (NoSuchFieldException e) {
            throw new IllegalStateException("Could not find required fields for fast scroll detection!", e);
        } catch (IllegalAccessException e) {
            throw new IllegalStateException("Could not find required fields for fast scroll detection!", e);
        }
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        updateFastScrollState(view);
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        updateFastScrollState(view);
        updateFastScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
    }

    private void updateFastScrollState(AbsListView view) {
        if (stateField != null) {
            final FastScrollState state = getFastScrollState();
            if (fastScrollState != state) {
                fastScrollState = state;
                onFastScrollStateChanged(view, state);
            }
        }
    }

    private void updateFastScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        if(fastScrollState == FastScrollState.DRAGGING) {
            onFastScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
        }
    }

    private FastScrollState getFastScrollState() {

        try {
            final int state = stateField.getInt(mFastScroller);

            if (state == STATE_DRAGGING) {
                return FastScrollState.DRAGGING;
            }

            if (state == STATE_VISIBLE) {
                return FastScrollState.VISIBLE;
            }

            if (state == STATE_NONE) {
                return FastScrollState.NONE;
            }

            return FastScrollState.UNKNOWN;
        } catch (IllegalAccessException e) {
            throw new IllegalStateException("Could not read fast scroll state!", e);
        }
    }

    protected abstract void onFastScrollStateChanged(AbsListView view, FastScrollState state);

    protected abstract void onFastScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount);
}

希望对您有帮助，如果您有任何其他问题，请随时提问！

---

编辑：试试这个，但我怀疑它会起作用：

@Override
protected void onFastScrollStateChanged(AbsListView view, FastScrollState state) {
    boolean enable = false;
    if (getListView().getChildCount() > 0) {
        boolean firstItemVisible = getListView().getFirstVisiblePosition() == 0;
        boolean topOfFirstItemVisible = getListView().getChildAt(0).getTop() == 0;
        enable = firstItemVisible && topOfFirstItemVisible;
    }
    refreshLayout.setEnabled(enable);
}

Answer 2

在 api 26 中添加了 recyclerview 中的快速滚动。 https://developer.android.com/topic/libraries/support-library/revisions#26-0-0.

如果你想在 api 26 之前使用它

https://github.com/L4Digital/FastScroll

这个库内置了 fastscroll，它有一个滚动监听器，可以在滚动时禁用刷新视图布局

开发者在这里解决问题：

https://github.com/L4Digital/FastScroll/issues/14