我想用listView实现滚动刷新功能。此外,如果列表为空,则在同一布局文件中还有其他视图元素。这是我的布局文件。问题是,当我向下滚动然后尝试向上滚动时,而不是一直滚动到顶部然后刷新它只是在那里刷新并向上滚动不起作用。
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/swipe_container"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="64dp"
android:paddingLeft="16dp"
android:paddingRight="16dp" >
<ImageView
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:src="@drawable/inbox_empty" />
<TextView
android:id="@+id/noEventsText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="16dp"
android:layout_toRightOf="@+id/noEventsIcon" />
<View
android:id="@+id/divider"
android:layout_width="match_parent"
android:layout_height="1px"
android:layout_alignParentBottom="true"
android:layout_marginLeft="4dp"
android:layout_marginRight="4dp"
android:background="@color/dividerOnBlack" />
</RelativeLayout>
<ListView
android:id="@+id/list_items"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:cacheColorHint="@android:color/transparent"
android:choiceMode="multipleChoice"
android:descendantFocusability="afterDescendants"
android:divider="@android:color/transparent"
android:dividerHeight="0px"
android:scrollbars="none" />
</LinearLayout>
</android.support.v4.widget.SwipeRefreshLayout>
这是我的onScroll方法。
@Override
public void onScroll(AbsListView view,int firstVisibleItem,int visibleItemCount,int totalItemCount) {
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount) {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0) { this.loading = true; }
}
// If it's still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount)) {
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
// If reverse then the firstVisibleItem is calculated wrong
if (reverse) {
firstVisibleItem = totalItemCount - firstVisibleItem;
}
// If it isn't currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
if (!loading && (totalItemCount - visibleItemCount)<=(firstVisibleItem + visibleThreshold)) {
onLoadMore(currentPage + 1, totalItemCount);
loading = true;
}
}
为了使SwipeRefreshLayout工作,它需要是ListView的直接父级,ListView应该是SwipeRefreshLayout的第一个活动子视图。
SwipeRefreshLayout的文档说ListView应该是唯一的子节点,但只要ListView是第一个,它就可以有多个子节点。这意味着,例如,如果您使用视图为“empty”的适配器,SwipeRefreshLayout将正常工作。例如:
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/swipe_refresh"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".NearbyJobsActivity$PlaceholderFragment">
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@color/list_divider"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_row_selector" />
<TextView
android:id="@android:id/empty"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" />
</android.support.v4.widget.SwipeRefreshLayout>
如果您可以管理这种布局,那么SwipeRefreshLayout将正常工作,您将不需要在其他答案中列出的任何变通方法。
我自己的问题是我将ListView作为片段加载,所以我实际上有:
<SwipeRefreshLayout>
<FrameLayout> )
<ListView/> \ fragment
<TextView/> /
</FrameLayout> )
</SwipeRefreshLayout>
所以SwipeRefreshLayout选择了FrameLayout作为它的“目标”,它的默认canChildScrollUp()
实现总是返回false。一旦我在Fragment中移动SwipeRefreshLayout,一切都开始正常工作。
<FrameLayout>
<SwipeRefreshLayout> )
<ListView/> \ fragment
<TextView/> /
</SwipeRefreshLayout> )
</FrameLayout>
我有同样的问题并解决了它:
listView = (ListView) findViewById(R.id.listView);
listView.setOnScrollListener(new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
if (listView.getChildAt(0) != null) {
swipeRefreshLayout.setEnabled(listView.getFirstVisiblePosition() == 0 && listView.getChildAt(0).getTop() == 0);
}
}
});
创建一个像这样的布局。
<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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="@string/guides_no_results"
android:id="@+id/empty_view"
android:gravity="center"
android:padding="16dp"
android:fontFamily="sans-serif-light"
android:textSize="20sp"
android:visibility="gone"/>
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:drawSelectorOnTop="true"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:id="@+id/guides_list" />
</LinearLayout>
如果您按原样使用此功能,则每次在该视图中向上滚动时,SwipeRefreshLayout都会触发并更新,从而使您的应用无法在列表中向上滚动。
这里的技巧是手动连接ListView的OnScrollListener。您只需检查显示的第一行是否与第一个最顶层位置匹配,然后启用SwipeRefreshLayout。否则,禁用它。
guidesList.setOnScrollListener(new AbsListView.OnScrollListener()
{
@Override
public void onScrollStateChanged(AbsListView view, int scrollState)
{
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
int topRowVerticalPosition = (guidesList == null || guidesList.getChildCount() == 0) ? 0 : guidesList.getChildAt(0).getTop();
swipeContainer.setEnabled(firstVisibleItem == 0 && topRowVerticalPosition >= 0);
}
});
有了这个小片段,现在它完美无缺。
快乐的编码!
来源 - http://nlopez.io/swiperefreshlayout-with-listview-done-right/
自己实现SwipeRefreshLayout并以这种方式覆盖canChildScrollUp:
@Override
public boolean canChildScrollUp() {
if (scrollView != null)
return scrollView.canScrollVertically(-1);
return false;
}
只需替换ScrollView的任何子类。
我有一个类似的问题,我的SwipeRefreshLayout
的孩子是一个FrameLayout
有一个TextView
和ListView
作为孩子,当我向上滚动ListView
它会尝试刷新。
我通过使用自定义FrameLayout
修复它来覆盖canScrollVertically()
方法
包com.wi.director.ui.common;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.FrameLayout;
/**
* Created by devansh on 9/22/15.
*/
public class FrameLayoutForSwipeRefresh extends FrameLayout {
public FrameLayoutForSwipeRefresh(Context context) {
super(context);
}
public FrameLayoutForSwipeRefresh(Context context, AttributeSet attrs) {
super(context, attrs);
}
public FrameLayoutForSwipeRefresh(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public boolean canScrollVertically(int direction) {
if (super.canScrollVertically(direction)) {
return true;
}
int cc = getChildCount();
for (int i = 0; i < cc; i++) {
if (getChildAt(i).canScrollVertically(direction)) {
return true;
}
}
return false;
}
}
如果SwipeRefreshLayout
启用firstVisibleItem
更简单,如果不启用则禁用:
yourList.setOnScrollListener(new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
yourSwipeRefreshLayout.setEnabled(firstVisibleItem == 0);
}
});
gridView.setOnScrollListener(new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState)
{
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
if (gridView.getChildAt(0) != null) {
mrefreshlayout.setEnabled(gridView.getFirstVisiblePosition() == 0 && gridView.getChildAt(0).getTop() == 0);
}
}
});
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/swiperefreshlayout"
android:layout_height="match_parent"
android:layout_width="match_parent">
<LinearLayout
android:background="#ffffff"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<GridView
android:background="#ffffff"
android:gravity="center"
android:verticalSpacing="2dp"
android:horizontalSpacing="2dp"
android:numColumns="2"
android:id="@+id/grid_view"
android:animateLayoutChanges="true"
android:overScrollMode="always"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<TextView
android:id="@+id/nofieldtv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@+id/adlayout"
android:textColor="#000000"
android:gravity="center"
android:visibility="gone"
android:textSize="16sp"
android:layout_below="@+id/headerLayout"
android:layout_marginTop="2dp">
</TextView>
</LinearLayout>
</android.support.v4.widget.SwipeRefreshLayout>
基本上,我们想滚动可滚动的东西。我们可以将所有视图放在ScrollView中。
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
</LinearLayout>
</ScrollView>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
但滚动ListView可能需要一些修改 - wrap_content ListView