向上滚动不适用于Listview中的SwipeRefreshLayout [英] Scroll up does not work with SwipeRefreshLayout in Listview
问题描述
我想实现滚动以使用listView刷新功能.此外，如果列表为空，则在同一布局文件中还会显示其他视图元素.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，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;
}
}
为使SwipeRefreshLayout正常工作，它必须是ListView的直接父级，并且ListView应该是SwipeRefreshLayout的第一个活动子视图./p>
SwipeRefreshLayout的文档说ListView应该是唯一的子级，但是只要有一个以上的子级(只要ListView是第一个)就可以.例如，这意味着，如果您使用的适配器带有空"视图，则SwipeRefreshLayout可以正常工作.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，则SwipeRefreshLayout将可以正常工作，并且您不需要其他答案中列出的任何解决方法.
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>
因此SwipeRefreshLayout选择FrameLayout作为其目标"，并且其默认canChildScrollUp()实现始终返回false.一旦我将SwipeRefreshLayout移到Fragment中，一切就开始正常工作.
<FrameLayout>
<SwipeRefreshLayout> )
<ListView/> \ fragment
<TextView/> /
</SwipeRefreshLayout> )
</FrameLayout>
I want to implement scroll to refresh functionality with a listView. Also there are other view elements in the same layout file which are displayed if the list is empty. Here is my layout file. The problem is that when I scroll down and then try to scroll up, instead of scrolling all the way to the top and then refreshing it just refreshes there and scroll up is not working.
<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>
This is my onScroll method.
@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;
}
}
In order for SwipeRefreshLayout to work, it needs to be the direct parent of your ListView, and the ListView should be the first active child view of the SwipeRefreshLayout.
The documentation for SwipeRefreshLayout says that the ListView should be the only child, but it is okay if it has more than one child as long as the ListView is first. This means, for instance, that SwipeRefreshLayout will work fine if you are using an adapter with a view for "empty". For example:
<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>
If you can manage this sort of layout, then SwipeRefreshLayout will work fine and you won't need any of the workarounds listed in other answers.
My own problem was that that I was loading my ListView as a Fragment, so I actually had:
<SwipeRefreshLayout>
<FrameLayout> )
<ListView/> \ fragment
<TextView/> /
</FrameLayout> )
</SwipeRefreshLayout>
So the SwipeRefreshLayout was choosing the FrameLayout as it's "target" and its default canChildScrollUp() implementation was always returning false. Once I moved the SwipeRefreshLayout inside the Fragment, everything started working correctly.
<FrameLayout>
<SwipeRefreshLayout> )
<ListView/> \ fragment
<TextView/> /
</SwipeRefreshLayout> )
</FrameLayout>
这篇关于向上滚动不适用于Listview中的SwipeRefreshLayout的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
