在我的应用程序中,我有一个由 ArrayAdapter 支持的 ListView。在其中,我正在检测 OnScrollListener#onScroll 方法中的事件以查找列表的结尾。我注意到在手机(MyTouch)上,轨迹球和手势/触摸滚动都会触发两次事件。在模拟器上,我通过滚轮和点击和药物滚动获得相同的行为。但是在模拟器中,如果我使用向下箭头按钮滚动该事件只会触发一次。
这是代码:
this.view.setOnScrollListener(new OnScrollListener() {
@Override
public void onScroll(final AbsListView view, final int first,
final int visible, final int total) {
// detect if last item is visible
if (visible < total && (first + visible == total)) {
Log.d("OnScrollListener - end of list", "fvi: " +
first + ", vic: " + visible + ", tic: " + total);
// this line gets called twice
onLastListItemDisplayed(total, visible);
}
}
}
如何抑制或处理这种行为?我只需要一个事件,并尽量不恢复到布尔字段等愚蠢的黑客行为。
据我所知 - 两个事件都有相同的堆栈跟踪
Thread [<3> main] (Suspended (breakpoint at line 116 in SearchResultsView$4))
SearchResultsView$4.onScroll(AbsListView, int, int, int) line: 116
ListView(AbsListView).invokeOnItemScrollListener() line: 655
ListView.arrowScrollImpl(int) line: 2256
ListView.arrowScroll(int) line: 2172
ListView.commonKey(int, int, KeyEvent) line: 1977
ListView.onKeyMultiple(int, int, KeyEvent) line: 1929
KeyEvent.dispatch(KeyEvent$Callback) line: 899
ListView(View).dispatchKeyEvent(KeyEvent) line: 3647
ListView(ViewGroup).dispatchKeyEvent(KeyEvent) line: 744
ListView.dispatchKeyEvent(KeyEvent) line: 1909
FrameLayout(ViewGroup).dispatchKeyEvent(KeyEvent) line: 746
LinearLayout(ViewGroup).dispatchKeyEvent(KeyEvent) line: 746
PhoneWindow$DecorView(ViewGroup).dispatchKeyEvent(KeyEvent) line: 746
PhoneWindow$DecorView.superDispatchKeyEvent(KeyEvent) line: 1708
PhoneWindow.superDispatchKeyEvent(KeyEvent) line: 1197
SearchResultsView(Activity).dispatchKeyEvent(KeyEvent) line: 1967
PhoneWindow$DecorView.dispatchKeyEvent(KeyEvent) line: 1684
ViewRoot.deliverKeyEventToViewHierarchy(KeyEvent, boolean) line: 2329
ViewRoot.handleFinishedEvent(int, boolean) line: 2299
ViewRoot.handleMessage(Message) line: 1621
ViewRoot(Handler).dispatchMessage(Message) line: 99
Looper.loop() line: 123
ActivityThread.main(String[]) line: 4203
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]
Method.invoke(Object, Object...) line: 521
ZygoteInit$MethodAndArgsCaller.run() line: 791
ZygoteInit.main(String[]) line: 549
NativeStart.main(String[]) line: not available [native method]
PS Bug 已创建
PPS 并以非常有用的回复结束The trackball and the touch screen send several motion events very rapidly. This behavior is expected.