我希望在列表视图的向上滚动时隐藏操作栏,并在列表视图的向下滚动时再次显示操作栏。是否有任何方法可以检测listview的上下滚动?如果是,那么请提供一些参考。
任何帮助或指导都将受到赞赏。
答案 0 :(得分:4)
也许你可以尝试以下方法来完成这项工作:
listView.setOnScrollListener(new OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) { }
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if(listView.getFirstVisiblePosition() == 0)
getActionBar().show();
else
getActionBar().hide();
}
});
答案 1 :(得分:2)
这是来自Google IO 2014的Android应用。提供一个很好的向上或向下滚动检测,以在滚动一定量的行后显示/隐藏工具栏。
private int mActionBarAutoHideSensivity = 0;
private int mActionBarAutoHideMinY = 0;
private int mActionBarAutoHideSignal = 0;
private boolean mActionBarShown = true;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
// ...
ListView listView = (ListView) contentView.findViewById(R.id.listView);
initActionBarAutoHide();
listView.setOnScrollListener(new ListViewOnScrollListener());
// ...
}
private void initActionBarAutoHide() {
mActionBarAutoHideMinY = getResources().getDimensionPixelSize(R.dimen.action_bar_auto_hide_min_y); //152dp
mActionBarAutoHideSensivity = getResources().getDimensionPixelSize(R.dimen.action_bar_auto_hide_sensivity); //48dp
}
public class ListViewOnScrollListener implements OnScrollListener {
final static int ITEMS_THRESHOLD = 3;
int lastFvi = 0;
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
onMainContentScrolled(firstVisibleItem <= ITEMS_THRESHOLD ? 0 : Integer.MAX_VALUE,
lastFvi - firstVisibleItem > 0 ? Integer.MIN_VALUE :
lastFvi == firstVisibleItem ? 0 : Integer.MAX_VALUE
);
lastFvi = firstVisibleItem;
}
}
private void onMainContentScrolled(int currentY, int deltaY) {
if (deltaY > mActionBarAutoHideSensivity) {
deltaY = mActionBarAutoHideSensivity;
} else if (deltaY < -mActionBarAutoHideSensivity) {
deltaY = -mActionBarAutoHideSensivity;
}
if (Math.signum(deltaY) * Math.signum(mActionBarAutoHideSignal) < 0) {
// deltaY is a motion opposite to the accumulated signal, so reset signal
mActionBarAutoHideSignal = deltaY;
} else {
// add to accumulated signal
mActionBarAutoHideSignal += deltaY;
}
boolean shouldShow = currentY < mActionBarAutoHideMinY || (mActionBarAutoHideSignal <= -mActionBarAutoHideSensivity);
autoShowOrHideActionBar(shouldShow);
}
protected void autoShowOrHideActionBar(boolean show) {
if (show == mActionBarShown) {
return;
}
mActionBarShown = show;
if (show) {
onScrollingUp();
} else {
onScrollingDown();
}
}
public void onScrollingUp() {
// ...
}
public void onScrollingDown() {
// ...
}
答案 2 :(得分:1)
API提供了这样的方法,但是它们受到保护,因此我认为最好的做法是创建包装类(扩展ScrollView)并公开这些方法,特别是onScrollChanged
和onOverScroll
。
您可以查看以下问题,了解如何执行此操作:
答案 3 :(得分:1)
在android listview上检测向上/向下滚动的简单方法
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount){
if(prevVisibleItem != firstVisibleItem){
if(prevVisibleItem < firstVisibleItem)
//ScrollDown
else
//ScrollUp
prevVisibleItem = firstVisibleItem;
}
别忘了
yourListView.setOnScrollListener(yourScrollListener);