Android ListView setSelection() 似乎不起作用
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Android ListView setSelection() does not seem to work
提问by alkar
I have a ListActivitythat implements onListItemClick()and calls a doSomething()function of the class. The latter contains l.setSelection(position)where lis the ListViewobject.
我有一个ListActivity实现onListItemClick()并调用doSomething()类的函数。后者包含l.setSelection(position)其中l是ListView对象。
Now there is a onClickListener()listening for a button click that perfoms some actions and that too calls doSomething().
现在可以onClickListener()监听执行某些操作的按钮单击，并且也调用doSomething().
In the first case, the selected item get positioned appropriately, but in the latter, nothing happens.
在第一种情况下，所选项目得到适当定位，但在后一种情况下，什么也没有发生。
Any clues about this strange behaviour and how I might make it work?
关于这种奇怪行为的任何线索以及我如何使它起作用？
回答by meizilp
maybe you need to use function:
也许你需要使用功能：
ListView.setItemChecked(int position, boolean checked);
回答by AlexD
use requestFocusFromTouch()before calling setSelection()method
requestFocusFromTouch()在调用setSelection()方法之前使用
回答by mr_hyde
I know this is an old question but I just had a similar problem that I solved in this way:
我知道这是一个老问题，但我刚刚遇到了一个类似的问题，我以这种方式解决了：
mListView.clearFocus();
mListView.post(new Runnable() {
@Override
public void run() {
mListView.setSelection(index);
}
});
回答by kostmo
回答by CommonsWare
setSelection()does not necessarily have visual impact. The selection bar only appears if you use the D-pad/trackball to navigate the list. If you tap on the screen to click something, the selection bar appears briefly and vanishes.
setSelection()不一定有视觉冲击。选择栏仅在您使用方向键/轨迹球导航列表时出现。如果您点击屏幕以单击某些内容，则选择栏会短暂出现并消失。
Hence, setSelection()will only have a visual impact if the activity is not in touch mode (i.e., the last thing the user did was use the D-pad/trackball).
因此，setSelection()只有在活动未处于触摸模式时才会产生视觉影响（即，用户所做的最后一件事是使用方向键/轨迹球）。
I am not 100% certain this explains your phenomenon given the description you provided, but I figured it is worth a shot...
鉴于您提供的描述，我不能 100% 确定这可以解释您的现象，但我认为值得一试......
回答by Bobs
If you use an Adapter for your ListView add this code to your adapter:
如果您为 ListView 使用适配器，请将此代码添加到您的适配器：
public class MyAdapter extends
ArrayAdapter<MyClass> {
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater inflator = (LayoutInflater) getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowView = inflator.inflate(R.layout.my_adapter, null);
} else {
rowView = (View) convertView;
}
//...
// set selected item
LinearLayout ActiveItem = (LinearLayout) rowView;
if (position == selectedItem)
{
ActiveItem
.setBackgroundResource(R.drawable.background_dark_blue);
// for focus on it
int top = (ActiveItem == null) ? 0 : ActiveItem.getTop();
((ListView) parent).setSelectionFromTop(position, top);
}
else
{
ActiveItem
.setBackgroundResource(R.drawable.border02);
}
}
private int selectedItem;
public void setSelectedItem(int position) {
selectedItem = position;
}
}
In your Activity:
在您的活动中：
myAdapter.setSelectedItem(1);
回答by Nick
I have an very large Request with Webcontent. When I used the code in onCreateView the Listview wasnt even finished loading. I put it in onPostExecute of my AsyncTask.
我有一个非常大的 Webcontent 请求。当我在 onCreateView 中使用代码时，Listview 甚至还没有完成加载。我把它放在我的 AsyncTask 的 onPostExecute 中。
//Get last position in listview
if (listView != null && scrollPosition != 0) {
listView.clearFocus();
listView.requestFocusFromTouch();
listView.post(new Runnable() {
@Override
public void run() {
listView.setItemChecked(scrollPosition, true);
listView.setSelection(scrollPosition);
}
});
}
Dont forget to set the item checked in on Click ;)
不要忘记设置在 Click 上签入的项目；)
回答by MaInStReAm
For me calling
给我打电话
listView.notifyDataSetChanged();
listView.requestFocusFromTouch();
and then
进而
listView.setSelection(position);
solved the issue.
解决了这个问题。
if you do that in a runnable it works without calling requestFocusFromTouch(), but the old position of the ListView is showen for a sekound.
如果您在可运行对象中执行此操作，则无需调用 requestFocusFromTouch() 即可工作，但会显示 ListView 的旧位置以用于 sekound。
回答by TaoZang
Maybe you should use the smoothScrollToPosition(int position) method of ListView
也许你应该使用 ListView 的 smoothScrollToPosition(int position) 方法
回答by Courysky
You can try 2 ways like these:
Solution A:
您可以尝试以下 2 种方法：
解决方案 A：
mListView.post(new Runnable() {
@Override
public void run() {
if (null != mListView) {
mListView.clearFocus();
mListView.requestFocusFromTouch();
mListView.setSelection(0);
}
}
});
In some complicated situation, this solution will bring some new problems in Android 8.x.
Besides it may cause unexpected onFocusChange().
在一些复杂的情况下，这种解决方案会在Android 8.x 中带来一些新的问题。
此外它可能会导致意外的 onFocusChange()。
Solution B: Define a custom view extends ListView. Override method handleDataChanged().Then setSelection(0). In CustomListView:
方案B：定义一个自定义视图扩展ListView。覆盖方法handleDataChanged().然后setSelection(0)。在自定义列表视图中：
@Override
protected void handleDataChanged() {
super.handleDataChanged();
if (null != mHandleDataChangedListener){
mHandleDataChangedListener.onChanged();
}
}
HandleDataChangedListener mHandleDataChangedListener;
public void setHandleDataChangedListener(HandleDataChangedListener handleDataChangedListener) {
this.mHandleDataChangedListener = handleDataChangedListener;
}
public interface HandleDataChangedListener{
void onChanged();
}
In activity:
在活动中：
mListView.setHandleDataChangedListener(new CustomListView.HandleDataChangedListener() {
@Override
public void onChanged() {
mListView.setHandleDataChangedListener(null);
mListView.setSelection(0);
}
});
mAdapter.notifyDataSetChanged();
Ok, That's it.
好的，就是这样。
