问题
I\'m facing some difficults when I try to use the performItemClick funcion of the ListView.
All I want to do is to perform a click programatically in the first item of the list.
How can I do that? I looked up that function in the documentation, but I didn\'t really understand its parameters.
I tried something like:
myListView.performItemClick(myListView.getChildAt(0), 0, myListView.getChildAt(0).getId());
But it didn\'t work (myListView.getChildAt(0) returns null)
Thank you in advance!
回答1:
mList.performItemClick(
mList.getAdapter().getView(mActivePosition, null, null),
mActivePosition,
mList.getAdapter().getItemId(mActivePosition));
Where mActivePosition is your click position! All the best! :)
回答2:
This worked for me.
listView.performItemClick(
listView.getAdapter().getView(position, null, null), position, position);
use the adapter to get the view for the position of the item. The other 2 parameters I didn't want so I left them null. Leaving convertView null causes the adapter to render a new view. It's a performance issue but since this is only happening once in a while it wont have much effect. I don't need to specify the parent for anything because I'm not using it.
position is just the spot where your item is located. Additionally these 2 lines of code before your performItemClick create the illusion of having the list item selected. They also ensure the appropriate item is on the screen.
listView.requestFocusFromTouch();
listView.setSelection(position);
回答3:
This works best for me. Run this on the main thread.
new Handler().post(new Runnable() {
@Override
public void run() {
mList.performItemClick(
mList.getChildAt(mActivePosition),
mActivePosition,
mList.getAdapter().getItemId(mActivePosition));
}
});
This is similar to Arun Jose's answer, but it will queue a message to the main thread to give the ListView some time to initiate.
回答4:
I tried the code below and it worked.
getListView().performItemClick(null, 0, getListAdapter().getItemId(0));
The first parameter (view) can be null.
回答5:
I went with
listView.getAdapter().getView(position, null, null).performClick();
回答6:
this may be old but this may help :
lvList.performItemClick(null, index, lvList.getItemIdAtPosition(index) );
NOTE : the first param is null and will still work, if you have a custom adapter, convertView will be filled with custom layout and view and such.
-cheers / happy codings.
回答7:
mList.performItemClick(
mList.getChildAt(mActivePosition),
mActivePosition,
mList.getAdapter().getItemId(mActivePosition));
where mActivePosition is the position of the child view in List View.
回答8:
Using the code @sulal proposed, you may place it in onLoadFinished, if you use a LoaderManager. Eg something like
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
//....
// mSelectedId keeps the currently selected id
// INVID is an invalid value
if (mSelectedId == INVID) { // nothing selected
// sulal's code
new Handler().post(new Runnable() {
@Override
public void run() {
mList.performItemClick(
mList.getChildAt(mActivePosition),
mActivePosition,
mList.getAdapter().getItemId(mActivePosition));
mSelectedId = mList.getAdapter().getItemId(mActivePosition);
}
});
}
mActivePosition may be 0 (ie position on the first item) or a position kept during eg onPause
回答9:
At Firstly I tried to use this code in my Fragment(Master/Detail -> NameListFragment)
getListView().performItemClick(null, 0, getListView().getAdapter().getItemId(0));
But it didn't work. When I did @Override onStart() method in fragment and I moved my code to onStart(). After that it works properly for me.
回答10:
If you are working on a unit test case. Try to use getInstrumentation().waitForIdleSync(), to wait the list be loaded, and extend the ActivityInstrumentationTestCase2 See this answer.
回答11:
I just meet this freak problem today , and I try me best to deal with it. My condition is , when I first init the layout , I need make some item checked. But when I use gridView.getChildAt(position) , always return null. I met this problem before , caused by Not finishing drawing layout . So I send a post message . handler.postDelayed( .. , ..) , It works. Thanks who motion this Exception.
回答12:
This work for me If you would get weird result when using getView, this is because the list item you want does not exist within visible parts. Use below:
private View getViewFromAdapterByPosition(int position, ListView listView)
{
View view;
int firstVisiblePos = listView.getFirstVisiblePosition();
int lastVisiblePos = listView.getLastVisiblePosition();
if (position < firstVisiblePos || position > lastVisiblePos) {
view = listView.getAdapter().getView(position, null, listView);
} else {
view = listView.getChildAt(position - firstVisiblePos);
}
return view;
}
And then,
listView.performItemClick(getViewFromAdapterByPosition(index, listView), index, 0);
回答13:
When using Listview (simple array adapter or custom adapter) define listview and other finally make perform click.
For example:
//At onCreate function:
lv = (ListView) findViewById(R.id.listView);
lv.setAdapter(new CustomAdapter(List_item.this, list, images));
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// on click function works
}
}
int position = 0;
lv.performItemClick(lv.getAdapter().getView(position, null, null), position, lv.getAdapter().getItemId(position));
Note: After creating the setOnItemClickListener only you should call perform click. Otherwise, it will not correctly.
回答14:
Try this one:
public static boolean performClicKOnLisViewFromIndex(ListView listView, int index){
if(listView != null){
if(listView.getAdapter()!= null && listView.getAdapter().getCount() >0 && listView.getAdapter().getCount() > index ){
listView.performItemClick(
listView.getAdapter().getView(index, null, null),
index, listView.getItemIdAtPosition(index));
return true;
}
}
return false;
}
回答15:
The performClick is probably called before listview was filled, put breakpoint in getView and on performItemClick and check wich is called first
回答16:
getListView().performItemClick(null, 0, 0) did the trick for me (for position 0).
回答17:
Dropping Some Experience.
using listview1.performItemClick, will also trigger your listview1.OnItemClickListener if you are using the listener with same listview in your code.
Hope It helps
回答18:
If you would get weird result when using getView, this is because the list item you want does not exist within visible parts. Use below:
private View getViewFromAdapterByPosition(int position, ListView listView)
{
View view;
int firstVisiblePos = listView.getFirstVisiblePosition();
int lastVisiblePos = listView.getLastVisiblePosition();
if (position < firstVisiblePos || position > lastVisiblePos) {
view = listView.getAdapter().getView(position, null, listView);
} else {
view = listView.getChildAt(position - firstVisiblePos);
}
return view;
}
And then,
listView.performItemClick(getViewFromAdapterByPosition(index, listView), index, 0);
回答19:
This works for me:
listview.getSelectedView().performClick();
回答20:
This worked for me:
listView.getAdapter().getView(1, null, null).performClick();
回答21:
This is from Begining Android Games. It creates a simple list of items which you can click to open a new activity. Each list item of course, would have to also be added to the AndroidManifest.xml as a separate activity with a .ListItem# name.
public class MainActivity extends ListActivity {
String tests[] = { "ListItem1",
"ListItem2",
"ListItem3",
"ListItem4"};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, tests));
}
@Override
protected void onListItemClick(ListView list, View view, int position, long id) {
super.onListItemClick(list, view, position, id);
String testName = tests[position];
try {
Class<?> classInstance = Class.forName("your.package.name." + testName);
Intent intent = new Intent(this, classInstance);
startActivity(intent);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
来源：https://stackoverflow.com/questions/8094268/android-listview-performitemclick