runOnUiThread in fragment
AndroidAndroid FragmentsAndroid ActivityAndroid Problem Overview
I'm trying to convert an Activity to fragment. The error mark on runOnUiThread
.
on the past:
> GoogleActivityV2 extends from Activity. runOnUiThread in class > ExecuteTask. class ExecuteTask nested on activity.
(Run ok) now :
> GoogleActivityV2 extends from Fragment. runOnUiThread in class > ExecuteTask. class ExecuteTask nested on activity. (Error on > runOnUiThread)
here is my code
public class GoogleActivityV2 extends SherlockMapFragment implements OnMapClickListener , OnMapLongClickListener , OnCameraChangeListener , TextWatcher {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View rootView = inflater.inflate(R.layout.activity_googlev2, container, false);
Init();
adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_dropdown_item_1line);
textView = (AutoCompleteTextView) getView().findViewById(R.id.autoCompleteTextView1);
return rootView;
}
public void onCameraChange(CameraPosition arg0){
// TODO Auto-generated method stub
}
public void onMapLongClick(LatLng arg0){
llLoc = arg0;
stCommand = "onTouchEvent";
lp = new ExecuteTask();
lp.execute();
}
public void onMapClick(LatLng arg0){
// TODO Auto-generated method stub
}
class ExecuteTask extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute(){
super.onPreExecute();
if(stCommand.compareTo("AutoCompleteTextView") != 0) {
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage(Html.fromHtml("<b>Search</b><br/>Loading ..."));
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
}
protected String doInBackground(String ... args){
do something
return null;
}
@Override
protected void onPostExecute(String file_url){
if(stCommand.compareTo("AutoCompleteTextView") != 0) pDialog.dismiss();
runOnUiThread(new Runnable() {
public void run(){
do something
}
});
}
}
public void afterTextChanged(Editable s){
// TODO Auto-generated method stub
}
public void beforeTextChanged(CharSequence s, int start, int count, int after){
// TODO Auto-generated method stub
}
public void onTextChanged(CharSequence s, int start, int before, int count){
// TODO Auto-generated method stub
}
}
the error says:
how can I fix this error?
Android Solutions
Solution 1 - Android
Try this: getActivity().runOnUiThread(new Runnable...
It's because:
-
the implicit
this
in your call torunOnUiThread
is referring to AsyncTask, not your fragment.
Note that Activity
just executes the Runnable
if you're already on the main thread, otherwise it uses a Handler
. You can implement a Handler
in your fragment if you don't want to worry about the context of this
, it's actually very easy:
// A class instance
private Handler mHandler = new Handler(Looper.getMainLooper());
// anywhere else in your code
mHandler.post(<your runnable>);
// ^ this will always be run on the next run loop on the main thread.
EDIT: @rciovati is right, you are in onPostExecute
, that's already on the main thread.
Solution 2 - Android
Use a Kotlin extension function
fun Fragment?.runOnUiThread(action: () -> Unit) {
this ?: return
if (!isAdded) return // Fragment not attached to an Activity
activity?.runOnUiThread(action)
}
Then, in any Fragment
you can just call runOnUiThread
. This keeps calls consistent across activities and fragments.
runOnUiThread {
// Call your code here
}
> NOTE: If Fragment
is no longer attached to an Activity
, callback will not be called and no exception will be thrown
If you want to access this style from anywhere, you can add a common object and import the method:
object ThreadUtil {
private val handler = Handler(Looper.getMainLooper())
fun runOnUiThread(action: () -> Unit) {
if (Looper.myLooper() != Looper.getMainLooper()) {
handler.post(action)
} else {
action.invoke()
}
}
}
Solution 3 - Android
For Kotlin on fragment just do this
activity?.runOnUiThread(Runnable {
//on main thread
})
Solution 4 - Android
In Xamarin.Android
For Fragment:
this.Activity.RunOnUiThread(() => { yourtextbox.Text="Hello"; });
For Activity:
RunOnUiThread(() => { yourtextbox.Text="Hello"; });
Happy coding :-)
Solution 5 - Android
I used this for getting Date and Time in a fragment.
private Handler mHandler = new Handler(Looper.getMainLooper());
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View root = inflater.inflate(R.layout.fragment_head_screen, container, false);
dateTextView = root.findViewById(R.id.dateView);
hourTv = root.findViewById(R.id.hourView);
Thread thread = new Thread() {
@Override
public void run() {
try {
while (!isInterrupted()) {
Thread.sleep(1000);
mHandler.post(new Runnable() {
@Override
public void run() {
//Calendario para obtener fecha & hora
Date currentTime = Calendar.getInstance().getTime();
SimpleDateFormat date_sdf = new SimpleDateFormat("dd/MM/yyyy");
SimpleDateFormat hour_sdf = new SimpleDateFormat("HH:mm a");
String currentDate = date_sdf.format(currentTime);
String currentHour = hour_sdf.format(currentTime);
dateTextView.setText(currentDate);
hourTv.setText(currentHour);
}
});
}
} catch (InterruptedException e) {
Log.v("InterruptedException", e.getMessage());
}
}
};
}
Solution 6 - Android
You can also post runnable using the view from any other thread. But be sure that the view is not null:
tView.post(new Runnable() {
@Override
public void run() {
tView.setText("Success");
}
});
According to the Documentation:
"boolean post (Runnable action) Causes the Runnable to be added to the message queue. The runnable will be run on the user interface thread."