I have an Activity, and in that I have a class.
text=new Dynamictext(...);
text.setText("txt");
in my DynamicText java I have this code:
public void setText(String text) {
this.text=text;
new asyncCreateText().execute();
//this.createText(text);
}
//private Handler handler = new Handler();
private class asyncCreateText extends AsyncTask<Void, Void, Void>
{
@Override
protected Void doInBackground(Void... unused) {
return null;
}
@Override
protected void onPostExecute(Void unused) {
}
}
I get:
ERROR/AndroidRuntime(5176): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
How can I handle this error?
ERROR/AndroidRuntime(5370): java.lang.ExceptionInInitializerError
ERROR/AndroidRuntime(5370): at com.l.start.DynamicText.setText(DynamicText.java:125)
ERROR/AndroidRuntime(5370): at com.l.start.OpenGLRenderer.initfonts(OpenGLRenderer.java:168)
ERROR/AndroidRuntime(5370): at com.l.start.OpenGLRenderer.init(OpenGLRenderer.java:119)
ERROR/AndroidRuntime(5370): at com.l.start.OpenGLRenderer.onSurfaceChanged(OpenGLRenderer.java:90)
ERROR/AndroidRuntime(5370): at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1120)
ERROR/AndroidRuntime(5370): at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:975)
ERROR/AndroidRuntime(5370): Caused by: java.lang.RuntimeException:
Can't create handler inside thread that has not called Looper.prepare()
ERROR/AndroidRuntime(5370): at android.os.Handler.<init>(Handler.java:121)
ERROR/AndroidRuntime(5370): at android.os.AsyncTask$InternalHandler.<init>(AsyncTask.java:421)
ERROR/AndroidRuntime(5370): at android.os.AsyncTask$InternalHandler.<init>(AsyncTask.java:421)
ERROR/AndroidRuntime(5370): at android.os.AsyncTask.<clinit>(AsyncTask.java:152)
ERROR/AndroidRuntime(5370): ... 6 more
This question is related to
android
runtimeexception
You create handler in background thread this way
private void createHandler() {
Thread thread = new Thread() {
public void run() {
Looper.prepare();
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
// Do Work
handler.removeCallbacks(this);
Looper.myLooper().quit();
}
}, 2000);
Looper.loop();
}
};
thread.start();
}
Try running you asyntask from the UI thread. I faced this issue when I wasn't doing the same!
Activity.runOnUiThread()
does not work for me. I worked around this issue by creating a regular thread this way:
public class PullTasksThread extends Thread {
public void run () {
Log.d(Prefs.TAG, "Thread run...");
}
}
and calling it from the GL update this way:
new PullTasksThread().start();
All the answers above are correct, but I think this is the easiest example possible:
public class ExampleActivity extends Activity {
private Handler handler;
private ProgressBar progress;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
progress = (ProgressBar) findViewById(R.id.progressBar1);
handler = new Handler();
}
public void clickAButton(View view) {
// Do something that takes a while
Runnable runnable = new Runnable() {
@Override
public void run() {
handler.post(new Runnable() { // This thread runs in the UI
@Override
public void run() {
progress.setProgress("anything"); // Update the UI
}
});
}
};
new Thread(runnable).start();
}
}
What this does is update a progress bar in the UI thread from a completely different thread passed through the post() method of the handler declared in the activity.
Hope it helps!
Try this
Handler mHandler = new Handler(Looper.getMainLooper());
mHandler.post(new Runnable() {
@Override
public void run() {
//your code here that talks with the UI level widgets/ try to access the UI
//elements from this block because this piece of snippet will run in the UI/MainThread.
}
});
Source: Stackoverflow.com