Question

I have been receiving a large number of bug reports from users reported from force close dialogs that state something like the following:

java.lang.ExceptionInInitializerError
at com.MyRequest.execute(MyRequest.java:59)
at org.nsdev.MySyncAdapter.onPerformSync(MySyncAdapter.java:90)
at android.content.AbstractThreadedSyncAdapter$SyncThread.run(AbstractThreadedSyncAdapter.java:164)
  Caused by: java.lang.RuntimeException: 
  Can't create handler inside thread that has not called Looper.prepare()
at android.os.Handler.<init>(Handler.java:121)
at android.os.AsyncTask$InternalHandler.<init>(AsyncTask.java:421)
at android.os.AsyncTask$InternalHandler.<init>(AsyncTask.java:421)
at android.os.AsyncTask.<clinit>(AsyncTask.java:152)

Now, I’ve been trying to figure out how I should best resolve this issue. Inside my onPerformSync implementation I am creating a number of AsyncTasks and executing them. I suspect my problem is that I’m not waiting for these tasks to complete before returning from onPerformSync. I tried to do the following:

Looper.prepare();

// Execute async tasks

Looper.loop();

And then I set up a counter and when that counter decrements to zero, call Looper.myLooper().quit() inside the callback from the async tasks.

But doing this causes my application to crash even harder with the following runtime error:

java.lang.RuntimeException: Main thread not allowed to quit
    at android.os.MessageQueue.enqueueMessage(MessageQueue.java:175)
    at android.os.Looper.quit(Looper.java:173)
    at org.nsdev.MySyncAdapter$1.requestFinished(MySyncAdapter.java:89)
    at com.MyAsyncTask.onPostExecute(MyAsyncTask.java:84)
    at android.os.AsyncTask.finish(AsyncTask.java:417)
    at android.os.AsyncTask.access$300(AsyncTask.java:127)
    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:4627)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:521)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    at dalvik.system.NativeStart.main(Native Method)

Any idea how to correctly accomplish my sync?

Answer 1

I know this post is old, but for others who come across this thread, what about just not calling looper.quit() on the main thread? The following works for me from a SyncAdpater Service spawning several AsyncTasks, although there may be other reasons not to do this in terms of performance…

Handler h = new Handler(Looper.getMainLooper());
            h.post(new Runnable() {
                public void run() {

                    // AsyncTask... execute();
                }
            });