Getting java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

Question

I am trying to call AsyncTask from runonUiThread like below

MutiThreadActivity.this.runOnUiThread(new Runnable() {
    public void run() {
        Toast.makeText(MutiThreadActivity.this, "This is Toast!!!", Toast.LENGTH_SHORT).show();
        new backgroundTask(mcon).execute();
    }
});

But doInBackground is not invoked during java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()"

Any one suggest me where am doing wrong.How can i call Asyntask from RunonUithread method in android?

Thanks in advance.

`new backgroundTask(mcon).execute();` here is the problem... may be you are calling tost or any Ui element in doInBackground of `backgroundTask` async task..Can you show the code of `backgroundTask` AsyncTask class. — SRB Bans, Nov 10 '15 at 06:55

score 1 · Answer 1 · answered Nov 10 '15 at 04:59

1

Don't use asycnc task instead use handler or timer it give you illusion of seprate thread by posting in message queue after some delay read about handler it is simple apporch

answered Nov 10 '15 at 04:59

Nikhil Kamboj

33
1
6

Thanks for you quick response.Can you please provide me any code regarding this answer – Pinki Nov 10 '15 at 05:07
Handler handler = new Handler(); handler.postDelay(new Runnable() { public void run() { Toast.makeText(MutiThreadActivity.this, "This is Toast!!!", Toast.LENGTH_SHORT).show(); } },1000); – Nikhil Kamboj Nov 10 '15 at 05:13
when I am added server communi cation code inside handler am getting "android.os.NetworkOnMainThreadException"" – Pinki Nov 10 '15 at 05:18
this is kind of hint serch for detail to make this your base – Nikhil Kamboj Nov 10 '15 at 05:19
Async task Class internally use the handler and thread.And its doInBackGround method runs as a worker thread. And OnPreExecute and onPostExecute runs on ui thread. – SRB Bans Nov 10 '15 at 07:00
greate you got your ans now – Nikhil Kamboj Nov 10 '15 at 07:13
it seems the error in `new backgroundTask(mcon).execute();` call – SRB Bans Nov 10 '15 at 07:30

Getting java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

1 Answers1