CODEWITHSUNDEEP
android
batman
batman

Reputation: 4908

Waiting till the async task finish its work

I'm very new to programming and I have some doubts.

I have a AsyncTask which is I call as RunInBackGround.

and I start this process like:

new RunInBackGround().execute();

But I wish to wait until this call is finish its executing, before proceeding to the other statements of code.

How can I do that?

Are there any way for it?

Upvotes: 94

Views: 220095

Answers (5)

Nearyuk
Nearyuk

Reputation: 178

I think the easiest way is to create an interface to get the data from onpostexecute and run the Ui from interface :

Create an Interface :

public interface AsyncResponse {
    void processFinish(String output);
}

Then in asynctask

@Override
protected void onPostExecute(String data) {
    delegate.processFinish(data);
}

Then in yout main activity

@Override
public void processFinish(String data) {
     // do things

}

Upvotes: 1

ρяσѕρєя K
ρяσѕρєя K

Reputation: 132972

wait until this call is finish its executing

You will need to call AsyncTask.get() method for getting result back and make wait until doInBackground execution is not complete. but this will freeze Main UI thread if you not call get method inside a Thread.

To get result back in UI Thread start AsyncTask as :

String str_result= new RunInBackGround().execute().get();

Upvotes: 140

Stefan de Bruijn
Stefan de Bruijn

Reputation: 6319

Although optimally it would be nice if your code can run parallel, it can be the case you're simply using a thread so you do not block the UI thread, even if your app's usage flow will have to wait for it.

You've got pretty much 2 options here;

  1. You can execute the code you want waiting, in the AsyncTask itself. If it has to do with updating the UI(thread), you can use the onPostExecute method. This gets called automatically when your background work is done.

  2. If you for some reason are forced to do it in the Activity/Fragment/Whatever, you can also just make yourself a custom listener, which you broadcast from your AsyncTask. By using this, you can have a callback method in your Activity/Fragment/Whatever which only gets called when you want it: aka when your AsyncTask is done with whatever you had to wait for.

Upvotes: 38

Zar E Ahmer
Zar E Ahmer

Reputation: 34360

AsyncTask have four methods..

onPreExecute  -- for doing something before calling background task in Async

doInBackground  -- operation/Task to do in Background

onProgressUpdate  -- it is for progress Update

onPostExecute  -- this method calls after asyncTask return from doInBackground.

you can call your work on onPostExecute() it calls after returning from doInBackground()

onPostExecute is what you need to Implement.

Upvotes: 16

KDeogharkar
KDeogharkar

Reputation: 10959

In your AsyncTask add one ProgressDialog like:

private final ProgressDialog dialog = new ProgressDialog(YourActivity.this);

you can setMessage in onPreExecute() method like:

this.dialog.setMessage("Processing..."); 
this.dialog.show();

and in your onPostExecute(Void result) method dismiss your ProgressDialog.

Upvotes: 16

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