Using AsyncTask to start activity

Question

I am using asyncTask to show Dialog and then after few minutes then launch a new activity.

unfortunately that activity start before task finished ???

package com.android.grad;

import android.app.Activity;

import android.app.ProgressDialog;

import android.os.AsyncTask;

import android.widget.Toast;

public class LoginTask extends AsyncTask<Void, Void, Boolean> {
private Activity activity;
private ProgressDialog pd;

public LoginTask(Activity activity) {
    this.activity = activity;
}

@Override
protected void onPreExecute() {
    pd = ProgressDialog.show(activity, "Signing in",
            "Please wait while we are signing you in..");
}

@Override
protected Boolean doInBackground(Void... arg0) {
    try {
        Thread.sleep(10000000);
    } catch (InterruptedException e) {
    }
    pd.dismiss();
    return true;
}

@Override
protected void onPostExecute(Boolean result) {
    Toast.makeText(activity, Boolean.toString(result), Toast.LENGTH_LONG).show();
}

}

and i execute the task from button click listener :S

private OnClickListener loginOnClick = new OnClickListener() {

        public void onClick(View v) {
            new LoginTask(LoginActivity.this).execute();
            startActivity(new Intent(LoginActivity.this, BuiltInCamera.class));
        }
    };

Is there way to startActivity from my subClass ofAsyncTask .

yes, you should start it in your onPostExecute method, right after you show your Toast — Tomislav Novoselec, May 24 '12 at 11:59

score 34 · Accepted Answer · answered May 24 '12 at 12:00

34

Yes, you can start activity from AsyncTask's sub class. See below:

@Override
protected void onPostExecute(Boolean result) {
    Toast.makeText(activity, Boolean.toString(result), Toast.LENGTH_LONG).show();

    activity.startActivity(new Intent(activity, BuiltInCamera.class));
}

After making this change, make sure you do remove startActivity from OnClickListener

answered May 24 '12 at 12:00

waqaslam

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What does the activity come? (new Intent(activity, ...) – Mathieu Dec 26 '12 at 16:31
1

`activity` is the reference to your Activity i.e. received through the AsyncTask's constructor. – waqaslam Dec 26 '12 at 16:51
And if the activity is destroyed? – Brais Gabin Jun 13 '13 at 11:55
then it will crash. for safe side make a check if `activity != null` before using its reference – waqaslam Jun 13 '13 at 11:58

score 5 · Answer 2 · edited Aug 13 '15 at 12:16

5

Call startActivity inside onPostExecute method of AsyncTask

edited Aug 13 '15 at 12:16

Iharob Al Asimi

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answered May 24 '12 at 11:59

Raghu Nagaraju

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the method is not found :S i try it more and more – Mahmoud Emam May 24 '12 at 12:00
1

u should use YourClassActivityName.this.startActivity. Then it will work – Raghu Nagaraju May 24 '12 at 13:41

score 5 · Answer 3 · edited May 24 '12 at 12:18

5

Call this startActivity(new Intent(LoginActivity.this, BuiltInCamera.class)); from onPostExecute() after Displaying toast message.

In this way, new activity will be called after your AsyncTask is over.

edited May 24 '12 at 12:18

Verbeia

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answered May 24 '12 at 12:00

Shrikant Ballal

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score 5 · Answer 4 · answered Mar 27 '15 at 07:18

5

You can also use

    Intent intent = new Intent(activity, PageViewActivity.class);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
    activity.getApplicationContext().startActivity(intent);

answered Mar 27 '15 at 07:18

Atish Dabholkar

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2

it works fine but in my try the activity run for tow time - one in new activity ( first line - and second in third line – ehsan wwe Oct 05 '17 at 07:06

Using AsyncTask to start activity

4 Answers4

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