Update activity from another activity [duplicate]

Question

In my activity, I'm calling a second activity from the main activity by startActivityForResult. In my second activity, there are some methods that finish this activity (maybe without a result), however, just one of them returns a result.

For example, from the main activity, I call a second one. In this activity, I'm checking some features of a handset, such as does it have a camera. If it doesn't have then I'll close this activity. Also, during the preparation of MediaRecorder or MediaPlayer if a problem happens then I'll close this activity.

If its device has a camera and recording is done completely, then after recording a video if a user clicks on the done button then I'll send the result (address of the recorded video) back to the main activity.

How do I check the result from the main activity?

Answer 1

From your FirstActivity, call the SecondActivity using the startActivityForResult() method.

For example:

int LAUNCH_SECOND_ACTIVITY = 1
Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, LAUNCH_SECOND_ACTIVITY);

In your SecondActivity, set the data which you want to return back to FirstActivity. If you don't want to return back, don't set any.

For example: In SecondActivity if you want to send back data:

Intent returnIntent = new Intent();
returnIntent.putExtra("result",result);
setResult(Activity.RESULT_OK,returnIntent);
finish();

If you don't want to return data:

Intent returnIntent = new Intent();
setResult(Activity.RESULT_CANCELED, returnIntent);
finish();

Now in your FirstActivity class, write the following code for the onActivityResult() method.

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == LAUNCH_SECOND_ACTIVITY) {
        if(resultCode == Activity.RESULT_OK){
            String result=data.getStringExtra("result");
        }
        if (resultCode == Activity.RESULT_CANCELED) {
            // Write your code if there's no result
        }
    }
} //onActivityResult

To implement passing data between two activities in a much better way in Kotlin, please go through 'A better way to pass data between Activities'.

Answer 2

How to check the result from the main activity?

You need to override Activity.onActivityResult() and then check its parameters:

• requestCode identifies which app returned these results. This is defined by you when you call startActivityForResult().
• resultCode informs you whether this app succeeded, failed, or something different
• data holds any information returned by this app. This may be null.