Android return data to previous activity

Question

I need you help: I want to putExtra data to the previous activity before finishing the current activity.

Eg: Activity A start Activity B When I finish Activity B I want in Activity A new data.

How I can do that? Many thanks before

Answer 1

Android SDK explanation here, better SO question answer+example here.

Answer 2

Use startActivityforResult to open the activity B..then override onActivityResult(int, int, Intent) in your activity A..

Example:

public class MyActivity extends Activity {
 ...

 static final int PICK_CONTACT_REQUEST = 0;

 protected boolean onKeyDown(int keyCode, KeyEvent event) {
     if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
         // When the user center presses, let them pick a contact.
         startActivityForResult(
             new Intent(Intent.ACTION_PICK,
             new Uri("content://contacts")),
             PICK_CONTACT_REQUEST);
        return true;
     }
     return false;
 }

 protected void onActivityResult(int requestCode, int resultCode,
         Intent data) {
     if (requestCode == PICK_CONTACT_REQUEST) {
         if (resultCode == RESULT_OK) {
             // A contact was picked.  Here we will just display it
             // to the user.
             startActivity(new Intent(Intent.ACTION_VIEW, data));
         }
     }
 }
}

check http://developer.android.com/reference/android/app/Activity.html