Question

I have one activity A, that has one button and one list view which shows names of books . on click of the button, activity B starts, there user fill the book form and save it . when he press back button , user comes to activity A. Here the book name should be updated in listview. I think I have to write some code in onResume() . Can u please tell me what to write. I am using customised list view.

Answer 1

Start activity B with startActivityForResult() and use method onActivityResult() to restart or process the new data

For example, to start Activity B:

String callingActivity = context.getLocalClassName();
Intent newActivity = new Intent(getApplicationContext(),ActivityB.class);
newActivity.setData(Uri.parse(callingActivity));
startActivityForResult(newActivity, 0);

Then somewhere in your Activity A class:

protected void onActivityResult(int requestCode, int resultCode, Intent data){
        if(requestCode == 0){
            // do processing here
        }
    }

The other answers should suffice, but onResume() can be called in cases where the activity is resumed by other means.

To simply restart Activity A when user presses back button from Activity B, then put the following inside the onActivityResult:

if(requestCode == 0){
            finish();
            startActivity(starterintent);

        }

And in the onCreate of Activity A, add starterintent = getIntent();

Just remember to initiate the variable with Intent starterintent; somewhere before your onCreate is called.

e.g.

public class ActivityA extends ListActivity {
  Intent starterintent;

  public void onCreate(Bundle b){
    starterintent = getIntent();
  }

  protected void onActivityResult(int requestCode, int resultCode, Intent data){
    if(requestCode == 0){
      finish();
      startActivity(starterintent);
    }
  }

  private void startActivityB(){
    String callingActivity = context.getLocalClassName();
    Intent newActivity = new Intent(getApplicationContext(),ActivityB.class);
    newActivity.setData(Uri.parse(callingActivity));
    startActivityForResult(newActivity, 0);
  }

}

Then just call startActivityB() from a button click or whatever