Sending arrayList of objects back on press of back button

Question

Im having some problems when sending an arrayList of objects to another activity on press of the back button. The weird thing is that i can send this arrayList from the first activity to the second and use it. But when I try to send it back (back button), the app crashes. This is how I do it:

Sending the arrayList (and a string) from activity 1:

Intent intent = new Intent(v.getContext(), ShowDay.class);
        intent.putExtra("exerciseList", list);
        intent.putExtra("day", selectedFromList);
        startActivityForResult(intent, EDIT_TRAININGDAY_RESPONSE);

And receiving this in the second activity:

Intent intent = getIntent();
        exercises = (ArrayList<Exercise>) intent.getSerializableExtra("exerciseList");
        day = intent.getStringExtra("day");

In this activity I'm doing the following to send it back:

 @Override
      public void onBackPressed(){        
            Intent intent = new Intent();
            intent.putExtra("exerciseList",exercises);
            intent.putExtra("day", day);
            setResult(RESULT_OK, intent);
            finish();
       }

And to receive the above (back in activity 1) I'm doing this:

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         if (requestCode == EDIT_TRAININGDAY_RESPONSE) {
             if (resultCode == RESULT_OK) {

                Intent intent = getIntent();
                ArrayList<Exercise> newExerciseList = (ArrayList<Exercise>) intent.getSerializableExtra("exerciseList");
                String currentDay = intent.getStringExtra("day");
                     // Other code ...
                }
       }
}

It is when I tab the back button the app crashes and I really can't see what's wrong. So I really hope anyone figure this out.

Here is my log output (after the crash) if you need it:

12-26 18:10:56.151: E/AndroidRuntime(18849): FATAL EXCEPTION: main
12-26 18:10:56.151: E/AndroidRuntime(18849): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { (has extras) }} to activity {com.pack.androidexam/com.pack.androidexam.ShowPickedProgram}: java.lang.NullPointerException
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.ActivityThread.deliverResults(ActivityThread.java:3141)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.ActivityThread.handleSendResult(ActivityThread.java:3184)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.ActivityThread.access$1100(ActivityThread.java:130)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1243)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.os.Handler.dispatchMessage(Handler.java:99)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.os.Looper.loop(Looper.java:137)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.ActivityThread.main(ActivityThread.java:4745)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at java.lang.reflect.Method.invokeNative(Native Method)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at java.lang.reflect.Method.invoke(Method.java:511)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at dalvik.system.NativeStart.main(Native Method)
12-26 18:10:56.151: E/AndroidRuntime(18849): Caused by: java.lang.NullPointerException
12-26 18:10:56.151: E/AndroidRuntime(18849):    at com.pack.androidexam.ShowPickedProgram.onActivityResult(ShowPickedProgram.java:98)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.Activity.dispatchActivityResult(Activity.java:5192)
12-26 18:10:56.151: E/AndroidRuntime(18849):    at android.app.ActivityThread.deliverResults(ActivityThread.java:3137)
12-26 18:10:56.151: E/AndroidRuntime(18849):    ... 11 more

Answer 1

use it. removed the line getIntent and used data which you receive in the onActivityResult callback.

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
     if (requestCode == EDIT_TRAININGDAY_RESPONSE) {
         if (resultCode == RESULT_OK) {

            //Intent intent = getIntent();
            ArrayList<Exercise> newExerciseList = (ArrayList<Exercise>) data.getSerializableExtra("exerciseList");
            String currentDay = intent.getStringExtra("day");
                 // Other code ...
            }
   }
}