updating array adapter onActivityResult after getting data from dialogfragment - android-fragments

Question

My dilema is that i am coming from a dialogfragment to my weighInFragment with two pieces of information: a date and an int. I want to be able to use these two pieces of information and construct a newEntry which needs to be added to an existing Arrayadapter. The arraylist is displayed on the weighInFragment and i use the dialogfragment to capture information for new entries. However, when i try to add the new entry to the adapter i get a nullpointer exception which i believe is due to the adapter being null. So i am wondering how could i get this adapter and be able to add the new entry?
Here is y onActivityResult which is where i land after i hit "save" on my dialog:
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(requestCode) {
case DATEPICKER_FRAGMENT:
if (resultCode == Activity.RESULT_OK) {
Bundle bundle=data.getExtras();
Date date = (Date) bundle.getSerializable("date");
int weight = (Integer) bundle.getSerializable("weight");
Log.d("NewEntry", "Date is: " + date + "Weight: " +weight );
WeighInAdapter adapter = (WeighInAdapter)getListAdapter();
WeighInEntry newEntry = new WeighInEntry();
newEntry.setDate(date);
newEntry.setWeight(weight);
adapter.add(newEntry);
adapter.notifyDataSetChanged();
} else if (resultCode == Activity.RESULT_CANCELED){
}
break;
}
}
This is where i get my data in the dialogadapter:
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
// LayoutInflater inflater = getActivity().getLayoutInflater();
final View v = getActivity().getLayoutInflater()
.inflate(R.layout.weigh_in_dialog, null);
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(v)
// Add action buttons
.setPositiveButton(R.string.save, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
DatePicker datePicker = (DatePicker)v.findViewById(R.id.datePicker1);
EditText weightAmount = (EditText) v.findViewById(R.id.weight);
mDate = getDateFromDatePicket(datePicker);
mWeight = Integer.parseInt(weightAmount.getText().toString());
Intent i = new Intent();
Bundle extras=new Bundle();
extras.putSerializable("date", mDate); //putString("date",Month);
extras.putInt("weight",mWeight);
i.putExtras(extras);
getTargetFragment().onActivityResult(getTargetRequestCode(),Activity.RESULT_OK,i);
dismiss() ;
}
})
.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
NewEntryDialogFragment.this.getDialog().cancel();
Log.d("CANCEL WAS PRESSED:", "!!!!!!!!!!!!");
}
});
return builder.create();
}
This is the logcat error:
11-17 17:42:51.050: D/NewEntry(2593): Date is: Tue Nov 17 17:42:51 EST 2015Weight: 200
11-17 17:42:51.060: D/AndroidRuntime(2593): Shutting down VM
11-17 17:42:51.060: W/dalvikvm(2593): threadid=1: thread exiting with uncaught exception (group=0xb1ae9b90)
11-17 17:42:51.070: E/AndroidRuntime(2593): FATAL EXCEPTION: main
11-17 17:42:51.070: E/AndroidRuntime(2593): Process: edu.bu.juanl.finalproject, PID: 2593
11-17 17:42:51.070: E/AndroidRuntime(2593): java.lang.NullPointerException
11-17 17:42:51.070: E/AndroidRuntime(2593): at edu.bu.juanl.finalproject.WeighInFragment.onActivityResult(WeighInFragment.java:141)
11-17 17:42:51.070: E/AndroidRuntime(2593): at edu.bu.juanl.finalproject.NewEntryDialogFragment$1.onClick(NewEntryDialogFragment.java:84)
11-17 17:42:51.070: E/AndroidRuntime(2593): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
11-17 17:42:51.070: E/AndroidRuntime(2593): at android.os.Handler.dispatchMessage(Handler.java:102)
11-17 17:42:51.070: E/AndroidRuntime(2593): at android.os.Looper.loop(Looper.java:137)
11-17 17:42:51.070: E/AndroidRuntime(2593): at android.app.ActivityThread.main(ActivityThread.java:4998)
11-17 17:42:51.070: E/AndroidRuntime(2593): at java.lang.reflect.Method.invokeNative(Native Method)
11-17 17:42:51.070: E/AndroidRuntime(2593): at java.lang.reflect.Method.invoke(Method.java:515)
11-17 17:42:51.070: E/AndroidRuntime(2593): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
11-17 17:42:51.070: E/AndroidRuntime(2593): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
11-17 17:42:51.070: E/AndroidRuntime(2593): at dalvik.system.NativeStart.main(Native Method)
11-17 17:42:53.440: I/Process(2593): Sending signal. PID: 2593 SIG: 9
ive tried multiple things and i cant figure it out!

Answer 1

The DialogPickerFragment inputs data from the user and this needs to be reflected in a different dialog fragment that contains a listview.
The data is being passed to the parent activity and it is trying to access an element belonging to the listview fragment. Herein lies the problem. The activity will not have access to the fragments list adapter.
What you should instead do is implement an interface between the activity and the listview fragment and pass in the data.Check out the android developer guide: http://developer.android.com/training/basics/fragments/communicating.html