Android "Best Practice" returning values from a dialog

Question

What is the "correct" way to return the values to the calling activity from a complex custom dialog - say, text fields, date or time picker, a bunch of radio buttons, etc, plus a "Save" and "Cancel" button?

Some of the techniques I've seen on the web include:

• public data members in the Dialog-derived class which can be read by the Activity

• public "get" accessors . . . " . . " . . "

• Launching the dialog with an Intent (as opposed to show() ) plus handlers in the Dialog class which take input from the various controls and bundle them up to be passed back to the Activity so when listener hits "Save" the bundle is passed back using ReturnIntent()

• Listeners in the Activity which process input from the controls that are in the dialog e.g., so the TimePicker or DatePicker's listeners are really in the Activity. In this scheme practically all the work is done in the Activity

• One Listener in the Activity for the "Save" button and then the Activity directly interrogates the controls in the dialog; the Activity dismisses the dialog.

...plus more that I've already forgotten.

Is there a particular technique that's considered the canonically correct or "best practice" method?

Answer 1

Perhaps I'm mis-understanding your question, but why not just use the built in listener system:

builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {     public void onClick(DialogInterface dialog, int id) {         // run whatever code you want to run here         // if you need to pass data back, just call a function in your         // activity and pass it some parameters     } }) 

This is how I've always handled data from dialog boxes.

EDIT: Let me give you a more concrete example which will better answer your question. I'm going to steal some sample code from this page, which you should read:

http://developer.android.com/guide/topics/ui/dialogs.html

// Alert Dialog code (mostly copied from the Android docs AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("Pick a color"); builder.setItems(items, new DialogInterface.OnClickListener() {     public void onClick(DialogInterface dialog, int item) {         myFunction(item);     } }); AlertDialog alert = builder.create(); 

...

// Now elsewhere in your Activity class, you would have this function private void myFunction(int result){     // Now the data has been "returned" (as pointed out, that's not     // the right terminology) }