Simplest yes/no dialog fragment

Question

I\'d like to make a dialog fragment that asks \"Are you sure?\" with a \"yes/no\" reply.

I\'ve looked at the documentation and it\'s really verbose, go

Answer 1

because of Activity / Fragment lifecycle @athor & @lugsprog approach can fail, more elegant way is to **get activity context from method onAttach and store it as weak reference ** (&try to avoid non default constructor in DialogFragment!, to pass any argument to dialog use arguments) like this:

public class NotReadyDialogFragment extends DialogFragment {

    public static String DIALOG_ARGUMENTS = "not_ready_dialog_fragment_arguments";

    private WeakReference<Context> _contextRef;

    public NotReadyDialogFragment() {
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        /** example pulling of arguments */
        Bundle bundle = getArguments();
        if (bundle!=null) {
            bundle.get(DIALOG_ARGUMENTS);
        }

        //
        // Caution !!!
        // check we can use contex - by call to isAttached 
        // or by checking stored weak reference value itself is not null 
        // or stored in context -> example allowCreateDialog() 
        // - then for example you could throw illegal state exception or return null 
        //
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(_contextRef.get());
        alertDialogBuilder.setMessage("...");
        alertDialogBuilder.setNegativeButton("Przerwij", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        return alertDialogBuilder.create();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        _contextRef = new WeakReference<Context>(activity);
    }

     boolean allowCreateDialog() {
         return _contextRef !== null 
                && _contextRef.get() != null;
     }

EDIT: & if You wanna dismiss dialog then:

1. try to get it
2. check if it's exist
3. check if it's showing
4. dismiss

something like this :

        NotReadyDialogFragment dialog = ((NotReadyDialogFragment) getActivity().getFragmentManager().findFragmentByTag("MyDialogTag"));
    if (dialog != null) {
        Dialog df = dialog.getDialog();
        if (df != null && df.isShowing()) {
            df.dismiss();
        }
    }

EDIT2: & if u wanna set dialog as non cancelable u should change onCreatweDialog return statement like this:

    /** convert builder to dialog */
    AlertDialog alert = alertDialogBuilder.create();
    /** disable cancel outside touch */
    alert.setCanceledOnTouchOutside(false);
    /** disable cancel on press back button */
    setCancelable(false);

    return alert;

Answer 2

A DialogFragment is really just a fragment that wraps a dialog. You can put any kind of dialog in there by creating and returning the dialog in the onCreateDialog() method of the DialogFragment.

Heres an example DialogFragment:

class MyDialogFragment extends DialogFragment{
    Context mContext;
    public MyDialogFragment() {
        mContext = getActivity();
    }
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(mContext);
        alertDialogBuilder.setTitle("Really?");
        alertDialogBuilder.setMessage("Are you sure?");
        //null should be your on click listener
        alertDialogBuilder.setPositiveButton("OK", null);
        alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });


        return alertDialogBuilder.create();
    }
}

To create the dialog call:

new MyDialogFragment().show(getFragmentManager(), "MyDialog");

And to dismiss the dialog from somewhere:

((MyDialogFragment)getFragmentManager().findFragmentByTag("MyDialog")).getDialog().dismiss();

All of that code will work perfectly with the support library, by just changing the imports to use the support library classes.

Answer 3

So, what's the simplest way to create and display a really basic Alert Dialog? Bonus points if it's using the support library.

Simply create a DialogFragment(SDK or support library) and override its onCreateDialog method to return an AlertDialog with the desired text and buttons set on it:

public static class SimpleDialog extends DialogFragment {

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        return new AlertDialog.Builder(getActivity())
                .setMessage("Are you sure?")
                .setPositiveButton("Ok", null)
                .setNegativeButton("No way", null)
                .create();
    }

}

To do something when the user uses one of the buttons you'll have to provide an instance of a DialogInterface.OnClickListener instead of the null references from my code.

Answer 4

For those coding with Kotlin and Anko, you can now do dialogs in 4 lines of code:

alert("Order", "Do you want to order this item?") {
    positiveButton("Yes") { processAnOrder() }
    negativeButton("No") { }
}.show()