Change DialogFragment enter/exit transition at just before dismissing

You can do it inside your DialogFragment, without changing

getDialog().getWindow()
            .getAttributes().windowAnimations

You should animate “decor view” in onStart and onClick.

This is the code snipped :

Create Dialog first

@Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        return new AlertDialog.Builder(getActivity())
                .setTitle("Hello from animated dialog :)")
                .setNegativeButton("Cancel",
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int whichButton) {
                                //we have to add button here and then override it's click in onStart
                            }
                        }
                )
                .setCancelable(false)
                .create();
    }

Then override onStart method

@Override
    public void onStart() {
        super.onStart();

        AlertDialog dialog = (AlertDialog)getDialog();

        final View decorView = getDialog()
                .getWindow()
                .getDecorView();

        ObjectAnimator scaleDown = ObjectAnimator.ofPropertyValuesHolder(decorView,
                PropertyValuesHolder.ofFloat("scaleX", 0.0f, 1.0f),
                PropertyValuesHolder.ofFloat("scaleY", 0.0f, 1.0f),
                PropertyValuesHolder.ofFloat("alpha", 0.0f, 1.0f));
        scaleDown.setDuration(2000);
        scaleDown.start();


        Button positiveButton = dialog.getButton(Dialog.BUTTON_NEGATIVE);
        positiveButton.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                final View decorView = getDialog()
                        .getWindow()
                        .getDecorView();

                ObjectAnimator scaleDown = ObjectAnimator.ofPropertyValuesHolder(decorView,
                        PropertyValuesHolder.ofFloat("scaleX", 1.0f, 0.0f),
                        PropertyValuesHolder.ofFloat("scaleY", 1.0f, 0.0f),
                        PropertyValuesHolder.ofFloat("alpha", 1.0f, 0.0f));
                scaleDown.addListener(new Animator.AnimatorListener() {
                    @Override
                    public void onAnimationEnd(Animator animation) {
                        dismiss();
                    }

                    @Override
                    public void onAnimationStart(Animator animation) {
                    }
                    @Override
                    public void onAnimationCancel(Animator animation) {
                    }
                    @Override
                    public void onAnimationRepeat(Animator animation) {
                    }
                });
                scaleDown.setDuration(2000);
                scaleDown.start();
            }
        });
    }

Here is the result animation

And if you remove scale properties from my code you will get only alpha animation. Exactly as you wanted.

Remove this:

PropertyValuesHolder.ofFloat("scaleX", 1.0f, 0.0f),
PropertyValuesHolder.ofFloat("scaleY", 1.0f, 0.0f),