Looking for best way to implement modal dialog in onPause

Question

I have fragment with EditTexts that user can change.

As well I have back button on Toolbar (and physical back button too)

When the user hits back, I check if the data was changed and if it was - I need to open dialog and ask the user "Do you want to save changes?". Get the click and act accordingly (positive or negative answer).

The best place to save the data (maybe I wrong) is in onPause of this fragment.

The problem is with the dialog - it is not modal and while it's showing the question and waits for user reaction - the fragment under it disappears and previous come back from stack. I need to "pause the onPause" with the dialog until the user make his choice. What the easy (or most correct) way to do it?

@Override
public void onPause() {
    if (!(text.getText().toString().equals(user.getName())))
    {
        new MaterialDialog.Builder(getActivity())
                .title("Save changes?")
                .content("You changed you personal details, save changes?")
                .cancelable(false)
                .positiveText("Save")
                .negativeText("Discard")
                .onPositive(new MaterialDialog.SingleButtonCallback() {
                    @Override
                    public void onClick(@NonNull MaterialDialog dialog, @NonNull DialogAction which) {
                        save();
                    }})
                .show();
    }
    super.onPause();
}

If I want to do it before onPause - I'll need to catch the Toolbar's back button and physical back button - seems too much work for this. Looking for elegant way.

Thank you

Answer 1

onPause is called when the activity moves into the background (not being shown on the screen anymore).

To show a dialog before the app goes off screen, you can override the "onBackPressed" function in an activity.

@Override
public void onBackPressed() {
    performBackPressed();
}

public void performBackPressed(){
    //show your dialog here 
    //call finish(); when done to close app
}

You can call the performBackPressed() method whenever the Toolbar's back button is pressed too.

If you're trying to show a popup from a fragment when back is pressed, then you still have to override that method in the activity, then notifiy the fragment whenever back is pressed.

In my app I have a container in the activity that holds all my fragments. I use this code to get the currently active fragment:

YourFragmentClass curFrag = (YourFragmentClass) fragmentManager.findFragmentById(R.id.fragment_container);

then I have a method in the fragment called onBackPressed() and I just call that on the fragment I just got.