Handle .canGoBack() from multiple fragments

Question

I have an activity with several fragments containing web views. I have exposed the web views canGoBack and goBack to the MainActivity of the application.

At the moment I have it working for one fragment, but I am not sure how to check which fragment is sending the information, and in turn how to send the appropriate fragment the response.

Here is the code involved from the MainActivity:

@Override
public void onBackPressed() {

    circleFragment.canGoBack();
    if (circleFragment.canGoBack()) {
        circleFragment.goBack();

    } else {
        super.onBackPressed();
    }
}

Answer 1

Instead of implementing a boolean canGoBack()

Just create an interface "Backable"

public interface Backable {
    public void goBack();
    public boolean canGoBack();
}

Make your Fragment implement Backable and use if(myFragment instanceof Backable) to now if your current Fragment is backable

So:

@Override
public void onBackPressed() {

    if(myFragment instanceof Backable) {
        ((Backable) myFragment).canGoBack();
        if(((Backable) myFragment).canGoBack()){
            ((Backable) myFragment).goBack();

        }else{
            super.onBackPressed();
        }
    }else{
        super.onBackPressed();
    }

}