Question

Imagine that I have a camera app where I show a small MapView in one corner showing where is the device located. So I have to extend my activity from a MapActivity to do that.

Then imagine that I want to release my app in a device without Google Apis, like the Kindle, for instance. As the MapActivity does not exist anymore, I should extend from a regular Activity.

I know that I can set

<uses-library
        android:name="com.google.android.maps"
        android:required="false" />

To let the user install the app even if the library is missing. And then use

    try {
        Class.forName("com.google.android.maps.MapView");
        googleMapsEnabled = true;
    } catch( ClassNotFoundException e ) {
        googleMapsEnabled = false;
    }

to check if the MapView class is present or not.

But the problem is the base class that I extend from, it should be Activity instead of MapActivity if Google Maps are not available.

My question is, how can I use the same code to support both options, without duplicating the whole code into different classes depending on the installed libs?

Answer 1

For what it’s worth, my usual approach with things like this (ie: where I have to inherit from two different base classes in different scenarios, but ultimately want the same – or nearly the same – behavior) is to break out as much as I can of the common functionality into a static helper class that I call from both classes.