How to always run some piece of code in android regardless of which activity or service run first in android?

I would like to run a piece of code every time any activity or service is started. In this piece of code, I might do things such as set the default uncaught exception handler and manage log levels.

The problem is that I have an activity which starts with the user clicking the application icon. I have another which starts if a certain intent is broadcasted, possibly from another app and possibly called bef开发者_StackOverflowore the user click the launch icon. Same goes for services.

I need to guarantee that a certain piece of code will be run while keeping the code clean; that is to say, without having to manually add that snippet of code to every activity and service class that I have.

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Could you not extend the basic Activity class for Android like this:

public class MyClass extends Activity {

    public void onCreate(Bundle bundle) {
        //Add custom code here
    }

}

Then have all of your actual "Activity"'s in your application extend the custom class?

public class MyInterfaceClass extends MyClass {
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        //Other code here
    }
}

That way all your custom code will be called when the Activity starts up.

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For an application called Wibble...

public class Wibble extends Application {
    protected static void DoSomething()
    {
        // Do your common code here
    }
}

Then extend Activity...

public class WibbleActivity extends Activity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Wibble.DoSomething();
    }
}

Then derive all activity classes from WibbleActivity...

public class Whatever extends WibbleActivity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    // WibbleActivity calls Wibble.DoSomething()
    // so the 'Whatever' class doesn't have to.
    }
}

Any Activity derived from WibbleActivity will run Wibble.DoSomething() implicitly.

If you want Services in the mix I can't help - I'm an Android 'rookie' and haven't got on to Services yet but I suspect extending your own app-level Service class might work in the same way.

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You could extend Application and do it in its onCreate() method.

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You have two choices

A) You can manually add the code - it might be only two lines importing and instantiating something from a source file you copy in unmodified - to every separate component that you write. It will only be in your projects, not in other people's unless they do it too.

B) You can, after no small difficulty, learn to make your own custom version of android that automatically does this each time it starts up a suitable component, and install this customized version on developer phones or hacked consumer phones.

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"started" is ambiguous - what are you referring to? onCreate? onResume?

In any case, your best bet is to have a separate class with a static method that does the code you are talking about, and you call that in every single onCreate (or onResume, whichever you need) of each one of your activities.

That, or you create your own Activity subclass and derive all your activites from it, and override onCreate (or onResume). All your onCreate/onResume implementations are required to call the superclass' implementation, so you're guaranteed to have your code caled.