Question

I am trying to send the events from one Java class to Activity.

Scenario is, Will be having some data in the native, native will call the callback function which is in java code, This class processes data, after the processing i need to update the UI. I want to update the UI at one place in the Activity handler. (Dont want to use runOnUiThread() everywhere).

I was not able to send the events properly with the below approaches.
1st Approach:
1) Define functions for posting messages in to the queue and call these functions.
2) To call the above mentioned functions (point 1) we need context, if i maintain the static variable for maintaining the context and returning it, if the activity is created twice we wont able to get the write context for the first activity.

public class Activity1 {
    protected static Context myContext = null;
    protected Handler myHandler = null;

    @override 
    public void onCreate() {
        myContext = this;
        myHandler = new Handler();
    }

    public static Context getMyContext() {
        return myContext;
    }

    public void postEvent1() {
        myHandler.sendMessage();
    }
}

2nd Approach:
1) Making the handler as a static variable and returning this with the help of static function. – Not a good design to expose the internal variables.
2) Cons will be like above, when a second activity is created.

public class Activity1 {
    protected static Handler myHandler = null;

    @override 
    public void onCreate() {
        myHandler = new Handler();
    }

    public static Context getMyHandler() {
        return myHandler;
    }
}

Is it possible to get the activity context without using the static variables and static functions?

Please share the knowledge if anyone knows. 🙂

Thanks & Regards,
SSuman185

Answer 1

I used a container class HashMap for storing the contexts with the key.

I used the name of the class as the key.

When the second activity is trying to register with class containing hashmap, it will reply with context of the already stored activity (null if not).

So like this I am able to store the contexts’ of the classes and avoid loosing of the first activity context if I am creating the second one.

Please add if any one gets better solution.