How to reference the current or main activity from another class

Question

I often find myself needing to access methods that require referencing some activity. For example, to use getWindowManager, I need to access some Activity. But ofte

Answer 1

I think this is the solution to this, you get your context static and then reference it statically.

Answer 2

You can implement the necessary methods in your activity and implement a Handler. Then, simply pass a handler instance to your classes, where you can obtain a message for handler and send it to target.

Answer 3

Handle the Intent in the class you want to do these methods, and send your information to it in a Bundle like so:

    Intent i = new Intent("android.intent.action.MAIN");
    i.setComponent(new ComponentName("com.my.pkg","com.my.pkg.myActivity"));
    Bundle data = new Bundle();

    i.putExtras(data);

    startActivityForResult(i);

Then use an OnActivityResultListener to grab the new data.

Answer 4

I found a way to get the Activity to a non-activity class that I have not seen discussed in forums. This was after numerous failed attempts at using getApplicationContext() and of passing the context in as a parameter to constructors, none of which gave Activity. I saw that my adapters were casting the incoming context to Activity so I made the same cast to my non-activity class constructors:

public class HandleDropdown extends Application{
...
    public Activity activity;
...
public HandleDropdown() {
    super();
}
public HandleDropdown(Activity context) {
    this.activity = context;
    this.context = context;
}
public void DropList(View v,Activity context) {
    this.activity = context;
    this.context = context; 
...
}

After doing this cast conversion of Context to Activity I could use this.activity wherever I needed an Activity context.

Answer 5

If you already have a valid context, just use this: Activity activity = (Activity) context;

Answer 6

There are many ways for Activities communication.

you can use:

• the startActivityForResult method

• a system of broadcast message and receiver (you can broadcast an event from the actual activity, and register a receiver in the target activity. Remember that the target activity must be previously initialized and non finished)

• as you say, store a reference of the target activity wherever you need.