get Activity object while in View context

Question

This is a followup to this post:

findViewById in a subclassed SurfaceView throwing RuntimeException

Based on Romain Guy\'s feedback (which I\'ll accept short

Answer 1

If you already know the Activity class your View is in, i.e. MyActivity, you can use the static member MyActivity.this from inside your View and its listeners, as in the following example:

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
       .setCancelable(false)
       .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
                MyActivity.this.finish();
           }
       })
       .setNegativeButton("No", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int id) {
                dialog.cancel();
           }
       });
AlertDialog alert = builder.create();

which I've found in this Android tutorial:

http://developer.android.com/guide/topics/ui/dialogs.html

It worked wonders for me.

PJ_Finnegan

Answer 2

An Activity is a Context, but there is no guarantee that the Context used by a View is always an Activity. Getting the views from onCreate() to do some setup is perfectly valid and is how Android applications are usually written. You could do something like this for instance:

setContentView(...);
MySurfaceView v = findViewById(R.id.theusrface);
TextView t = findViewById(R.id.thecontent);
v.setContent(v);

The logic should not go in your Views.