如何自动使用班级名称？

Question

在下面的代码中，我可以代替Play.this编写什么，以便它可以自动使用使用该类的名称，而无需编写名称（在本例中为“ Play”） AlertDialog.Builder builder = new AlertDialog.Builder(Play.this);

Answer 1

There's no reason to use Play.this in code being part of Play class. Just use this :

AlertDialog.Builder builder = new AlertDialog.Builder(this);

However if you want to do that from your inner class, then you need this will not point to Context subclass, so you can ie create member in your parent class, ie:

Context mContext;

initialize it in ie onCreate() :

mContext= this;

and use mContext from your listener's code

AlertDialog.Builder builder = new AlertDialog.Builder(mContext);

Answer 2

There are other things to think before set the context (this).

First case - If you are in a class that extends a context in its base like Activity/Services, and you are NOT in a inner class, you can use just "this"

Second - If you are in a class that extends a context in its base like Activity/Services, and you are in a inner class, you can use (Play.this), because the "this" in this case, is about the inner class.

Third - If you are in another class that does not have a context, you can pass it in constructor or method like:

class Test {
   public void createBuilder(Context context) {
      AlertDialog.Builder builder = new AlertDialog.Builder(context);
   }
}

Answer 3

I think what you are looking for is this.getClass().getName() . If you want just the unqualified name, use this.getClass().getSimpleName() instead. I know very little about Android specifically, but that's how you would do it in Java in general.