ActivityName.this refers to activity context. getApplicationContext () refers to the application context.
Most of the times it is better to use activity context.
Check the answer provided by commonsware. Has a detail explanation on the topic.
When to call activity context OR application context?
Quote form the above link
Here are reasons why not to use getApplicationContext() wherever you go:
It's not a complete Context, supporting everything that Activity does. Various things you will try to do with this Context will fail, mostly related to the GUI.
It can create memory leaks, if the Context from getApplicationContext() holds onto something created by your calls on it that you don't clean up. With an Activity, if it holds onto something, once the Activity gets garbage collected, everything else flushes out too. The Application object remains for the lifetime of your process.
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