WeakReference.get() returns null after being checked for it

Issue

I have an async task executed from a view and in its onPostExecute I retrieve an instance of the view using weakReference.get() and I check that this instance is different from null. Later in the onPostExecute I call a method from weakReference.get() and I get a NullPointerException.

1. Would it be solved by calling it from the reference I got?

2. Is there any way in which the weakReference.get() value will differ from the reference I got at the start?

For example is it possible that the method() call of the view will lead to a NullPointerException?

Sample :

private WeakReference<View> weakReference;

[...]

@Override
protected void onPostExecute(Boolean result) {    
    View v = weakReference.get();
    if (v == null) {
        return;
    }
    […]
    getView().method();
}

Thank you very much.

Solution

Q1: Would it be solved by calling it from the reference I got?

Yes, it'll be solved by calling it from reference. So that, if reference is null, handle it or else use it as method() calling.

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Q2: Is there any way in which the weakReference.get() value will differ from the reference I got at the start?

Yes, if there's any configuration changes happens (activity/fragment recreates itself), means that view is recreated and your old view reference would be null.

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Conclusion: It's good practice to have reference of your view and perform any operation from that reference further

Answered By - Jeel Vankhede