Is it always safe to cast Context to Activity within View

Question

May I know, is it safe for me to always cast Context to Activity within a View?

View {
    Activity activity = (Activity)this.getContext();
}

So far, it works fine all the moment. I was wondering, is there any edge cases that the above code will fail?

score 57 · Answer 1 · answered Feb 14 '12 at 07:34

57

As I know, It is not always safe because, the context also can be passed from os to a Service, BroadcastReceiver, etc. But, almost of case, that is not a problem. just check with this code

if(context instanceof Activity)

and feel free to use.

answered Feb 14 '12 at 07:34

lulumeya

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score 7 · Answer 2 · answered Jul 28 '17 at 02:55

I think you can use following snippet:

/**
 * Get activity instance from desired context.
 */
public static Activity getActivity(Context context) {
    if (context == null) return null;
    if (context instanceof Activity) return (Activity) context;
    if (context instanceof ContextWrapper) return getActivity(((ContextWrapper)context).getBaseContext());
    return null;
}

score 3 · Answer 3 · answered Feb 14 '12 at 07:57

3

Technically, Views can be created with any Context (via the LayoutInflater)

So unless you are super sure that your Views are only instantiated by Activities, I wouldn't suggest this. Doing this is not a clean idea.

answered Feb 14 '12 at 07:57

Vikram Bodicherla

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score 2 · Accepted Answer · answered Feb 14 '12 at 07:35

2

While I can't think of such case, I think it is not such a great idea for two reasons:

Why would you want to do that, when do you explicitly need Activity?
What if tomorrow this will be changed, and there will be other context for View?

answered Feb 14 '12 at 07:35

MByD

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2

**1.** There are [situations](http://stackoverflow.com/a/5376772) in which the caller can't an Activity as a parameter. **2.** Android is pretty good in keeping backward compatibility (which I can't say about its development tools). IMHO @lulumeya's answer is the correct answer to be accepted. – ateiob Aug 07 '12 at 20:19
`ContextThemeWrapper` certainly adds a whole new level of nonsense to it. I've heard you can access the Activity using `getBaseContext()` then. – EpicPandaForce Feb 09 '16 at 10:36

Is it always safe to cast Context to Activity within View

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