Custom global Application class breaks with "android.app.Application cannot be cast to"

Question

I have a custom global class which looks like this

import android.app.Application;

public class MyApp extends Application {

    public String MainAct;

    public String getMainAct() {
        return MainAct;
    }

    public void setMainAct(String mainAct) {
        MainAct = mainAct;
    }
}

I want to preserve a string in this class via another Activity in its onCreate method.

    String local = "myLocalVariable";
    ((MyApp) getApplication()).setMainAct(local); //breaks here!!!
    String name = ((MyApp) getApplication()).getMainAct();

It breaks on the marked line with error: Caused by: java.lang.ClassCastException: android.app.Application cannot be cast to com.xxx.yyy.global.MyApp

I've checked the code for five times and I cannot find error anywhere. Can anyone tell me where the error is?!

Thanks

score 517 · Accepted Answer · answered May 15 '12 at 19:21

517

The error states that the type of the object returned by getApplication is android.app.Application. A possible cause for this is that you failed to define the application in the manifest. Make sure that your manifest includes something in the lines of:

<application android:name=".MyApp"...
</application>

answered May 15 '12 at 19:21

K-ballo

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9

Oh my God, you're right. And I've lost last hour trying to figure out why it does not want to work this time when it worked 100 times before :). Thanks a lot! – sandalone May 15 '12 at 19:27
11

2 years on, still saving lives – Vrashabh Irde Sep 29 '14 at 15:19
35

Hey. I have this added to my manifest. However, it is still giving me a ClassCastException – Somu Jul 31 '15 at 19:45
dohhh!! this one I forget everytime I start a new project lol. – James andresakis Jan 05 '16 at 21:51
15

Had the same problem minutes ago on Android N, the manifest was correct. Restarted the device - exception was gone. Strange... – artkoenig Oct 16 '16 at 11:50
3

@Somu clean cache, and close instant run, rebuild project, this worded for me, i think this is a bug of instant run. – LenaYan Oct 21 '16 at 02:47
I NEVER would have figured this out. Thank you so much! – John Crawford Apr 17 '17 at 15:08
Thanks a ton. U r a savior. – S P Oct 20 '17 at 12:26
1

@artkoenig Thank you for Information! Restart fixed the problem. I was trying to fix this issue. I checked with debugger, `getApplication()` and `getApplicationContext()` could not be casted to my `Application` class. – Ioane Sharvadze Feb 20 '18 at 15:54

Val · Answer 2 · 2016-10-30T17:57:04.250

17

Another solution for older Android devices or emulators. You defined an application in the manifest:

    <application 
           android:name=".MyApp"...
    </application>

but you still have this problem?

Try to disable instant run:

Disable an Instant run
Clean and rebuild the project
Remove the app from device and install it again without Instant run

edited Oct 30 '16 at 17:57

answered Oct 30 '16 at 17:51

Val

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Custom global Application class breaks with "android.app.Application cannot be cast to"

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