Get application context returns null

Question

The following schema has been touted as the way to get application context from anywhere within my android app. But sometimes doing MyApp.getContext() returns null. I tried changing the schema by removing static from getContext() so that I would do MyApp.getInstance().getContext(). It still returns null. How do I fix this? How do I get my application's context from anywhere within my app?

public class MyApp extends Application {
    private static MyApp instance;

    public static MyApp getInstance() {
        return instance;
    }

    public static Context getContext() {
        return instance.getApplicationContext();
    }

    @Override
    public void onCreate() {
        super.onCreate();
        instance = this;
    }
}

`sometimes` Actually I believe it used to work, but in reality I couldn't tell you because right now it always crashes. so `sometimes` is just me being cautious. — learner, Feb 24 '14 at 17:29
What is the stacktrace when it crashes? Crashing is a very different behavior than returning null from a method. — Code-Apprentice, Feb 24 '14 at 17:29

score 55 · Accepted Answer · edited Jul 14 '22 at 07:53

55

Create in onCreate() an instance of getApplicationContext() (mContext) then call MyApp.getContext() from everywhere in your app and you will get your application context statically.

public class MyApp extends Application {
    private static Context mContext;

    public static Context getContext() {
        return mContext;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        mContext = getApplicationContext();    
    }
}

Remember to declare into your AndroidManifest.xml

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

edited Jul 14 '22 at 07:53

Sabrina

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answered Feb 24 '14 at 17:35

Jorgesys

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12

The link solved my problem. I was missing ``. Thanks. – learner Feb 25 '14 at 05:44
`return instance.getApplicationContext()` works fine, no need to use `return mContext`. Particularly when calling `instance.getApplicationContext()` from classes outside application in some cases like database, it is preferred to pass instance as context, and then call Application context. – Nagaraju Gajula Oct 28 '16 at 06:13
2

i have this warning "Do not place Android context classes in static fields; this is a memory leak ", how can i resolve this? – Hamid Zandi Jul 21 '17 at 17:43
1

@juzamn in services sometime Myapp.getContext through null pointer exception – baldraider Oct 14 '17 at 11:55
@do01 it's a application object. I don't think any leak willl affect application memory management. – Shubham AgaRwal Mar 29 '19 at 09:14

Sami Eltamawy · Answer 2 · 2015-05-14T05:36:20.640

12

Create a static instance of the Context in your OnCreate and keep it till you want to get it from a getter method getContext()

From the Application class:

public class MyApp extends Application {

private static Context sContext;
@Override
public void onCreate() {
    sContext = getApplicationContext();
    super.onCreate();
}

public static Context getContext() {
    return sContext;
}
}

Declare it in your Manifest:

<application android:name="com.package.name.MyApp">

edited May 14 '15 at 05:36

answered Feb 24 '14 at 17:33

Sami Eltamawy

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Thanks for helping. +1. I was missing `` – learner Feb 25 '14 at 05:44

score 2 · Answer 3 · edited Jul 14 '22 at 07:55

Use the following way to get the Application context.

public class MyApp extends Application {
    private static MyApp mAppInstance=null;
    public static Context appContext;

    public static MyApp getInstance() {
        return mAppInstance;
    }

    public static MyApp get() {
        return get(appContext);
    }

    public static MyApp get(Context context) {
        return (MyApp) context.getApplicationContext();
    }

    @Override
    public void onCreate() {
        super.onCreate();
        mAppInstance=this;
        appContext=getApplicationContext();
    }
}

add the the application name inside the Manifest file

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

to get the context use MyApp.getInstance().getApplicationContext()

score 1 · Answer 4 · answered Feb 24 '14 at 17:30

1

instance is never initialized and so has a default value of null. This means that instance.getContext() will throw a NullPointerException. To fix this, you need to initialize the instance variable.

answered Feb 24 '14 at 17:30

Code-Apprentice

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score 0 · Answer 5 · answered Feb 24 '14 at 17:33

0

Currently, you have not initialized instance and by default it's value would now be set to null. You need to assign it a value before you can use it.

answered Feb 24 '14 at 17:33

ucsunil

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score 0 · Answer 6 · answered Jan 13 '20 at 07:01

0

Another root cause, is due to the buggy backup process. Please refer to

Why backup related process might cause Application's onCreate is not executed?

answered Jan 13 '20 at 07:01

Cheok Yan Cheng

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score 0 · Answer 7 · answered Apr 13 '22 at 19:45

0

For get an application context the module should use the application plugin.

build.gradle (:module)

apply plugin: 'com.android.application'

The library plugin has not an app context.

answered Apr 13 '22 at 19:45

Braian Coronel

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Get application context returns null

7 Answers7

build.gradle (:module)

Linked

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