Static way to get 'Context' in Android?

Do this:

In the Android Manifest file, declare the following.

<application android:name="com.xyz.MyApplication">

</application>

Then write the class:

public class MyApplication extends Application {

    private static Context context;

    public void onCreate() {
        super.onCreate();
        MyApplication.context = getApplicationContext();
    }

    public static Context getAppContext() {
        return MyApplication.context;
    }
}

Now everywhere call MyApplication.getAppContext() to get your application context statically.

The majority of apps that want a convenient method to get the application context create their own class which extends android.app.Application.

GUIDE

You can accomplish this by first creating a class in your project like the following:

import android.app.Application;
import android.content.Context;

public class App extends Application {

    private static Application sApplication;

    public static Application getApplication() {
        return sApplication;
    }

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

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

Then, in your AndroidManifest you should specify the name of your class in the AndroidManifest.xml’s tag:

<application 
    ...
    android:name="com.example.App" >
    ...
</application>

You can then retrieve the application context in any static method using the following:

public static void someMethod() {
    Context context = App.getContext();
}

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WARNING

Before adding something like the above to your project you should consider what the documentation says:

There is normally no need to subclass Application. In most situation, static singletons can provide the same functionality in a more modular way. If your singleton needs a global context (for example to register broadcast receivers), the function to retrieve it can be given a Context which internally uses Context.getApplicationContext() when first constructing the singleton.

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REFLECTION

There is also another way to get the application context using reflection. Reflection is often looked down upon in Android and I personally think this should not be used in production.

To retrieve the application context we must invoke a method on a hidden class (ActivityThread) which has been available since API 1:

public static Application getApplicationUsingReflection() throws Exception {
    return (Application) Class.forName("android.app.ActivityThread")
            .getMethod("currentApplication").invoke(null, (Object[]) null);
}

There is one more hidden class (AppGlobals) which provides a way to get the application context in a static way. It gets the context using ActivityThread so there really is no difference between the following method and the one posted above:

public static Application getApplicationUsingReflection() throws Exception {
    return (Application) Class.forName("android.app.AppGlobals")
            .getMethod("getInitialApplication").invoke(null, (Object[]) null);
} 

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Happy coding!

Assuming we're talking about getting the Application Context, I implemented it as suggested by @Rohit Ghatol extending Application. What happened then, it's that there's no guarantee that the context retrieved in such a way will always be non-null. At the time you need it, it's usually because you want to initialize an helper, or get a resource, that you cannot delay in time; handling the null case will not help you. So I understood I was basically fighting against the Android architecture, as stated in the docs

Note: There is normally no need to subclass Application. In most situations, static singletons can provide the same functionality in a more modular way. If your singleton needs a global context (for example to register broadcast receivers), include Context.getApplicationContext() as a Context argument when invoking your singleton's getInstance() method.

and explained by Dianne Hackborn

The only reason Application exists as something you can derive from is because during the pre-1.0 development one of our application developers was continually bugging me about needing to have a top-level application object they can derive from so they could have a more "normal" to them application model, and I eventually gave in. I will forever regret giving in on that one. :)

She is also suggesting the solution to this problem:

If what you want is some global state that can be shared across different parts of your app, use a singleton. [...] And this leads more naturally to how you should be managing these things -- initializing them on demand.

so what I did was getting rid of extending Application, and pass the context directly to the singleton helper's getInstance(), while saving a reference to the application context in the private constructor:

private static MyHelper instance;
private final Context mContext;    

private MyHelper(@NonNull Context context) {
    mContext = context.getApplicationContext();
}

public static MyHelper getInstance(@NonNull Context context) {
    synchronized(MyHelper.class) {
        if (instance == null) {
            instance = new MyHelper(context);
        }
        return instance;
    }
}

the caller will then pass a local context to the helper:

Helper.getInstance(myCtx).doSomething();

So, to answer this question properly: there are ways to access the Application Context statically, but they all should be discouraged, and you should prefer passing a local context to the singleton's getInstance().

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For anyone interested, you can read a more detailed version at fwd blog