How to get my activity context?

Solution 1:

Ok, I will give a small example on how to do what you ask

public class ClassB extends Activity
{

 ClassA A1 = new ClassA(this); // for activity context

 ClassA A2 = new ClassA(getApplicationContext());  // for application context. 

}

Solution 2:

You can use Application class(public class in android.application package),that is:

Base class for those who need to maintain global application state. You can provide your own implementation by specifying its name in your AndroidManifest.xml's tag, which will cause that class to be instantiated for you when the process for your application/package is created.

To use this class do:

public class App extends Application {

    private static Context mContext;

    public static Context getContext() {
        return mContext;
    }

    public static void setContext(Context mContext) {
        this.mContext = mContext;
    }

    ...

}

In your manifest:

<application
        android:icon="..."
        android:label="..."
        android:name="com.example.yourmainpackagename.App" >
                       class that extends Application ^^^

In Activity B:

public class B extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sampleactivitylayout);

        App.setContext(this);
                  ...
        }
...
}

In class A:

Context c = App.getContext();

Note:

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.

Solution 3:

The best and easy way to get the activity context is putting .this after the name of the Activity. For example: If your Activity's name is SecondActivity, its context will be SecondActivity.this

Solution 4:

you pass the context to class B in it's constructor, and make sure you pass getApplicationContext() instead of a activityContext()