How to run startActivity from outside of the main activity

Question

I have a MainActivity class which has a NotificationsListener (seperate class). When a notification appears, it calls my gethtml class. They both extend Activity but the startActivity in my gethtml class doesn't work... (If I copy and test this code in my MainActivity , it works fine)... Anyone have an idea why it isn't working?

This is the main class:

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    IntentFilter filter = new IntentFilter();
    filter.addAction("com.kpbird.nlsexample.NOTIFICATION_LISTENER_EXAMPLE");
    startService(new Intent(MainActivity.this, NLService.class));
    Intent intent=new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
    startActivity(intent);        

    }

@Override
protected void onDestroy() {
    super.onDestroy();

}
}

This is the notification listener:

public class NLService extends NotificationListenerService {

@Override
public void onCreate() {
    super.onCreate();
    IntentFilter filter = new IntentFilter();
    filter.addAction("com.kpbird.nlsexample.NOTIFICATION_LISTENER_SERVICE_EXAMPLE");
}

@Override
public void onDestroy() {
    super.onDestroy();
}

@Override
public void onNotificationPosted(StatusBarNotification sbn) {   
    new Thread(new Runnable() {             
            public void run(){
            Looper.prepare();
            int cangethtml = 1;
                try{
                    if(cangethtml==1){
                        cangethtml = 0; //only runs once
                        new html();
                    }
                }finally{Looper.loop();}  
            }; 
        }).start();    
    }

@Override
public void onNotificationRemoved(StatusBarNotification sbn) {}
}

This is the final class which doesn't open the website through the startActivity :

public class html extends Activity{
public html()  {
    try {
                Intent i2 = new Intent("android.intent.action.MAIN");
                i2.setComponent(ComponentName.unflattenFromString("com.android.chrome/com.android.chrome.Main"));
                i2.addCategory("android.intent.category.LAUNCHER");
                i2.setData(Uri.parse("https://wwww.google.com"));
                startActivity(i2);

    }   finally{}
}
}

Answer 1

You need the context of the Activity. startActivity will be called in the context of Activity .

Answer 2

With reference to the developer's forum:

You should write

Context.startActivity(i2);

instead of

startActivity(i2);

Plus, make sure you don't forget to have a corresponding <activity> declaration in your package's AndroidManifest.xml .

For instance: Check in AndroidManifest.xml for all the classes defined by you. You have:

<activity android:name="packageName.className"/>

If your html class is not defined in AndroidManifest.xml , you can not access the methods and layouts defined in it.