Question

I have a TabHost with two child activities in it (in two tabs). I also implemented a public function in one of these activities that i would like to call from my parent (TabHost), to trigger some action within the tab.

Is it possible to reference the activity itself from the TabHost to call a public function?

Thanks

here is my tabhost setup:

    res = getResources(); 
    tabHost = getTabHost(); 

    TabHost.TabSpec spec; 
    Intent intent;  

    intent = new Intent().setClass(this, home.class);
    spec = tabHost.newTabSpec("home").setIndicator("Groups", res.getDrawable(R.drawable.groups)).setContent(intent);
    tabHost.addTab(spec);
    intent = new Intent().setClass(this, messages.class);
    spec = tabHost.newTabSpec("messages").setIndicator("Messages", res.getDrawable(R.drawable.messages)).setContent(intent);    
    tabHost.addTab(spec);

Answer 1

My approach would be to define a nested ‘listener’ class in the child activity which extends BroadcastReceiver.

I would then simply broadcast an Intent from my TabActivity which would then trigger the BroadcastReceiver to perform the action.

EDIT: To give example code…

The steps are…

1. Define the intent filter in the manifest
2. Add the nested ‘listener’ to the child activity
3. Set onResume()/onPause() in child activity to register/unregister the listener
4. Create intent in TabActivity and broadcast it when you want child to do something

In AndroidManifest.xml

<activity
    android:name=".MyActivity"
    android:label="@string/app_name"
    <intent-filter>
        <action android:name="com.mycompany.myApp.DO_SOMETHING" />
    </intent-filter>
</activity>

In MyActivity.java

public class MyActivity extends Activity {

    private MyListener listener = null;
    private Boolean MyListenerIsRegistered = false;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreated(savedInstanceState);

        listener = new MyListener();
    }

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

        if (!MyListenerIsRegistered) {
            registerReceiver(listener, new IntentFilter("com.mycompany.myApp.DO_SOMETHING"));
            MyListenerIsRegisterd = true;
        }
    }

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

        if (MyListenerIsRegistered) {
            unregisterReceiver(listener);
            MyListenerIsRegistered = false;
        }
    }

    // Nested 'listener'
    protected class MyListener extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {

            // No need to check for the action unless the listener will
            // will handle more than one - let's do it anyway
            if (intent.getAction().equals("com.mycompany.myApp.DO_SOMETHING")) {
                // Do something
            }
        }
    }
}

In the main TabActivity

private void MakeChildDoSomething() {

    Intent i = new Intent();
    i.setAction("com.mycompany.myApp.DO_SOMETHING");
    sendBroadcast(i);
}