How to use interface to communicate between two activities
Have you considered using LocalBroadcastManager?
In Act1's onCreate:
act2InitReceiver= new BroadcastReceiver()
{
@Override
public void onReceive(Context context, Intent intent)
{
// do your listener event stuff
}
};
LocalBroadcastManager.getInstance(this).registerReceiver(act2InitReceiver, new IntentFilter("activity-2-initialized"));
In Act1's onDestroy:
LocalBroadcastManager.getInstance(this).unregisterReceiver(act2InitReceiver);
In Act2's onCreate:
LocalBroadcastManager.getInstance(this).sendBroadcast(new Intent("activity-2-initialized"));
Give me a comment if the code doesn't compile, I'm writing it by hand.
I would suggest to create a model class. Let me give you an example:
Model class:
public class CustomModel {
public interface OnCustomStateListener {
void stateChanged();
}
private static CustomModel mInstance;
private OnCustomStateListener mListener;
private boolean mState;
private CustomModel() {}
public static CustomModel getInstance() {
if(mInstance == null) {
mInstance = new CustomModel();
}
return mInstance;
}
public void setListener(OnCustomStateListener listener) {
mListener = listener;
}
public void changeState(boolean state) {
if(mListener != null) {
mState = state;
notifyStateChange();
}
}
public boolean getState() {
return mState;
}
private void notifyStateChange() {
mListener.stateChanged();
}
}
And here's how you would use this:
// Imports
public class MainActivity extends Activity implements OnCustomStateListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CustomModel.getInstance().setListener(this);
boolean modelState = CustomModel.getInstance().getState();
Log.d(TAG, "Current state: " + String.valueOf(modelState));
Intent intent = new Intent(this, SecondActivity.class);
startActivity(intent);
}
@Override
public void stateChanged() {
boolean modelState = CustomModel.getInstance().getState();
Log.d(TAG, "MainActivity says: Model state changed: " +
String.valueOf(modelState));
}
}
Changing the member state in second activity:
// Imports
public class SecondActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
CustomModel.getInstance().changeState(true);
}
}
LogCat output:
Current state: false
MainActivity says: Model state changed: true