Reputation: 607

Send live data from Main Activity to Fragment

I have this bluetooth headset which sends messages everytime to the main Activity. Within the main activity, I have a handler which will process these messages and output accordingly.

I have a fragment which will make use of the messages. I cannot find a way to send live data from MainActivity to the fragment and I don't want to copy/paste the handler code to the fragment.

Is there a way to send live data from the mainActivity to the fragment. I am including some code for you to better understand.

MainActivity

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_dashboard);
        //Bluetooth headset which send live data
        tgDevice = new TGDevice(bluetoothAdapter, handler);
        tgDevice.connect(false);
    }


/**
 * Handles messages from TGDevice
 * @param menu
 * @return
 */
private final Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        switch (msg.what) {
            case TGDevice.MSG_STATE_CHANGE:

                switch (msg.arg1) {
                    case TGDevice.STATE_IDLE:
                        break;
                    case TGDevice.STATE_CONNECTING:
                        //androidVersion.setText("Connecting...\n");
                        break;
                    case TGDevice.STATE_CONNECTED:
                        //androidVersion.setText("Connected" + "\t" +wifiInfo.getSSID());
                        tgDevice.start();
                        break;
                    case TGDevice.STATE_NOT_FOUND:
                        //tv.append("Can't find\n");
                        break;
                    case TGDevice.STATE_NOT_PAIRED:
                        //tv.append("not paired\n");
                        break;
                    case TGDevice.STATE_DISCONNECTED:
                        //tv.append("Disconnected\n");
                }

                break;
            case TGDevice.MSG_POOR_SIGNAL:
                poorSignalValue = msg.arg1;
                actionBar.setTitle("Signal: " + poorSignalValue);
                Log.v("Poor", "Signal: " + poorSignalValue + "\n");
                break;
            default:
                break;
        }
    }
};

The Fragment will make use of the poorsignal as well as other variables. What is the best way to do this? Other fragments will also make use of the TGDevice.

Upvotes: 0

Answers (4)

silent_control

Reputation: 612

You can use Android View Model and Live data to share achieve the desired behaviour.

//View model
    public class SharedViewModel extends ViewModel {
        private final MutableLiveData<Item> selected = new MutableLiveData<Item>();

        public void select(Item item) {
            selected.setValue(item);
        }

        public LiveData<Item> getSelected() {
            return selected;
        }
    }
    //Fragment
    public class MasterFragment extends Fragment {
        private SharedViewModel model;
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            model = ViewModelProviders.of(getActivity()).get(SharedViewModel.class);

        }
    }

Make sure you pass ViewModelProviders.of(getActivity()) instead of ViewModelProviders.of(this) when calling from fragment.

For more information: https://developer.android.com/topic/libraries/architecture/viewmodel.html#sharing

Upvotes: 0

ilan

Reputation: 4462

look in this link: http://developer.android.com/training/basics/fragments/communicating.html

you can call a function of the fragment from your main activity.

public class Main extends FragmentActivity{
   MyFragment articleFrag = (MyFragment)
            getSupportFragmentManager().findFragmentById(R.id.fragment_id);

 MyFragment.function();
}

public class MyFragment extends Fragment{
    ....

    public void function(){
       //do something ....
    }

}

Upvotes: 0