单击一个选项卡中的按钮，然后在注释器选项卡中更改textview

Question

I have tab1 and tab3 also these have their classes and I want to click button in tab1 and change textview in the tab3, but I couldn't find anyway. This is my tab1 class

public class tab1Contacts extends Fragment{

    TextView tv;
    EditText et;
    TextView tv3;
    personInfo pı;

    public  personInfo returnpı(){
        return pı;
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.tab1contents, container, false);

        Button btn_jog = (Button) rootView.findViewById(R.id.jogging_button);


        tv = (TextView) rootView.findViewById(R.id.newRecordText);
        et = (EditText) rootView.findViewById(R.id.durationtext) ;
        pı = new personInfo();
        pı.eyesPower = 100;
        pı.brainPower = 100;
        pı.armsPower = 100;
        pı.legsPower = 100;
        pı.hearthPower = 100;
        pı.energyLevel = 100;
        pı.calorie = 2000;
        pı.condition = 0;

            btn_jog.setOnClickListener(new View.OnClickListener()
            {
                @Override
                public void onClick(View v)
                {
                    int duration = Integer.parseInt(et.getText().toString());
                    pı.jogging(duration);
                    //I want to change here textview in the tab3.
                }
            });
        return rootView;
    }
}

This also my tab3 Class:

public class Tab3Contacts extends Fragment {

    TextView tv3;
    double newBrainpower;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.tab3contents, container, false);
        tv3 = (TextView) rootView.findViewById(R.id.list_text) ;


        return rootView;
    }
}

Answer 1

 btn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
     //pager.setCurrentItem(yourindex);// if you use pager
     getTabHost().setCurrentTab(yourindex);

    }
});

Answer 2

If I'm reading your question correctly, then what you need is for tab3 to listen to events from tab1. For that you will want to implement some kind of internal notification/eventing system. This is typically handled through a notification handling class that will register observers/listeners.

An example from a project I've been maintaining:

public class NotificationManager {
    public interface Observer {
        public void update(String notificationName, Bundle data);
    }

    private static NotificationManager singletonNotifier = null;
    private HashMap<String, ArrayList<Observer>> mObservables = null;

    private NotificationManager() {
        mObservables = new HashMap<String, ArrayList<Observer>>();
    }

    //enforce singleton
    public static NotificationManager getInstance() {
        if (singletonNotifier == null) {
            singletonNotifier = new NotificationManager();
        }
        return singletonNotifier;
    }

    public void addObserver(String notificationName, Observer observer) {
        // add to map 
        // in multi-threaded apps make sure you use synchronized or a mutex
    }

    public void removeObserver(String notificationName, Observer observer) {
        // remove from map; mind threading
        // overload as necessary for your design
    }

    public void notifyObservers(String notificationName, Bundle data) {
        // go through your map of observers, build an array of observers
        // that need to update, then for each observer, call 
        // observer.update(notificationName, data);
    }
}

Then your tab3 class would need to implement the Observer interface and on object construction register itself with the NotificationManager with a string value for the type of notification it wants (use best practices for constants instead of string literal arguments), using the call

NotificationManager.getInstance().addObserver("Tab1DataChange", this);

It will need to implement the update(String, Bundle) method, which will make all the changes that you need. Then in the class for the tab1 object, add to the click listener this call:

NotificationManager.getInstance().notifyObservers("Tab1DataChange", data);

Where data is any information that observers would need to know to respond. In keeping with the idea of decoupling code, do not put together a data bundle that is explicitly for one listener, because at some point you might need something else to listen for the same event. Save yourself some grief now by designing the data bundle to contain what would need to update regardless of who is consuming the event.

Some lessons learned for me: Pay attention to Android lifecycle. OnPause and OnDestroy for the active view(s) should unregister the listener so that you don't end up with a null pointer exception if something triggers that event while the observer object is not available. OnCreate and OnResume should reregister. In some cases I have been able to not worry about OnPause/OnResume, but depending on your app you may need them.