Ndtyjky

I have one activity and three fragments. In fragment(1), i have a chronometer that works perfectly. Firstly, i click chronometer start button. When chronometer shows 00:10, i open fragment(2). Then i return after 6 seconds, chronometer shows 00:00. I want it to show 00:16 and keep working while i changing fragments.

Fragment (1) xml.

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

>



<Chronometer

    android:id="@+id/chronometer"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:layout_alignParentTop="true"

    android:layout_centerHorizontal="true"

    android:layout_marginTop="25dp"

    android:textSize="70dp"

    android:textColor="#fff"

    />



<Button

    android:id="@+id/btn_Start"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="Start"

    android:layout_centerHorizontal="true"

    android:layout_marginTop="20dp"

    android:layout_below="@+id/chronometer"

    android:background="@drawable/btn_bg"

    android:textColor="#fff"

    />



<Button

    android:id="@+id/btn_Pause"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="Pause"

    android:layout_centerHorizontal="true"

    android:layout_below="@+id/btn_Start"

    android:background="@drawable/btn_bg"

    android:layout_marginTop="20dp"

    android:textColor="#fff"/>



<Button

    android:id="@+id/btn_Reset"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:text="Reset"

    android:layout_centerHorizontal="true"

    android:layout_below="@+id/btn_Pause"

    android:background="@drawable/btn_bg"

    android:layout_marginTop="20dp"

    android:textColor="#fff"/>



<Button

    android:id="@+id/btn_Back"

    android:layout_width="50dp"

    android:layout_height="wrap_content"

    android:layout_alignTop="@+id/btn_Reset"

    android:layout_alignParentStart="true"

    android:layout_alignParentLeft="true"

    android:layout_marginLeft="20dp"

    android:layout_marginTop="0dp"

    android:background="@drawable/btn_bg_2"

    android:drawableRight="@drawable/ic_fast_rewind_black_24dp"

    android:textColor="#fff" />



<Button

    android:id="@+id/btn_Forward"

    android:layout_width="50dp"

    android:layout_height="wrap_content"

    android:layout_alignTop="@+id/btn_Reset"

    android:layout_alignParentRight="true"

    android:layout_marginRight="30dp"

    android:background="@drawable/btn_bg_2"

    android:drawableLeft="@drawable/ic_fast_forward_black_24dp"

    android:textColor="#fff" />



</RelativeLayout>

This is my fragment(1) java code.

public class HomeFragment extends Fragment {





private Button btn_start;

private Button btn_pause;

private Button btn_reset;

private Button btn_back;

private Button btn_forward;





@Nullable

@Override

public View onCreateView(@NonNull LayoutInflater inflater, @Nullable 

ViewGroup container, @Nullable Bundle savedInstanceState) {

    View view= inflater.inflate(R.layout.fragment_home, container, false);







    chronometer = view.findViewById(R.id.chronometer);

    chronometer.setFormat("%s");



    btn_forward= view.findViewById(R.id.btn_Forward);

    btn_back = view.findViewById(R.id.btn_Back);

    btn_start= view.findViewById(R.id.btn_Start);

    btn_pause= view.findViewById(R.id.btn_Pause);

    btn_reset= view.findViewById(R.id.btn_Reset);



    btn_back.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {

            backChronometer();

        }

    });



    btn_forward.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {

            forwardChronometer();

        }

    });



    btn_start.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {

            startChronometer();

        }

    });



    btn_pause.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {

            pauseChronometer();

        }

    });



    btn_reset.setOnClickListener(new View.OnClickListener() {

        @Override

        public void onClick(View view) {

            pauseChronometer();

            resetChronometer();

        }

    });



    return view;

}

}

This is chronometer java code. (methods)

public class Chronometer {



public static long pauseOffset;

public static boolean running;



public static void startChronometer (){

    if(!running){

        chronometer.setBase(SystemClock.elapsedRealtime() - pauseOffset);

        chronometer.start();

        running = true;

    }



}

public static void pauseChronometer (){



    if (running){

        pauseOffset = SystemClock.elapsedRealtime() - chronometer.getBase();

        chronometer.stop();

        running = false;

    }



}

public static void resetChronometer (){



    chronometer.setBase(SystemClock.elapsedRealtime());

    pauseOffset = 0;

}

public static void forwardChronometer (){

    if (running) {

        chronometer.setBase(chronometer.getBase()-1000);

    }

}

public static void backChronometer (){

    if (running) {

        chronometer.setBase(chronometer.getBase()+1000);

    }

}

}

MainActivity java code.

public class MainActivity extends AppCompatActivity {



public static Chronometer chronometer;

public static TextView tv_rune;

public static SeekBar sb_rune;

public static int minrune = 0, maxrune = 35, currentrune;



@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);





    BottomNavigationView bottomNav = findViewById(R.id.bottom_navigation);

    bottomNav.setOnNavigationItemSelectedListener(navListener);



    getSupportFragmentManager().beginTransaction().replace(R.id.main_frame, 

new HomeFragment()).commit();



}

private BottomNavigationView.OnNavigationItemSelectedListener navListener =

        new BottomNavigationView.OnNavigationItemSelectedListener() {

            @Override

            public boolean onNavigationItemSelected(@NonNull MenuItem 

menuItem) {



                Fragment selectedFragment = null;



                switch (menuItem.getItemId()){

                    case R.id.navigation_home:

                        selectedFragment = new HomeFragment();

                        break;



                    case R.id.navigation_notifications:

                        selectedFragment = new NotificationsFragment();

                        break;



                    case R.id.navigation_info:

                        selectedFragment = new InfoFragment();

                        break;

                }





getSupportFragmentManager().beginTransaction().replace(R.id.main_frame,

                        selectedFragment).commit();



                return true;

            }

        };



}

Also I want to keep seekbar datas from fragment(2) to use them in fragment (1).
Actually, I wonder how can we keep data protected.

Try using setRetainInstance(true) in onCreate of the fragment, as described here.

https://stackoverflow.com/a/22884377/5343907

Maybe this suits your needs.

Android: How to restore the state of a stopped chronometer after rotation?