nontravis

//In Fragment    

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

        ...

        if( savedInstanceState != null ){
            onRestoreInstanceState( savedInstanceState ); // Restore Instance State here

nontravis

abstract public class BaseViewGroup extends FrameLayout{

    ...

    @Override
    protected void dispatchSaveInstanceState( SparseArray<Parcelable> container ){
        dispatchFreezeSelfOnly( container );
    }

    @Override

nontravis

abstract public class BaseViewGroup extends FrameLayout{

    ...

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (!(state instanceof ChildSavedState)) {
            super.onRestoreInstanceState(state);
            return;
        }

nontravis

abstract public class BaseViewGroup extends FrameLayout{

    ...

    public static abstract class ChildSavedState extends BaseSavedState{
        SparseArray childrenStates;

        public ChildSavedState( Parcelable superState ){
            super( superState );
        }

nontravis

public class SwitchViewGroup extends BaseViewGroup{
    ...
    @Override
    public Parcelable onSaveInstanceState(){
        Parcelable superState = super.onSaveInstanceState();
        // Must call
        SavedState ss = (SavedState) onSaveInstanceChildState( new SavedState( superState ) );
        //save data here
      
        return ss;

nontravis

public class SwitchViewGroup extends BaseViewGroup{
    ...
    private static class SavedState extends ChildSavedState{

        SavedState( Parcelable superState ){
            super( superState );
        }

        private SavedState( Parcel in, ClassLoader classLoader ){
            super( in, classLoader );

nontravis

class MainActivity extends Activity{

  public void calculateSomeValue(int value){
    int result = getPresenter().calculate(value);
    
    if(result > 0){
      // some logic 1
    }else if(result < 0){
      // some logic 2
    }else{

nontravis

@RunWith(AndroidJUnit4.class)
@LargeTest
class MainActivityUnitTest{
  
  @Before
  public void setup(){
    ...
  }

  @Test

nontravis

class MainPresenter{

  public int calculate(int value){
    // some logic
    ...
  }
  
  public void clickGotoSecondActivity(){
    // some logic
    ...

nontravis

@RunWith(JUnit4.class)
class MainPresenterUnitTest{
  
  @Before
  public void setup(){
    ...
  }

  @Test
  public void calculate(){