how to change fragment views programmatically from the parent activity

Question

I am having a fragment that contains for example one button, I want to allow the Activity containing the fragment to change this button view like for example color and title or

Answer 1

Try this way according to your requirement

public abstract class BaseFragment extends Fragment {
    BaseActivity yourActivity;
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

   @Override
   public void onAttach(Context context) {
       super.onAttach(context);
      yourActivity = (BaseActivity) context;
   }

   @Override
   public void onDetach() {
       yourActivity = null;
       super.onDetach();
    }


    public void refreshview(){} 

    public void setDada(Data data){}


    @override
    publicn void onStart(){
        yourActivity.setCurrentOpenedFragment(this);
    }
}

Create the BaseActivity class

public abstract class BaseActivity extends AppCompatActivity{
   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }
     public void setCurrentOpenedFragment(BaseFragment currentFragment){}
}

Extends the BaseFragment in your fragment i.e.

public class YourFragment extends BaseFragment{
   View view;       
   Button button;
   @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {       
          view = inflater.inflate(R.layout.fragment, container, false);
          button = (Button)view.findViewById(R.id.button);
          return view;
    }

    @override
    publicn void onStart(){
      super.onStart();
      //yourActivity.setCurrentOpenedFragment(this);
   }

   Data data; 
   @override 
   public void setDada(Data data){
     this.data = data;
   } 
    @Override 
    public void refreshview() {
       button.setcolor(data.getcolor());
    }
} 

Write the below line of code in your Activity class

public class YourActivity extends BaseActivity{

   public static final byte NONE =  -1;
   public static final byte HOME =  1;

   @Override
    protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
            setContentView(R.layout.your_activity);
            changeFragment(new YourFragment(), HOME);
            initview();
    }

   public void initview(){
        Button b = (Button)findViewById(R.id.button);
        b.setOnClickListener(new OnClickListener(){
          if(currentFragmentOnDrawer != null){

            Data data = new Data();
            data.setColor(getResource().getcolor(R.color.red));
            currentFragmentOnDrawer.setDada(data);

            currentFragmentOnDrawer.refreshview()

         }
       });
   }

   BaseFragment currentFragmentOnDrawer;
    @Override
    public void setCurrentOpenedFragment(BaseFragment currentFragment) {
        super.setCurrentOpenedFragment(currentFragment);
        this.currentFragmentOnDrawer = currentFragment;
    }

   public void changeFragment(Fragment targetFragment, byte state) {

      FragmentTransaction ft = getSupportFragmentManager()
            .beginTransaction();
      ft.replace(R.id.main_fragment, targetFragment, "" + state);
      ft.addToBackStack("" + state);
      ft.commit();
  }
}

Hope it will help for you

Answer 2

1. You must get you fragment from your activity

val fragment = supportFragmentManager.findFragmentByTag("tag")

or

val fragment = supportFragmentManager.findFragmentById(R.id.fragment)

2. Create a method that will do what you wants in you fragment and call this method from the activity

fragment.hideButton()

or you can use interface