Can not resolve method 'findViewById(int)'

Question

I\'m having a trouble with findViewByid but I can\'t find where the problem is.

Here\'s my FirstFragment class code:

import and         


        

Answer 1

getActivity().findViewById() works. However, this isn't a good practice because the fragment may be reused in another activity.

The recommended way for this is to define an interface.

• The interface should contain methods by which the fragment needs to communicate with its parent activity.

  public interface MyInterfcae {
      void showTextView();
  }
  

• Then your activity implements that Interface.

  public class MyActivity extends Activity implements MyInterfcae {
      @Override
      public void showTextView(){
          findViewById(R.id.textview).setVisibility(View.VISIBLE);
      }
  }
  

• In that fragment grab a reference to the interface.

  MyInterface mif = (MyInterface) getActivity();
  

• Call a method.

  mif.showTextView();
  

This way, the fragment and the activity are fully decoupled and every activity which implements that fragment, is able to attach that fragment to itself.