MainFragment.java

public class AppRestrictionSchemaFragment extends Fragment implements View.OnClickListener
{

  private static final String KEY_CAN_SAY_HELLO = "can_say_hello";
  
  @Override
  public void onViewCreated(View view, @Nullable Bundle savedInstanceState) 
  {
      mTextSayHello = (TextView) view.findViewById(R.id.say_hello_explanation);
      mButtonSayHello.setOnClickListener(this);
  }
  
  @Override
  public void onResume() {
      super.onResume();
      resolveRestrictions();
      updateCanSayHello();
  }
  
  @Override
  public void onStart() 
  {
      super.onStart();
      // We need to create a broadcast receiver for ACTION_APPLICATION_RESTRICTIONS_CHANGED which send out a broadcast when restrictions change
      mBroadcastReceiver = new BroadcastReceiver() {
          @Override
          public void onReceive(Context context, Intent intent) 
          {
              resolveRestrictions();
              updateCanSayHello();
          }
      };
      getActivity().registerReceiver(mBroadcastReceiver,new IntentFilter(Intent.ACTION_APPLICATION_RESTRICTIONS_CHANGED));
    }
    
    @Override
    public void onStop()
    {
        super.onStop();
        if (mBroadcastReceiver != null) {
            getActivity().unregisterReceiver(mBroadcastReceiver);
            mBroadcastReceiver = null;
        }
    }
    
    @Override
    public void onClick(View view) 
    {
        switch (view.getId()) 
        {
            case R.id.say_hello: 
            {
                Toast.makeText(getActivity(), getString(R.string.message, mMessage),
                        Toast.LENGTH_SHORT).show();
                break;
            }
        }
    }
    
}