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Android Android Fragments Introducing Fragments Saving State

Posted by Esinah Mutseta
Esinah Mutseta
4,717 Points

i'm failing to pass this task please help

We need to make sure that we aren't recreating our NewsFragment if it already exists. Inside onCreate, create a new variable to store our saved NewsFragment and use 'findFragmentById' (with an id of 'R.id.placeholder') to set it.

MainActivity.java 
public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        NewsFragment savedFragment = (NewsFragment)getFragmentManager().findFragmentById(R.id.placeholder);
        if(savedFragment==null) { 

        NewsFragment newsFragment = new NewsFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.placeholder, newsFragment);
        fragmentTransaction.commit();
    }

    @Override
  public void onNewsItemSelected(int index) {
  }
}

2 Answers

mongst
mongst
10,841 Points
mongst
mongst
10,841 Points

Spoiler Alert:

public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        NewsFragment savedFragment = (NewsFragment)getFragmentManager().findFragmentById(R.id.placeholder);
        if(savedFragment==null) { 

        NewsFragment newsFragment = new NewsFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.placeholder, newsFragment);
        fragmentTransaction.commit();
    }
    }
    @Override
  public void onNewsItemSelected(int index) {
  }
}
Christopher Augg
Christopher Augg
21,223 Points
Christopher Augg
Christopher Augg
21,223 Points

Esinah,

The provided code already creates a fragment manager named fragmentManager. Therefore, we can order our code to use it for both fragments. Then we try to get a saved fragment with findFragmentById, test if it returns null, and only create a new fragment if does.

        FragmentManager fragmentManager = getFragmentManager();
        NewsFragment saveNewsFragment = (NewsFragment)fragmentManager.findFragmentById(R.id.placeholder);       

        if(saveNewsFragment == null) {

          NewsFragment newsFragment = new NewsFragment();        
          FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
          fragmentTransaction.add(R.id.placeholder, newsFragment);
          fragmentTransaction.commit();        
        }

Hope this helps,

Chris

Esinah Mutseta
Esinah Mutseta
4,717 Points

thanx Chris..i figured it out was just missing a second bracket after the commit command..