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Android

Posted by perpetual makayi
perpetual makayi
8,441 Points

fregments

Challenge Task 1 of 3

I created a new fragment to store our news items. It's called NewsItemFragment.java. When I went to add a constructor to pass in the selected index, Android Studio told me that I shouldn't do that.

Can you please help me by using a bundle to pass the index to my new NewsItemFragment when it is selected? (I added a constant key for the index in NewsItemFragment.java

Important: In each task of this code challenge, the code you write should be added to the code from the previous task.

MainActivity.java
NewsItemFragment.java
News.java

public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener {

// New tags for referring to fragments

public static final String NEWS_FRAGMENT = "news_fragment";

public static final String NEWSITEM_FRAGMENT = "newsitem_fragment";

​

​

@Override

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

​

    FragmentManager fragmentManager = getFragmentManager();

​

    NewsFragment savedFragment = (NewsFragment) fragmentManager.findFragmentById(R.id.placeholder);

​

    if (savedFragment == null) {

        NewsFragment newsFragment = new NewsFragment();

        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

        fragmentTransaction.add(R.id.placeholder, newsFragment);

        fragmentTransaction.commit();

    }

​

}

​

@Override

public void onNewsItemSelected(int index) {

    NewsItemFragment fragment = new NewsItemFragment();

    // TODO: how do we pass arguments to the new Fragment?



    FragmentManager fragmentManager = getFragmentManager();

    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

    fragmentTransaction.replace(R.id.placeholder, fragment);

    fragmentTransaction.addToBackStack(null);

    fragmentTransaction.commit();

}

}

​

2 Answers

TERRENCE MAVHUNGA
TERRENCE MAVHUNGA
6,053 Points
TERRENCE MAVHUNGA
TERRENCE MAVHUNGA
6,053 Points

public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener { // New tags for referring to fragments public static final String NEWS_FRAGMENT = "news_fragment"; public static final String NEWSITEM_FRAGMENT = "newsitem_fragment";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    FragmentManager fragmentManager = getFragmentManager();

    NewsFragment savedFragment = (NewsFragment) getSupportFragmentManager().findFragmentByTag(NEWS_FRAGMENT);

    if (savedFragment == null) {
        NewsFragment newsFragment = new NewsFragment();

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

}

@Override
public void onNewsItemSelected(int index) {
    NewsItemFragment fragment = new NewsItemFragment();
    // TODO: how do we pass arguments to the new Fragment?
     Bundle bundle = new Bundle ();
  bundle.putInt(NewsItemFragment.KEY_NEWS_ITEM_INDEX,index);

fragment.setArguments(bundle);

    FragmentManager fragmentManager = getFragmentManager();
 FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(R.id.placeholder, fragment,NEWSITEM_FRAGMENT);
    fragmentTransaction.addToBackStack(null);
    fragmentTransaction.commit();


}

}

//news Item

public class NewsItemFragment extends Fragment { public static final String KEY_NEWS_ITEM_INDEX = "news_item_index";

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    // TODO:  Hmmm, how do we get this index?
  int index = getArguments().getInt( NewsItemFragment.KEY_NEWS_ITEM_INDEX);
    getActivity().setTitle(News.headlines[index]);
    View view = inflater.inflate(R.layout.fragment_newsitem, container, false);
    return view;
}




@Override
public void onStop() {
    super.onStop();
    getActivity().setTitle(getResources().getString(R.string.app_name));
}

}

//news public class News { public static String[] headlines = new String[]{ "Treehouse student develops #1 App in Google App Store", "Oracle and Google decide to hug it out", "Java8 coming to Android! Is it too late?" }; }

Ngonidzashe Sahwenje
Ngonidzashe Sahwenje
12,936 Points

Hi Terrence, im still getting a bummer

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

I see you haven't tried to enter a solution yet. It would be a big help to see if there is something specific you are stuck on. If you're really stuck to the point you don't know where to begin, perhaps it would be better to review the previous video which goes over the way to do this.

Kamran Arshad
Kamran Arshad
9,312 Points

im getting an error ./MainActivity.java:13: error: cannot find symbol NewsFragment savedFragment = (NewsFragment) getSupportFragmentManager().findFragmentByTag(NEWS_FRAGMENT); ^ symbol: method getSupportFragmentManager() location: class MainActivity 1 error

public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener { // New tags for referring to fragments public static final String NEWS_FRAGMENT = "news_fragment"; public static final String NEWSITEM_FRAGMENT = "newsitem_fragment";

@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);

FragmentManager fragmentManager = getFragmentManager();

NewsFragment savedFragment = (NewsFragment) getSupportFragmentManager().findFragmentByTag(NEWS_FRAGMENT);

if (savedFragment == null) {
    NewsFragment newsFragment = new NewsFragment();

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

}

@Override public void onNewsItemSelected(int index) { NewsItemFragment fragment = new NewsItemFragment(); Bundle bundle = new Bundle (); bundle.putInt(NewsItemFragment.KEY_NEWS_ITEM_INDEX,index); fragment.setArguments(bundle);

FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.placeholder, fragment,NEWSITEM_FRAGMENT);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();

} }