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Android Android Fragments Introducing Fragments Handling Clicks

Posted by Eli Goodwin
Eli Goodwin
29,502 Points

Handling clicks

I am not sure what I am doing wrong here. Followed the pattern from the lesson, but I cannot figure out to implement the fragment interface.

NewsFragment.java 
public class NewsFragment extends Fragment {
    public interface NewsListener{
       void onNewsItemSelected(int index);
}
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_news, container, false);
        return view;
    }
}
MainActivity.java 
public class MainActivity extends AppCompatActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

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

2 Answers

Ben Deitch
STAFF
Ben Deitch
Treehouse Teacher
Ben Deitch
Ben Deitch
Treehouse Teacher

Hi Eli! You need to implement the 'NewsListener' interface in your MainActivity class. First, you need to declare that MainActivity does implement the interface:

public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener {

And then you just need to override the interface's method in MainActivity. Hope that helps!

Yvonne Mutangi
Yvonne Mutangi
4,618 Points

can i have a clear explanation of the code because i am lost

Ben Deitch
Ben Deitch
Treehouse Teacher
Ben Deitch
Ben Deitch
Treehouse Teacher

Sure!

First we need to create a new interface inside of the NewsFragment class:

public class NewsFragment extends Fragment {
    public interface NewsListener{
       void onNewsItemSelected(int index);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_news, container, false);
        return view;
    }
}

Then in MainActivity we implement this interface (which we access through the NewsFragment class) and override the 'onNewsItemSelected' method:

public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener {

    @Override
    public void onNewsItemSelected(int index) {

    }

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

        NewsFragment newsFragment = new NewsFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.placeholder, newsFragment);
        fragmentTransaction.commit();
    }
}
TERRENCE MAVHUNGA
TERRENCE MAVHUNGA
6,053 Points
TERRENCE MAVHUNGA
TERRENCE MAVHUNGA
6,053 Points

public class NewsFragment extends Fragment { public interface NewsListener{ void onNewsItemSelected(int index); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_news, container, false); return view; } }

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

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

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

perpetual makayi
perpetual makayi
8,441 Points

thank you it worked

Brenda Catherine Mugadza
Brenda Catherine Mugadza
3,708 Points

i have tried the above but i keep getting this error.

./MainActivity.java:1: error: MainActivity is not abstract and does not override abstract method onNewsItemSelected(int) in NewsListener public class MainActivity extends AppCompatActivity implements NewsFragment.NewsListener ^ 1 error