Fragment 예제

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <fragment
        android:id="@+id/fragment_color_list"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:name="com.example.fragmentex.ColorListFragment"
        />
    <fragment
        android:id="@+id/fragment_color"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:name="com.example.fragmentex.ColorFragment"
        />
</LinearLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity
                          implements ColorListFragment.onColorSelectedListener {

    private ColorFragment mColorFragment;

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

        mColorFragment = (ColorFragment) getSupportFragmentManager()
                .findFragmentById(R.id.fragment_color);
        mColorFragment.setColor(Color.RED);
    }

    @Override
    public void onColorSelected(int color) {
        mColorFragment.setColor(color);
    }
}

ColorListFragment.java

public class ColorListFragment extends ListFragment {

    private onColorSelectedListener mListener;

    interface onColorSelectedListener{
        void onColorSelected(int color);
    }

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        try{
            mListener = (onColorSelectedListener) context;
        }catch (ClassCastException e){
            throw new ClassCastException(((Activity) context).getLocalClassName()+
                    "는 OnClolorSelectedListener를 구현해야 합니다.");
        }
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        List<String> colorList = Arrays.asList("Red", "Green", "Blue");
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1,colorList);
        setListAdapter(adapter);
    }

    @Override
    public void onListItemClick(@NonNull ListView l, @NonNull View v, int position, long id) {
        //프래그먼트에 있는 어뎁터를  가져온다.
        ArrayAdapter<String> adapter = (ArrayAdapter<String>) l.getAdapter();
        String colorString = adapter.getItem(position);
        int color = Color.RED;
        switch (colorString){
            case "Red":
                color = Color.RED;
                break;
            case "Green":
                color = Color.GREEN;
                break;
            case "Blue":
                color = Color.BLUE;
                break;
        }
        if(mListener != null)
            mListener.onColorSelected(color);
    }
}

ColorFragment.java

public class ColorFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
		@Nullable Bundle savedInstanceState) {
        return new View(getActivity());
    }

    //색상추가
    public void setColor(int color){
        getView().setBackgroundColor(color);
    }
}