Question

5554:Nexus 4 APL23 25:31 App Description In this lab, you will develop a Tour guide App. The app introduces basic information about Canadian cities to the user. You may change the contents to something else like a description of UWin campus buildings or sightseen locations in Windsor, etc. The app has one activity and two fragments, as shown in Fig. 1. When a user clicks on a city name in the top list fragment, the description appears in the second fragment. The app uses a bundle object to save state data to preserve the current Ul state so that it doesn't change when users rotate the device. Tour Guide 1 Calgary 2 Victoria 3 Vancouver 4 Toronto Calgary, a cosmopolitan Alberta city with numerous skyscrapers, owes its rapid growth to its status as the centre of Canada's oil industry. However, it's still steeped in the western culture that earned it the nickname "Cowtown," evident in the Calgary Stampede, its massive July rodeo and festival that Design Requirements The App should meet the following design requirements: 1. Use the Linear Layout for the main activity 2. Use list fragment for the top panel and a blank fragment for the bottom panel. 3. All strings should be saved in strings.xml. 4. Use bundle objects to save state data to preserve the current Ul state at orientation change.

Answer 1

Here are the required code. Create these files and put respective code in them in Android Studio. Data is mock. Put your own data accordingly. Feel free to reach out in case of any issues.

MainActivity.java:

public class MainActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ContentFragment contentFragment = new ContentFragment();
    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    transaction.add(R.id.top_frame, new CityFragment(contentFragment));
    transaction.commit();

    transaction = getSupportFragmentManager().beginTransaction();
    transaction.add(R.id.bottom_frame, contentFragment);
    transaction.commit();
  }
}

CityFragment.java:

/**
 * A fragment representing a list of Items.
 */
public class CityFragment extends Fragment {

  private OnListFragmentInteractionListener mListener;

  /**
   * Mandatory empty constructor for the fragment manager to instantiate the
   * fragment (e.g. upon screen orientation changes).
   */
  public CityFragment() {
  }

  CityFragment(ContentFragment contentFragment) {
    mListener = contentFragment;
  }

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
  }

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

    // Set the adapter
    if (view instanceof RecyclerView) {
      Context context = view.getContext();
      RecyclerView recyclerView = (RecyclerView) view;
      recyclerView.setLayoutManager(new LinearLayoutManager(context));
      recyclerView.setAdapter(new MyCityRecyclerViewAdapter(
          Arrays.asList(context.getResources().getStringArray(R.array.cities)), mListener
      ));
    }
    return view;
  }

  /**
   * This interface must be implemented by activities that contain this
   * fragment to allow an interaction in this fragment to be communicated
   * to the activity and potentially other fragments contained in that
   * activity.
   */
  public interface OnListFragmentInteractionListener {
    void onListFragmentInteraction(int position);
  }
}

ContentFragment.java:

public class ContentFragment extends Fragment implements CityFragment.OnListFragmentInteractionListener {

    private View view = null;
    private List<String> descriptions;
    public ContentFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.fragment_content, container, false);
        descriptions = Arrays.asList(view.getContext().getResources().getStringArray(R.array.descriptions));
        return view;
    }

    @Override
    public void onListFragmentInteraction(int position) {
        if(null != view)
            ((TextView)view.findViewById(R.id.description)).setText(descriptions.get(position));
    }
}

MyCityRecyclerViewAdapter:

public class MyCityRecyclerViewAdapter extends RecyclerView.Adapter<MyCityRecyclerViewAdapter.ViewHolder> {

  private final List<String> mValues;
  private final OnListFragmentInteractionListener mListener;

  MyCityRecyclerViewAdapter(List<String> items, OnListFragmentInteractionListener listener) {
    mValues = items;
    mListener = listener;
  }

  @NonNull
  @Override
  public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext())
        .inflate(R.layout.fragment_city, parent, false);
    return new ViewHolder(view);
  }

  @Override
  public void onBindViewHolder(final ViewHolder holder, final int position) {
    holder.mIdView.setText(String.valueOf(position));
    holder.mContentView.setText(mValues.get(position));

    holder.mView.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        if (null != mListener) {
          // Notify the active callbacks interface (the activity, if the
          // fragment is attached to one) that an item has been selected.
          mListener.onListFragmentInteraction(position);
        }
      }
    });
  }

  @Override
  public int getItemCount() {
    return mValues.size();
  }

  public static class ViewHolder extends RecyclerView.ViewHolder {
    final View mView;
    final TextView mIdView;
    final TextView mContentView;

    ViewHolder(View view) {
      super(view);
      mView = view;
      mIdView = view.findViewById(R.id.item_number);
      mContentView = view.findViewById(R.id.content);
    }

    @NonNull
    @Override
    public String toString() {
      return super.toString() + " '" + mContentView.getText() + "'";
    }
  }
}

AndroidManifest.xml (only change the activity tag to be like this and not the whole file):

<activity
    android:name=".MainActivity"
    android:configChanges="keyboardHidden|orientation">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />

        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

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">

    <FrameLayout
        android:id="@+id/top_frame"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <View
        android:layout_width="match_parent"
        android:layout_height="12dp"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"
        android:background="#004" />

    <FrameLayout
        android:id="@+id/bottom_frame"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

</LinearLayout>

fragment_city.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/item_number"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/text_margin"
        android:textAppearance="?attr/textAppearanceListItem" />

    <TextView
        android:id="@+id/content"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/text_margin"
        android:textAppearance="?attr/textAppearanceListItem" />
</LinearLayout>

fragment_city_list.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView 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:id="@+id/list"
    android:name="com.example.myapplication.CityFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layoutManager="LinearLayoutManager"
    tools:context=".CityFragment"
    tools:listitem="@layout/fragment_city" />

fragment_content.xml:

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/description"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:textSize="20sp" />
</ScrollView>

strings.xml:

<resources>
    <string name="app_name">Tour Guide</string>
    <array name="cities">
        <item>Calgary</item>
        <item>Victoria</item>
        <item>Vancouvar</item>
        <item>Another city</item>
    </array>

    <array name="descriptions">
        <item>Description of the city Calgary</item>
        <item>Description of the city Victoria</item>
        <item>Again here would be the description</item>
        <item>Keep in mind to have same number of items in both of these arrays else app will crash</item>
    </array>
</resources>