Preparing GuestbooksActivity for Guestbook List Screenlet

Recall that you want GuestbooksActivity to display Guestbook List Screenlet and Entry List Screenlet. Before using these Screenlets, however, you must prepare GuestbooksActivity as follows:

1. Refactor the action bar so you can later set its title to the selected guestbook’s name.

2. Refactor the navigation drawer so you can later close it when a guestbook is selected in Guestbook List Screenlet.

3. Delete the NavigationView.OnNavigationItemSelectedListener implementation. Since Guestbook List Screenlet handles guestbook selections, you don’t need NavigationView.

When you finish, you’ll be ready to use Guestbook List Screenlet. Note that you won’t always have to take steps like these before using Screenlets. You only do so here to fit this particular app’s design.

First, you’ll refactor the action bar.

Refactoring the Action Bar

By default, the action bar displays the activity’s name. When you use Guestbook List Screenlet, you want the action bar to display the selected guestbook’s name instead. You’ll enable this by modifying the code that creates the action bar. Android Studio created this code for you in the GuestbooksActivity class’s onCreate method:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

1. Remove this code. Although you could edit it, you’ll instead create a separate method that creates the action bar. Note that you don’t need to worry about the now missing toolbar variable in onCreate; you’ll fix it shortly.

2. Create ActionBar and Toolbar instance variables. This lets you refer to them anywhere in the activity. Add these variables to the GuestbooksActivity class:

   Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
   setSupportActionBar(toolbar);
   

   This requires that you import android.support.v7.app.ActionBar.

3. Add the following initActionBar() method to GuestbooksActivity:

   private void initActionBar() {
       toolbar = (Toolbar) findViewById(R.id.toolbar);
       setSupportActionBar(toolbar);
       actionBar = getSupportActionBar();
       actionBar.setTitle("");
   }
   

   Like the code you removed from onCreate, this method also creates a Toolbar and sets it as the action bar. It also sets the action bar’s title to an empty string. This prevents the activity’s title from showing in the action bar before the app can retrieve guestbooks from the portlet.

4. Call initActionBar() in onCreate. Place the call immediately below the setContentView call. The first few lines of onCreate should now look like this:

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

Next, you’ll modify the code that controls the navigation drawer.

Refactoring the Navigation Drawer

Before you can use Guestbook List Screenlet in the navigation drawer, you must refactor the drawer’s existing code. Do so now by following these steps:

1. Currently, the navigation drawer initialization code is in the onCreate method. Android Studio created this code for you when you used the Navigation Drawer Activity template to create GuestbooksActivity. Delete this code from onCreate:

   DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
   ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
       this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
   drawer.setDrawerListener(toggle);
   toggle.syncState();
   

   Instead, you’ll initialize the navigation drawer in a separate method that you’ll call in onCreate. You’ll create this method shortly.

2. You’ll also change the drawer variable to be an instance variable that you can refer to throughout the class. This lets you use this variable to close the drawer when a guestbook is selected in Guestbook List Screenlet. Add this variable to GuestbooksActivity:

   private DrawerLayout drawer;
   

3. Add the following initDrawer method. This method’s contents match the drawer initialization code you deleted in onCreate, except that drawer is now an instance variable:

   private void initDrawer() {
       // drawer initialization
       drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
       ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
           this, drawer, toolbar, R.string.navigation_drawer_open, 
           R.string.navigation_drawer_close);
       drawer.setDrawerListener(toggle);
       toggle.syncState();
   }
   

4. In the onCreate method, place the call to initDrawer() immediately below the initActionBar call. The first few lines of onCreate should now look like this:

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_guestbooks);
   
       initActionBar();
       initDrawer();
   
       ...
   }
   

5. Also, because you want to use the same DrawerLayout instance throughout the class, delete the line of code that creates a new DrawerLayout in the onBackPressed method. Your onBackPressed method should now look like this:

   @Override
   public void onBackPressed() {
       if (drawer.isDrawerOpen(GravityCompat.START)) {
           drawer.closeDrawer(GravityCompat.START);
       } else {
           super.onBackPressed();
       }
   }
   

Now you’re ready to delete the NavigationView.OnNavigationItemSelectedListener implementation. The next section walks you through this.

Deleting the NavigationView.OnNavigationItemSelectedListener Implementation

Since Guestbook List Screenlet handles navigation drawer item selections, you don’t need to implement NavigationView.OnNavigationItemSelectedListener in GuestbooksActivity. Follow these steps to remove this implementation:

1. Delete the implementation from the class declaration. The class declaration should now look like this:

   public class GuestbooksActivity extends AppCompatActivity {...
   

2. Remove the code in GuestbooksActivity that implements NavigationView.OnNavigationItemSelectedListener. To do this, first delete the following code at the end of the onCreate method:

   NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
   navigationView.setNavigationItemSelectedListener(this);
   

   Your onCreate method should now look like this:

   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_guestbooks);
   
       initActionBar();
       initDrawer();
   
       FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
       fab.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View view) {
               Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                   .setAction("Action", null).show();
           }
       });
   }
   

3. Delete the onNavigationItemSelected method, along with its @Override and @SuppressWarnings("StatementWithEmptyBody") statements.

4. Finally, remove the android.support.design.widget.NavigationView import.

Great job! Now you’re ready to insert Guestbook List Screenlet in GuestbooksActivity.