ListView: plug an Adapter into an AdapterView

Select a metal to pop up a piece of Toast.

An ArrayAdapter is an example of an Adapter. A ListView is an example of an AdapterView; see List View.

There’s a special subclass of class Activity called ListActivity that automatically creates a ListView without having to call setContentView. A ListActivity also automatically listens for items being clicked on. But a ListActivity does not display a action bar, so I decided not to use it. I stuck with our customary ActionBarActivity.

onItemClick has two different ways to get the string in the item that was clicked on. I commented out one of them.

Source code in List.zip

1. MainActivity.java plugs an ArrayAdapter<String> and an AdapterView.OnItemClickListener into a ListView.
2. R.java
3. activity_main.xml: a RelativeLayout fills the screen, and a ListView fills the RelativeLayout.
4. styles.xml
5. AndroidManifest.xml
6. build.gradle (Module: app).

simple_list_item_1.xml

A line of a ListView is displayed as the TextView in the following file
~/Library/Android/sdk/platforms/android-24/data/res/layout/simple_list_item_1.xml
(shown without its copyright notice and <?xml> tag). The id number of this file is
android.R.layout.simple_list_item_1.

A question mark refers to an attribute of the current theme. See Referencing style attributes.

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceListItemSmall"
    android:gravity="center_vertical"
    android:paddingStart="?android:attr/listPreferredItemPaddingStart"
    android:paddingEnd="?android:attr/listPreferredItemPaddingEnd"
    android:minHeight="?android:attr/listPreferredItemHeightSmall"
/>

Lists in ApiDemos

1. Views → Lists → 01. Array
   500 types of cheese
   1. ApiDemos/src/com/example/android/apis/view/List1.java
      A ListActivity plugs an ArrayAdapter<String> into the ListActivity.
   2. ApiDemos/src/com/example/android/apis/view/Cheeses.java
      A class containing a static field that is an array of Strings.


2. Views → Lists → 04. ListAdapter
   A list whose items are vertical LinearLayouts
   1. ApiDemos/src/com/example/android/apis/view/List4.java
      A List4.SpeechListAdapter is a BaseAdapter that creates Views that are LinearLayouts.
   2. ApiDemos/src/com/example/android/apis/Shakespeare.java
      A class containing two static fields, TITLES and DIALOGUE, that are arrays of Strings.

Things to try

1. List all the activities in the launcher page (the page of icons). Change

           String[] a = {"copper", "iron", "steel", "Rearden Metal"};
   

   to the following. See the android.intent.action.MAIN and android.intent.category.LAUNCHER in AndroidManifest.

           Intent intent = new Intent(Intent.ACTION_MAIN, null);
           intent.addCategory(Intent.CATEGORY_LAUNCHER);
   
           PackageManager packageManager = getPackageManager();
           List<ResolveInfo> list = packageManager.queryIntentActivities(intent, 0); //0 for no flags
   
   	String[] a = new String[list.size()];
           for (int i = 0; i < list.size(); ++i) {
               ResolveInfo resolveInfo = list.get(i);
               ActivityInfo activityInfo = resolveInfo.activityInfo;
               CharSequence label = activityInfo.loadLabel(packageManager);
               a[i] = label.toString();
           }
           Arrays.sort(a);
   

   


2. Let’s track down textAppearanceListItemSmall.
   1. ~/Library/Android/sdk/platforms/android-24/data/res/values/themes_holo.xml defines textAppearanceListItemSmall to be textAppearanceMedium.
   2. ~/Library/Android/sdk/platforms/android-24/data/res/values/themes_holo.xml defines textAppearanceMedium to be TextAppearance.Holo.Medium.
   3. ~/Library/Android/sdk/platforms/android-24/data/res/values/styles_holo.xml defines TextAppearance.Holo.Medium to be TextAppearance.Medium.
   4. ~/Library/Android/sdk/platforms/android-24/data/res/values/styles.xml defines TextAppearance.Medium to be 18sp.