Make shortform demo work on TV

RELEASENOTES.md

@@ -50,6 +50,8 @@
             invalidate itself automatically. Apps don't need to call
             `invalidate()` explicitly anymore after updating the current playing
             index.
+    *   Make short-form demo work on TV with D-pad
+        ([#2720](https://github.com/androidx/media/pull/2720)).
 *   Transformer:
 *   Track Selection:
     *   Add `TrackSelectionParameters.selectTextByDefault` to prefer the

demos/shortform/src/main/AndroidManifest.xml

@@ -16,9 +16,13 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="androidx.media3.demo.shortform">
 
+  <uses-feature android:name="android.software.leanback" android:required="false"/>
+  <uses-feature android:name="android.hardware.touchscreen" android:required="false"/>
+
   <application
     android:allowBackup="false"
     android:icon="@mipmap/ic_launcher"
+    android:banner="@drawable/ic_banner"
     android:label="@string/app_name"
     android:theme="@style/Theme.MaterialComponents.DayNight.NoActionBar"
     android:taskAffinity="">
@@ -28,6 +32,7 @@
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />
+        <category android:name="android.intent.category.LEANBACK_LAUNCHER"/>
       </intent-filter>
     </activity>
     <activity

demos/shortform/src/main/java/androidx/media3/demo/shortform/viewpager/ViewPagerActivity.kt

@@ -17,6 +17,7 @@ package androidx.media3.demo.shortform.viewpager
 
 import android.os.Bundle
 import android.util.Log
+import android.view.KeyEvent
 import androidx.appcompat.app.AppCompatActivity
 import androidx.media3.demo.shortform.MainActivity
 import androidx.media3.demo.shortform.MediaItemDatabase
@@ -60,4 +61,16 @@ class ViewPagerActivity : AppCompatActivity() {
     viewPagerView.adapter = null
     super.onStop()
   }
+
+  override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean {
+    when (keyCode) {
+      KeyEvent.KEYCODE_DPAD_DOWN,
+      KeyEvent.KEYCODE_CHANNEL_UP ->
+        viewPagerView.setCurrentItem(viewPagerView.currentItem + 1, false)
+      KeyEvent.KEYCODE_DPAD_UP,
+      KeyEvent.KEYCODE_CHANNEL_DOWN ->
+        viewPagerView.setCurrentItem(viewPagerView.currentItem - 1, false)
+    }
+    return super.onKeyUp(keyCode, event)
+  }
 }