Improve null safety for app pairs

- Improves crash safety in AppPairIcon.java. An app pair should never have more or fewer than 2 app members, but if it happens somehow and there is an app pair on the home screen, the device will enter a crash loop that is hard to recover from. Added some safety checks so that it doesn't happen.

Fixes: 317283244
Test: Manual and presubmit tested
Flag: ACONFIG com.android.wm.shell.enable_app_pairs TEAMFOOD
Change-Id: I2cbd90f028f7c31af6e832b5515502ba992f0b54
diff --git a/src/com/android/launcher3/apppairs/AppPairIconGraphic.kt b/src/com/android/launcher3/apppairs/AppPairIconGraphic.kt
index 2945979..fa840ed 100644
--- a/src/com/android/launcher3/apppairs/AppPairIconGraphic.kt
+++ b/src/com/android/launcher3/apppairs/AppPairIconGraphic.kt
@@ -21,9 +21,11 @@
 import android.graphics.Rect
 import android.graphics.drawable.Drawable
 import android.util.AttributeSet
+import android.util.Log
 import android.view.Gravity
 import android.widget.FrameLayout
 import com.android.launcher3.DeviceProfile
+import com.android.launcher3.model.data.WorkspaceItemInfo
 
 /**
  * A FrameLayout marking the area on an [AppPairIcon] where the visual icon will be drawn. One of
@@ -31,6 +33,8 @@
  */
 class AppPairIconGraphic @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null) :
     FrameLayout(context, attrs) {
+    private val TAG = "AppPairIconGraphic"
+
     companion object {
         // Design specs -- the below ratios are in relation to the size of a standard app icon.
         private const val OUTER_PADDING_SCALE = 1 / 30f
@@ -61,8 +65,8 @@
 
     private lateinit var parentIcon: AppPairIcon
     private lateinit var appPairBackground: Drawable
-    private lateinit var appIcon1: Drawable
-    private lateinit var appIcon2: Drawable
+    private var appIcon1: Drawable? = null
+    private var appIcon2: Drawable? = null
 
     fun init(grid: DeviceProfile, icon: AppPairIcon) {
         // Calculate device-specific measurements
@@ -79,12 +83,24 @@
 
         appPairBackground = AppPairIconBackground(context, this)
         appPairBackground.setBounds(0, 0, backgroundSize.toInt(), backgroundSize.toInt())
+        applyIcons(parentIcon.info.contents)
+    }
+
+    /** Sets up app pair member icons for drawing. */
+    private fun applyIcons(contents: ArrayList<WorkspaceItemInfo>) {
+        // App pair should always contain 2 members; if not 2, return to avoid a crash loop
+        if (contents.size != 2) {
+            Log.w(TAG, "AppPair contents not 2, size: " + contents.size, Throwable())
+            return
+        }
+
         appIcon1 = parentIcon.info.contents[0].newIcon(context)
         appIcon2 = parentIcon.info.contents[1].newIcon(context)
-        appIcon1.setBounds(0, 0, memberIconSize.toInt(), memberIconSize.toInt())
-        appIcon2.setBounds(0, 0, memberIconSize.toInt(), memberIconSize.toInt())
+        appIcon1?.setBounds(0, 0, memberIconSize.toInt(), memberIconSize.toInt())
+        appIcon2?.setBounds(0, 0, memberIconSize.toInt(), memberIconSize.toInt())
     }
 
+
     /** Gets this icon graphic's bounds, with respect to the parent icon's coordinate system. */
     fun getIconBounds(outBounds: Rect) {
         outBounds.set(0, 0, backgroundSize.toInt(), backgroundSize.toInt())
@@ -118,7 +134,7 @@
         } else {
             canvas.translate(width / 2f - memberIconSize / 2f, innerPadding)
         }
-        appIcon1.draw(canvas)
+        appIcon1?.draw(canvas)
         canvas.restore()
 
         // Draw second icon
@@ -135,7 +151,7 @@
                 height - (innerPadding + memberIconSize)
             )
         }
-        appIcon2.draw(canvas)
+        appIcon2?.draw(canvas)
         canvas.restore()
     }
 }