Override for testing when clock is not set

Bug: 259097187
Test: Manually verified default clock was correctly used
Change-Id: I4fe2572aa95edf34cb7e6a4745e7dda35776c8f0

packages/SystemUI/res/values/strings.xml

@@ -1932,6 +1932,9 @@
     <!-- SysUI Tuner: Summary of no shortcut being selected [CHAR LIMIT=60] -->
     <string name="lockscreen_none">None</string>
 
+    <!-- ClockId to use when none is set by user -->
+    <string name="lockscreen_clock_id_fallback" translatable="false">DEFAULT</string>
+
     <!-- SysUI Tuner: Format string for describing launching an app [CHAR LIMIT=60] -->
     <string name="tuner_launch_app">Launch <xliff:g id="app" example="Settings">%1$s</xliff:g></string>
 

packages/SystemUI/shared/src/com/android/systemui/shared/clocks/ClockRegistry.kt

@@ -41,6 +41,7 @@ open class ClockRegistry(
     val isEnabled: Boolean,
     userHandle: Int,
     defaultClockProvider: ClockProvider,
+    val fallbackClockId: ClockId = DEFAULT_CLOCK_ID,
 ) {
     // Usually this would be a typealias, but a SAM provides better java interop
     fun interface ClockChangeListener {
@@ -69,10 +70,13 @@ open class ClockRegistry(
                     context.contentResolver,
                     Settings.Secure.LOCK_SCREEN_CUSTOM_CLOCK_FACE
                 )
-                ClockSetting.deserialize(json)?.clockId ?: DEFAULT_CLOCK_ID
+                if (json == null || json.isEmpty()) {
+                    return fallbackClockId
+                }
+                ClockSetting.deserialize(json).clockId
             } catch (ex: Exception) {
                 Log.e(TAG, "Failed to parse clock setting", ex)
-                DEFAULT_CLOCK_ID
+                fallbackClockId
             }
         }
         set(value) {

packages/SystemUI/src/com/android/keyguard/dagger/ClockRegistryModule.java

@@ -20,6 +20,7 @@ import android.content.Context;
 import android.os.Handler;
 import android.os.UserHandle;
 
+import com.android.systemui.R;
 import com.android.systemui.dagger.SysUISingleton;
 import com.android.systemui.dagger.qualifiers.Application;
 import com.android.systemui.dagger.qualifiers.Main;
@@ -50,6 +51,7 @@ public abstract class ClockRegistryModule {
                 handler,
                 featureFlags.isEnabled(Flags.LOCKSCREEN_CUSTOM_CLOCKS),
                 UserHandle.USER_ALL,
-                defaultClockProvider);
+                defaultClockProvider,
+                context.getString(R.string.lockscreen_clock_id_fallback));
     }
 }