Add GradientColorWallpaper in SystemUi

GradientColorWallpaper is a very sample wallpaper that draws a full screen rectangle.

Test: GradientColorWallpaperTest
Flag: android.app.enable_connected_displays_wallpaper
Bug: 384519696
Change-Id: Ie098a47451a3e8a6c05ef9626337212214cbca91

4 files changed, 154 insertions, 0 deletions

diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index c3c5e874b907..a935aacacf95 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -423,6 +423,7 @@ android_library {
     ],
     manifest: "AndroidManifest-res.xml",
     flags_packages: [
+        "android.app.flags-aconfig",
         "com_android_systemui_flags",
     ],
 }
diff --git a/packages/SystemUI/AndroidManifest.xml b/packages/SystemUI/AndroidManifest.xml
index 51ea5298fbb8..0075f85af8ed 100644
--- a/packages/SystemUI/AndroidManifest.xml
+++ b/packages/SystemUI/AndroidManifest.xml
@@ -547,6 +547,12 @@
                 android:permission="android.permission.BIND_WALLPAPER"
                 android:exported="true" />
 
+        <service android:name=".wallpapers.GradientColorWallpaper"
+            android:featureFlag="android.app.enable_connected_displays_wallpaper"
+            android:singleUser="true"
+            android:permission="android.permission.BIND_WALLPAPER"
+            android:exported="true" />
+
         <activity android:name=".tuner.TunerActivity"
                   android:enabled="false"
                   android:icon="@drawable/tuner"
diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/wallpapers/GradientColorWallpaperTest.kt b/packages/SystemUI/multivalentTests/src/com/android/systemui/wallpapers/GradientColorWallpaperTest.kt
new file mode 100644
index 000000000000..ba6ea9f5e8bb
--- /dev/null
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/wallpapers/GradientColorWallpaperTest.kt
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.wallpapers
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.graphics.Rect
+import android.graphics.RectF
+import android.service.wallpaper.WallpaperService.Engine
+import android.testing.TestableLooper.RunWithLooper
+import android.view.Surface
+import android.view.SurfaceHolder
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentMatchers.anyInt
+import org.mockito.Mock
+import org.mockito.Mockito.spy
+import org.mockito.MockitoAnnotations
+import org.mockito.kotlin.any
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.whenever
+
+@SmallTest
+@RunWith(AndroidJUnit4::class)
+@RunWithLooper
+class GradientColorWallpaperTest : SysuiTestCase() {
+
+    @Mock private lateinit var surfaceHolder: SurfaceHolder
+
+    @Mock private lateinit var surface: Surface
+
+    @Mock private lateinit var canvas: Canvas
+
+    @Mock private lateinit var mockContext: Context
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+
+        whenever(surfaceHolder.surface).thenReturn(surface)
+        whenever(surfaceHolder.surfaceFrame).thenReturn(surfaceFrame)
+        whenever(surface.lockHardwareCanvas()).thenReturn(canvas)
+        whenever(mockContext.getColor(anyInt())).thenReturn(1)
+    }
+
+    private fun createGradientColorWallpaperEngine(): Engine {
+        val gradientColorWallpaper = GradientColorWallpaper()
+        val engine = spy(gradientColorWallpaper.onCreateEngine())
+        whenever(engine.displayContext).thenReturn(mockContext)
+        return engine
+    }
+
+    @Test
+    fun onSurfaceRedrawNeeded_shouldDrawInCanvas() {
+        val engine = createGradientColorWallpaperEngine()
+        engine.onCreate(surfaceHolder)
+
+        engine.onSurfaceRedrawNeeded(surfaceHolder)
+
+        verify(canvas).drawRect(any<RectF>(), any<Paint>())
+    }
+
+    private companion object {
+        val surfaceFrame = Rect(0, 0, 100, 100)
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/wallpapers/GradientColorWallpaper.kt b/packages/SystemUI/src/com/android/systemui/wallpapers/GradientColorWallpaper.kt
new file mode 100644
index 000000000000..c1fb0e80cafc
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/wallpapers/GradientColorWallpaper.kt
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.wallpapers
+
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.service.wallpaper.WallpaperService
+import android.util.Log
+import android.view.SurfaceHolder
+import androidx.core.graphics.toRectF
+
+/** A wallpaper that shows a static gradient color image wallpaper. */
+class GradientColorWallpaper : WallpaperService() {
+
+    override fun onCreateEngine(): Engine = GradientColorWallpaperEngine()
+
+    inner class GradientColorWallpaperEngine : Engine() {
+        init {
+            setShowForAllUsers(true)
+        }
+
+        override fun onSurfaceRedrawNeeded(surfaceHolder: SurfaceHolder) {
+            drawFrameInternal(surfaceHolder)
+        }
+
+        private fun drawFrameInternal(surfaceHolder: SurfaceHolder) {
+            val context = displayContext ?: return
+            val surface = surfaceHolder.surface
+            var canvas: Canvas? = null
+            try {
+                canvas = surface.lockHardwareCanvas()
+                val destRectF = surfaceHolder.surfaceFrame.toRectF()
+                val toColor = context.getColor(com.android.internal.R.color.materialColorPrimary)
+
+                // TODO(b/384519696): Draw the actual gradient color wallpaper instead.
+                canvas.drawRect(destRectF, Paint().apply { color = toColor })
+            } catch (exception: IllegalStateException) {
+                Log.d(TAG, "Fail to draw in the canvas", exception)
+            } finally {
+                canvas?.let { surface.unlockCanvasAndPost(it) }
+            }
+        }
+    }
+
+    private companion object {
+        const val TAG = "GradientColorWallpaper"
+    }
+}