diff --git a/app/src/main/java/top/yeij/hearth/app/AppRepository.kt b/app/src/main/java/top/yeij/hearth/app/AppRepository.kt
new file mode 100644
index 0000000..ed72f6b
--- /dev/null
+++ b/app/src/main/java/top/yeij/hearth/app/AppRepository.kt
@@ -0,0 +1,41 @@
+package top.yeij.hearth.app
+
+import android.content.Context
+import android.content.Intent
+import android.util.Log
+
+data class AppInfo(val packageName: String, val label: String, val iconBase64: String?)
+
+interface AppSource {
+    fun queryLaunchableApps(): List<AppInfo>
+    fun launch(packageName: String): Boolean
+}
+
+class AndroidAppSource(private val context: Context) : AppSource {
+    override fun queryLaunchableApps(): List<AppInfo> {
+        val pm = context.packageManager
+        val intent = Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER)
+        return pm.queryIntentActivities(intent, 0).map { ri ->
+            val pkg = ri.activityInfo.packageName
+            AppInfo(pkg, ri.loadLabel(pm).toString(), null /* 图标 base64 在 Task 5 补 */)
+        }
+    }
+
+    override fun launch(packageName: String): Boolean {
+        val i = context.packageManager.getLaunchIntentForPackage(packageName) ?: return false
+        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+        context.startActivity(i)
+        return true
+    }
+}
+
+class AppRepository(private val source: AppSource) {
+    private val gson = com.google.gson.Gson()
+
+    fun listApps(): String {
+        Log.d("HearthBridge", "listApps: ${source.queryLaunchableApps().size} apps")
+        return gson.toJson(source.queryLaunchableApps())
+    }
+
+    fun launchApp(packageName: String): Boolean = source.launch(packageName)
+}
diff --git a/app/src/test/java/top/yeij/hearth/app/AppRepositoryTest.kt b/app/src/test/java/top/yeij/hearth/app/AppRepositoryTest.kt
new file mode 100644
index 0000000..c559898
--- /dev/null
+++ b/app/src/test/java/top/yeij/hearth/app/AppRepositoryTest.kt
@@ -0,0 +1,21 @@
+package top.yeij.hearth.app
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class AppRepositoryTest {
+    @Test
+    fun listApps_returnsLauncherAppsJson() {
+        val repo = AppRepository(FakeAppSource(listOf(FakeApp("com.x.music", "音乐"))))
+        val json = repo.listApps()
+        assertTrue(json.contains("\"packageName\":\"com.x.music\""))
+        assertTrue(json.contains("\"label\":\"音乐\""))
+    }
+
+    @Test
+    fun launchApp_unknownPackage_returnsFalse() {
+        val repo = AppRepository(FakeAppSource(emptyList()))
+        assertEquals(false, repo.launchApp("com.nope"))
+    }
+}
diff --git a/app/src/test/java/top/yeij/hearth/app/TestFakes.kt b/app/src/test/java/top/yeij/hearth/app/TestFakes.kt
new file mode 100644
index 0000000..4205dd3
--- /dev/null
+++ b/app/src/test/java/top/yeij/hearth/app/TestFakes.kt
@@ -0,0 +1,13 @@
+package top.yeij.hearth.app
+
+// 测试用假源：返回固定应用列表，避免依赖 Android Context/PackageManager
+// Test fake source: returns a fixed app list, avoiding dependency on Android Context/PackageManager
+class FakeAppSource(private val apps: List<AppInfo>) : AppSource {
+    override fun queryLaunchableApps(): List<AppInfo> = apps
+
+    override fun launch(packageName: String): Boolean = apps.any { it.packageName == packageName }
+}
+
+// 测试用 AppInfo 构造辅助函数
+// Test helper to construct an AppInfo
+fun FakeApp(packageName: String, label: String): AppInfo = AppInfo(packageName, label, null)