2025 中階 Android 開發者職涯規劃與面試問題

摘要

本文針對2025年中階Android開發者的職涯規劃提供深入見解，幫助讀者掌握未來技術趨勢及面試準備技巧。 歸納要點:

• 深入剖析 Jetpack Compose 的效能優化策略,涵蓋布局性能調校、動畫優化及跨平台應用案例。
• 探討 Clean Architecture 如何與現代測試策略結合,並提供各種測試框架的進階用法與設計可測試程式碼的技巧。
• 分析 Kotlin Coroutines 的高階應用,包括結構化併發和異常處理,以及如何將其有效整合至大型專案中。

Android 中階開發者養成之路：精通 Kotlin、Jetpack Compose 與 Clean Architecture

Android 工程師面試：協程、Jetpack 與測試技巧全攻略

data class Node(var value: Int, var next: Node? = null)  fun reverseLinkedList(head: Node?): Node? {     var current = head     var prev: Node? = null     var next: Node?      while (current != null) {         next = current.next         current.next = prev         prev = current         current = next     }     return prev }  // Example usage val head = Node(1, Node(2, Node(3, Node(4, null)))) val reversedHead = reverseLinkedList(head)

suspend fun fetchApiData() {     coroutineScope {         val api1 = async { fetchFromApi1() }         val api2 = async { fetchFromApi2() }          val result1 = api1.await()         val result2 = api2.await()         println("Result 1: $result1, Result 2: $result2")     } }  suspend fun fetchFromApi1(): String {     delay(1000) // Simulate network delay     return "Data from API 1" }  suspend fun fetchFromApi2(): String {     delay(1500) // Simulate network delay     return "Data from API 2" }

@Composable fun ClickableList(items: List, onClick: (String) -> Unit) {     LazyColumn {         items(items) { item ->             Text(                 text = item,                 modifier = Modifier                     .fillMaxWidth()                     .padding(16.dp)                     .clickable { onClick(item) }             )         }     } }  // Example usage @Preview @Composable fun PreviewClickableList() {     val sampleItems = listOf("Item 1", "Item 2", "Item 3")     ClickableList(sampleItems) { clickedItem ->         println("Clicked on: $clickedItem")     } }

inline fun calculate(a: Int, b: Int, operation: (Int, Int) -> Int): Int {     return operation(a, b) }  // Usage val sum = calculate(5, 10) { x, y -> x + y }

@Dao interface UserDao {     @Query("SELECT * FROM users WHERE age > :minAge")     suspend fun getUsersAboveAge(minAge: Int): List }  // Usage val users = userDao.getUsersAboveAge(25)

@HiltViewModel class MyViewModel @Inject constructor(     private val repository: MyRepository ) : ViewModel() {     val data = repository.getData() }  // In Fragment @AndroidEntryPoint class MyFragment : Fragment() {     private val viewModel: MyViewModel by viewModels() }

class MyViewModel : ViewModel() {     private val _uiState = MutableStateFlow("Initial State")     val uiState: StateFlow get() = _uiState      fun fetchData() {         _uiState.value = "Loading..."         viewModelScope.launch {             delay(1000) // Simulate network call             _uiState.value = "Data loaded!"         }     } }

@Composable fun MyScreen(viewModel: MyViewModel = hiltViewModel()) {     val uiState by viewModel.uiState.collectAsState()      when (uiState) {         "Loading..." -> CircularProgressIndicator()         "Data loaded!" -> Text(text = uiState)         else -> Text(text = uiState)     } }

class SharedViewModel : ViewModel() {     private val _sharedData = MutableStateFlow("Default Value")     val sharedData: StateFlow get() = _sharedData      fun updateSharedData(data: String) {         _sharedData.value = data     } }  // Fragment A class FragmentA : Fragment() {     private val viewModel: SharedViewModel by activityViewModels()      override fun onViewCreated(view: View, savedInstanceState: Bundle?) {         viewModel.updateSharedData("Hello from Fragment A")     } }  // Fragment B class FragmentB : Fragment() {     private val viewModel: SharedViewModel by activityViewModels()      override fun onViewCreated(view: View, savedInstanceState: Bundle?) {         lifecycleScope.launchWhenStarted {             viewModel.sharedData.collect { data ->                 println("Received in Fragment B: $data")             }         }     } }

class MyViewModel : ViewModel() {     private val _events = MutableSharedFlow()     val events: SharedFlow get() = _events      fun sendEvent(message: String) {         viewModelScope.launch {             _events.emit(message) // Emit a one-time event         }     } }  // In Compose @Composable fun EventScreen(viewModel: MyViewModel = hiltViewModel()) {     val context = LocalContext.current      LaunchedEffect(Unit) {         viewModel.events.collect { event ->             Toast.makeText(context, event, Toast.LENGTH_SHORT).show()         }     } }

fun coldFlowExample(): Flow = flow {     println("Flow started") // Called only when collected     emit(1)     emit(2)     emit(3) }  // Usage: lifecycleScope.launch {     coldFlowExample().collect { value ->         println("Collected: $value")     } }

Flow started   Collected: 1   Collected: 2   Collected: 3  

class MyViewModel : ViewModel() {     private val _stateFlow = MutableStateFlow(0)     val stateFlow: StateFlow get() = _stateFlow      fun incrementCounter() {         _stateFlow.value += 1 // Emits regardless of collectors     } }  // Usage: @Composable fun HotFlowScreen(viewModel: MyViewModel = hiltViewModel()) {     val counter by viewModel.stateFlow.collectAsState()      Column {         Text(text = "Counter: $counter")         Button(onClick = { viewModel.incrementCounter() }) {             Text(text = "Increment")         }     } }

2025 Android 工程師必備：冷熱流處理、Kotlin 實戰與求職攻略