API Level：定义、API版本与targetSdk

// build.gradle.kts — API Level 配置示例
plugins {
    id("com.android.application") version "8.7.0"
    id("org.jetbrains.kotlin.android") version "2.1.0"
}

android {
    namespace = "com.example.myapp"
    compileSdk = 36  // Android 16

    defaultConfig {
        applicationId = "com.example.myapp"
        minSdk = 26      // Android 8.0
        targetSdk = 36    // Android 16
        versionCode = 1
        versionName = "1.0.0"
    }

    buildTypes {
        release {
            isMinifyEnabled = true
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }

    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_17
        targetCompatibility = JavaVersion.VERSION_17
    }

    kotlinOptions {
        jvmTarget = "17"
    }
}

dependencies {
    implementation("androidx.core:core-ktx:1.15.0")
    implementation("androidx.appcompat:appcompat:1.7.0")
    implementation("androidx.activity:activity-ktx:1.9.3")
}

// 处理 Android 13（API 33）行为变更：POST_NOTIFICATIONS
import android.Manifest
import android.content.pm.PackageManager
import android.os.Build
import androidx.activity.result.contract.ActivityResultContracts
import androidx.core.content.ContextCompat

class NotificationHelper {

    fun requestNotificationPermission(activity: MainActivity) {
        // POST_NOTIFICATIONS 权限仅适用于 API 33+
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
            return  // 低于 API 33 不需要此权限
        }

        when {
            ContextCompat.checkSelfPermission(
                activity,
                Manifest.permission.POST_NOTIFICATIONS
            ) == PackageManager.PERMISSION_GRANTED -> {
                // 权限已授予，可以发送通知
                showNotification(activity)
            }

            activity.shouldShowRequestPermissionRationale(
                Manifest.permission.POST_NOTIFICATIONS
            ) -> {
                // 显示为何需要该权限的说明
                activity.showRationale()
            }

            else -> {
                // 请求权限
                activity.requestPermissionLauncher.launch(
                    Manifest.permission.POST_NOTIFICATIONS
                )
            }
        }
    }

    private fun showNotification(context: Context) {
        // 创建并显示通知
        val notification = android.app.Notification.Builder(context, "default_channel")
            .setSmallIcon(android.R.drawable.ic_dialog_info)
            .setContentTitle("通知")
            .setContentText("新消息")
            .build()
        val manager = context.getSystemService(Context.NOTIFICATION_SERVICE)
            as android.app.NotificationManager
        manager.notify(1, notification)
    }
}

// 在 Activity 中注册 requestPermissionLauncher
class MainActivity : ComponentActivity() {
    val requestPermissionLauncher = registerForActivityResult(
        ActivityResultContracts.RequestPermission()
    ) { isGranted: Boolean ->
        if (isGranted) {
            // 权限已授予
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

// Android 代码中检查 API Level 的示例
import android.os.Build
import android.os.Build.VERSION
import android.os.Build.VERSION_CODES
import android.graphics.drawable.AdaptiveIconDrawable

class ApiLevelHelper {

    // 1. 基本 API Level 检查
    fun isAtLeastTiramisu(): Boolean {
        return VERSION.SDK_INT >= VERSION_CODES.TIRAMISU  // 33
    }

    // 2. 带检查的自适应 API 调用
    fun getAdaptiveIcon(drawable: android.graphics.drawable.Drawable):
            android.graphics.drawable.Drawable? {
        // AdaptiveIconDrawable 仅适用于 API 26（Android 8）
        if (VERSION.SDK_INT >= VERSION_CODES.O) {
            return AdaptiveIconDrawable(drawable, null)
        }
        return drawable  // 针对旧设备的 fallback
    }

    // 3. 检查 POST_NOTIFICATIONS 权限（仅限 API 33+）
    fun canRequestNotificationPermission(): Boolean {
        return VERSION.SDK_INT >= VERSION_CODES.TIRAMISU
    }

    // 4. 根据 API Level 选择图片提供器
    fun getImagePickerProvider(): String {
        return when {
            VERSION.SDK_INT >= VERSION_CODES.UPSIDE_DOWN_CAKE -> {
                // API 34+ 使用 PhotoPicker
                "photo_picker"
            }
            VERSION.SDK_INT >= VERSION_CODES.KITKAT -> {
                // API 19+ 使用 Intent ACTION_OPEN_DOCUMENT
                "open_document"
            }
            else -> {
                // Legacy：ACTION_GET_CONTENT（所有版本）
                "get_content"
            }
        }
    }

    // 5. 通过 @TargetApi 进行 Java 风格的检查（用于向后兼容性）
    @Suppress("DEPRECATION")
    fun checkLegacyStorage(): Boolean {
        // Scoped Storage 的行为取决于 targetSdk，而非 SDK_INT
        return VERSION.SDK_INT < VERSION_CODES.Q  // Android 10
    }

    // 6. 用于分析的构建信息
    fun getDeviceApiInfo(): Map<String, Any> {
        return mapOf(
            "sdk_int" to VERSION.SDK_INT,
            "release" to VERSION.RELEASE,
            "codename" to VERSION.CODENAME,
            "incremental" to VERSION.INCREMENTAL,
            "preview_sdk" to VERSION.PREVIEW_SDK_INT
        )
    }
}

// 测试
fun main() {
    val helper = ApiLevelHelper()
    println("API Level: ${VERSION.SDK_INT}")
    println("Is Tiramisu+: ${helper.isAtLeastTiramisu()}")
}