Android各版本兼容性适配详解

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <!-- 内部存储，对应 filesDir，路径：/data/data/package_name/files-->
    <files-path
        name="files_path"
        path="." />
    <!-- 内部存储，对应 cacheDir，路径：/data/data/package_name/cache-->
    <cache-path
        name="cache_path"
        path="." />
    <!--外部存储，对应 getExternalFilesDir，路径：/storage/sdcard/Android/data/package_name/files-->
    <external-files-path
        name="external_files_path"
        path="." />
    <!--外部存储，对应 externalCacheDir，路径：/storage/sdcard/Android/data/package_name/cache-->
    <external-cache-path
        name="external_cache_path"
        path="." />
</paths>

<provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="com.example.myapplication.fileProvider"
    android:exported="false"
    android:grantUriPermissions="true">
    <!--exported 要为 false，否则会报安全异常，grantUriPermissions 为 true，表示授予 URI 临时访问权限-->
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

val pictureFile =
    File(getExternalFilesDir(null), "${System.currentTimeMillis()}.jpg")
if (!pictureFile.exists()) {
    pictureFile.createNewFile()
}
val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    // 通过 FileProvider 创建一个 content 类型的 Uri
    val pictureUri =
        FileProvider.getUriForFile(
            this,
            "com.example.myapplication.fileProvider",
            pictureFile
        )
    intent.putExtra(MediaStore.EXTRA_OUTPUT, pictureUri)
    // 授予目录临时共享权限
    intent.flags = Intent.FLAG_GRANT_WRITE_URI_PERMISSION
    startActivity(intent)
} else {
    val pictureUri = Uri.fromFile(pictureFile)
    intent.putExtra(MediaStore.EXTRA_OUTPUT, pictureUri)
    startActivity(intent)
}

val notificationManager =
    getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    val notificationChannel = NotificationChannel(
        "Channel_ID",
        "Channel_Name",
        NotificationManager.IMPORTANCE_DEFAULT
    )
    notificationManager.createNotificationChannel(notificationChannel)
    val notification =
        NotificationCompat.Builder(this, "Channel_ID")
            .setSmallIcon(R.drawable.ic_launcher_background)
            .setContentTitle("title").setContentText("content").build()
    notificationManager.notify(1, notification)
} else {
    val notification =
        NotificationCompat.Builder(this).setSmallIcon(R.drawable.ic_launcher_background)
            .setContentTitle("title").setContentText("content").build()
    notificationManager.notify(1, notification)
}

<uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>

val intent = Intent(this, MyService::class.java)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    startForegroundService(intent)
} else {
    startService(intent)
}

class MyService : Service() {
    override fun onBind(intent: Intent): IBinder? = null
    override fun onCreate() {
        super.onCreate()
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val manager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
            val channel = NotificationChannel(
                "Channel_ID", "Channel_Name", NotificationManager.IMPORTANCE_DEFAULT
            )
            manager.createNotificationChannel(channel)
            val notification = Notification.Builder(this, "Channel_ID").build()
            startForeground(1, notification)
        }
    }
    override fun onDestroy() {
        super.onDestroy()
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            stopForeground(true)
        }
    }
}

<application
    ...
    android:usesCleartextTraffic="true">
    ...
</application>

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">www.wanandroid.com</domain>
    </domain-config>
</network-security-config>

<application
    ...
    android:networkSecurityConfig="@xml/network_config">
    ...
</application>

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

PermissionX.init(this)
    .permissions(Manifest.permission.READ_EXTERNAL_STORAGE).request { allGranted, _, _ ->
        if (allGranted) {
            Log.i(tag, "All permissions have been agreed")
        } else {
            Toast.makeText(this, "Please agree to the permission", Toast.LENGTH_SHORT)
                .show()
        }
    }

val uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI
val cursor = contentResolver.query(uri, null, null, null, null)
cursor?.let {
    val indexPhotoPath = it.getColumnIndexOrThrow(MediaStore.Images.Media.DATA)
    while (it.moveToNext()) {
        Log.i(tag, "picture path: ${it.getString(indexPhotoPath)}")
    }
    it.close()
}

private lateinit var startActivity: ActivityResultLauncher<Intent>

startActivity =
    registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
        if (it.data != null && it.resultCode == Activity.RESULT_OK) {
            readFileContent(it.data!!.data)
        }
    }

private fun writeForUri(uri: Uri?) {
    if (uri == null) return
    try {
        val outputStream = contentResolver.openOutputStream(uri)
        val content = "Hello Android"
        outputStream?.write(content.toByteArray())
        outputStream?.flush()
        outputStream?.close()
    } catch (e: Exception) {
        e.printStackTrace()
    }
}

private fun readFileContent(uri: Uri?) {
    if (uri == null) return
    try {
        val inputStream = contentResolver.openInputStream(uri) ?: return
        val readContent = ByteArray(1024)
        var len: Int
        do {
            len = inputStream.read(readContent)
            if (len != -1) { //打印出文件内容
                Log.d(tag, "File Content: ${String(readContent).substring(0, len)}")
            }
        } while (len != -1)
        inputStream.close()
    } catch (e: Exception) {
        e.printStackTrace()
    }
}

    private fun openSAF() {
        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
        intent.addCategory(Intent.CATEGORY_OPENABLE)
        //指定选择文本类型的文件
        intent.type = "text/plain"
        startActivity.launch(intent)
    }

val appList = packageManager.getInstalledApplications(PackageManager.GET_META_DATA)
for (app in appList) {
    Log.i(tag, "packageName: ${app.packageName}")
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    ...
    <queries>
        <package android:name="com.example.composeapp" />
    </queries>
    ...
</manifest>

implementation 'androidx.core:core-splashscreen:1.0.0'

<style name="Theme.App.Splash" parent="Theme.SplashScreen">
    <!--特定的单色填充背景-->
    <item name="windowSplashScreenBackground">@color/white</item>
    <!--起始窗口中心的图标-->
    <item name="windowSplashScreenAnimatedIcon">@drawable/splash_icon</item>
    <!--启动画面图标动画的时长，Google 建议不超过 1000 毫秒-->
    <item name="windowSplashScreenAnimationDuration">200</item>
    <!--必填项，SplashView 移除后使用此主题恢复 Activity 样式-->
    <item name="postSplashScreenTheme">@style/Theme.MyApplication</item>
</style>

<application
    ...
    android:theme="@style/Theme.App.Splash">
    ...
</application>

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