android - 为什么安卓:requestLegacyExternalStorage ="true" not working in Android 10 - API 29

Question

我已将我的项目 compileSdkVersion 从 28 迁移到 29，并在我的 list 中添加 android:requestLegacyExternalStorage="true"，但是像下载和文件打开这样的文件操作无法像在 SDK 28 中那样工作

gradle file

compileSdkVersion 29

defaultConfig {
    applicationId "in.example.app"
    minSdkVersion 21
    targetSdkVersion 29
    versionCode 90
    versionName "1.8.3"

    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}

Manifest file

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="in.example.app">

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.SMS_FINANCIAL_TRANSACTIONS" />

<application
    android:name=".MyApp"
    android:allowBackup="true"
    android:hardwareAccelerated="true"
    android:icon="@mipmap/ic_launcher"
    android:largeHeap="true"
    android:networkSecurityConfig="@xml/network_security_config"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    tools:replace="android:theme,android:allowBackup"
    tools:targetApi="n"
    android:requestLegacyExternalStorage="true">

    <activity android:name=".ui.main.MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>

    <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="in.example.app.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/provider_paths" />
    </provider>

</application>

file downloading code

fun startDownloading(path: String, url: String): Long {
    return try {
        val downFileName = re.replace(url.substringAfterLast("/"), "")

        val downloadManager = context.getSystemService(DOWNLOAD_SERVICE) as DownloadManager
        val request = DownloadManager.Request(Uri.parse(url))
            request.setTitle(downFileName)
                .setDestinationInExternalPublicDir(path, downFileName)
                .setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
        downloadManager.enqueue(request)
    } catch (e: Exception){
        0
    }
}

路径应该是内部存储“/myapp/study materials/”中的文件夹位置

url 应该是来自服务器的文件位置 url

opening a file

fun openFile(title: String, path: String){
    try {
        val newFile = File(Environment.getExternalStorageDirectory().absolutePath + path, title)

        val uri = if (Build.VERSION.SDK_INT > Build.VERSION_CODES.M)
        {
            FileProvider.getUriForFile(context, BuildConfig.APPLICATION_ID + ".fileprovider", newFile)
        } else{
            Uri.fromFile(newFile)
        }

        val intent = Intent(Intent.ACTION_VIEW, uri)
        intent.setDataAndType(uri, context.contentResolver.getType(uri))
        intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TOP
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
        val activities: List<ResolveInfo> = context.packageManager.queryIntentActivities(intent, 0)
        val isIntentSafe: Boolean = activities.isNotEmpty()

        // Start an activity if it's safe
        if (isIntentSafe) {
            context.startActivity(Intent.createChooser(intent, "Open With"))
        } else{
            MDToast.makeText(context, "No Application Found For Opening This File", MDToast.TYPE_INFO).show()
        }
    } catch (e : Exception){
        println("=============== ${e.message}")
    }

}

路径应该是内部存储“/myapp/study materials/”中的文件夹位置

标题应该是文件名

file existance checking

override fun checkFileExistence(title: String, path: String): Boolean {
    var flag = false
    try {
        val direct = File(
            Environment.getExternalStorageDirectory().toString()
                    + path + title)
        flag = direct.exists()
    } catch (e: Exception) {
    }

    return flag
}

路径应该是内部存储“/myapp/study materials/”中的文件夹位置

标题应该是文件名

我添加了所有在更新到 SDK 29 时不起作用的代码，我想从服务器下载文件并将其保存到内部存储中的应用程序特定文件夹中还需要在下载之前检查文件是否已经下载它。如果已经下载，我需要打开该文件

Answer 1

我有与这里提到的类似的问题。我发现在 Android 10 上，我必须检查 WRITE_EXTERNAL_STORAGE即使文件已经下载，我只需要打开它。

if (ContextCompat.checkSelfPermission(this, WRITE_EXTERNAL_STORAGE) != PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, arrayOf(WRITE_EXTERNAL_STORAGE), 100)
}

在对文件进行任何操作之前添加检查修复了打开 APK 文件时“解析包时出现问题”错误。
编辑:
我还找到了另一个(可能更好)的解决方案。我没有使用外部公共(public)存储，而是切换到应用程序的外部存储:

downloadRequest.setDestinationInExternalFilesDir(...)

并访问文件使用

new File(context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), mFileName);

而不是 now deprecated Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)作为奖励，无需使用 android:requestLegacyExternalStorage="true"在 AndroidManifest 中。