targetSdkVersion 低于 22 的下载管理器的安全异常

Question

我在Lollipop 及以下发生了奇怪的崩溃。尝试从服务器下载文件时出现安全异常，但在运行Marshmallow 及更高版本的设备中，应用程序不会崩溃。 Logcat：

原因：java.lang.SecurityException：需要 WRITE_EXTERNAL_STORAGE 权限才能使用 DESTINATION_FILE_URI：uid 10229 没有 android.permission.WRITE_EXTERNAL_STORAGE。

在App的grandle我用

 targetSdkVersion 22

在我们第一次推送 Google Console 以针对最新的 sdk 版本后会发生变化，但目前这将保持为 22，因此不需要运行时权限。 此外，我们在 App 的 Manifest 中声明了应用的权限。

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.DOWNLOAD_WITHOUT_NOTIFICATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

另外，使用DownloadManagerinside AsynckTask 的代码：

try {
        String dirPath = String.format("%5$s/%1$s/Resources/%2$s/%3$s/%4$s/", userID, resource.getiD(), filePackage.getiD(), language, dir.getCanonicalPath());
        File makeDirs = new File(dirPath);
        makeDirs.mkdirs();
    } catch (Exception ex) {
        ex.printStackTrace();
}

this.downloadManager = (DownloadManager) getApplicationContext().getSystemService(DOWNLOAD_SERVICE);
DownloadManager.Request request = new DownloadManager.Request(url);
        request.setDestinationInExternalFilesDir(getApplicationContext(), null, filePath);
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_HIDDEN);
        request.setVisibleInDownloadsUi(false);
        downloadID = downloadManager.enqueue(request);

同样，仅在操作系统版本为 5.0.2 的 Galaxy A5、运行带有Lollipop 的三星 Galaxy S6 的模拟器和运行 Kitkat 4.4.4 HTC One 的模拟器中观察到此崩溃。

完整的stack trace：

    java.lang.RuntimeException: Unable to start activity ComponentInfo{...players.PDFViewer}: java.lang.SecurityException: need WRITE_EXTERNAL_STORAGE permission to use DESTINATION_FILE_URI: uid 10229 does not have android.permission.WRITE_EXTERNAL_STORAGE.
                                                                             at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2808)
                                                                             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2873)
                                                                             at android.app.ActivityThread.access$900(ActivityThread.java:181)
                                                                             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1482)
                                                                             at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                             at android.os.Looper.loop(Looper.java:145)
                                                                             at android.app.ActivityThread.main(ActivityThread.java:6145)
                                                                             at java.lang.reflect.Method.invoke(Native Method)
                                                                             at java.lang.reflect.Method.invoke(Method.java:372)
                                                                             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
                                                                             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
                                                                          Caused by: java.lang.SecurityException: need WRITE_EXTERNAL_STORAGE permission to use DESTINATION_FILE_URI: uid 10229 does not have android.permission.WRITE_EXTERNAL_STORAGE.
                                                                             at android.os.Parcel.readException(Parcel.java:1540)
                                                                             at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:185)
                                                                             at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:137)
                                                                             at android.content.ContentProviderProxy.insert(ContentProviderNative.java:475)
                                                                             at android.content.ContentResolver.insert(ContentResolver.java:1260)
                                                                             at android.app.DownloadManager.enqueue(DownloadManager.java:1336)
                                                                             at de.imsystems.crmmobile.players.PDFViewer.onCreate(PDFViewer.java:104)
                                                                             at android.app.Activity.performCreate(Activity.java:6374)
                                                                             at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
                                                                             at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2752)
                                                                             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2873) 
                                                                             at android.app.ActivityThread.access$900(ActivityThread.java:181) 
                                                                             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1482) 
                                                                             at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                             at android.os.Looper.loop(Looper.java:145) 
                                                                             at android.app.ActivityThread.main(ActivityThread.java:6145) 
                                                                             at java.lang.reflect.Method.invoke(Native Method) 
                                                                             at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399) 
                                                                             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194) 

如果您有任何想法，请分享，提前谢谢。

Answer 1

最终这篇帖子WRITE_EXTERNAL_STORAGE not working on lollipop even though it's set in the manifest 帮助了我。我所做的是更改AndroidManifest.xml 文件中的权限，如下所示：

 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="26" tools:replace="android:maxSdkVersion"/>

这样应用就不会崩溃！