调用反射方法时Android中的SecurityException

Question

我正在开发一个Cache-Cleaner应用程序,当我在PackageManager中调用一个隐藏方法时,我得到一个SecurityException,虽然我给了我的应用程序使用权限"DELETE_CACHE_FILES"

用途 - 权限:

uses-permission android:name="android.permission.DELETE_CACHE_FILES"
uses-permission android:name="android.permission.CLEAR_APP_CACHE"
uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
uses-permission android:name="android.permission.CLEAR_APP_USER_DATA"
uses-permission android:name="android.permission.GET_PACKAGE_SIZE"

反映方法:

Method method = getPackageManager().getClass().getMethod("deleteApplicationCacheFiles", String.class, IPackageDataObserver.class);

错误:

java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at <MY_PACKAGE_NAME>.MainActivity$1.onClick(MainActivity.java:70)
at android.view.View.performClick(View.java:2485)
at android.view.View$PerformClick.run(View.java:9080)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3683)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.SecurityException: Neither user 10037 nor current process has   android.permission.DELETE_CACHE_FILES.
at android.os.Parcel.readException(Parcel.java:1322)
at android.os.Parcel.readException(Parcel.java:1276)
at android.content.pm.IPackageManager$Stub$Proxy.deleteApplicationCacheFiles(IPackageManager.java:2346)
at android.app.ContextImpl$ApplicationPackageManager.deleteApplicationCacheFiles(ContextImpl.java:2562)
... 14 more

第70行:

 method.invoke(getPackageManager(), app.packageName, dataObserver);

它说我没有得到许可,但我已经在我的清单中删除了它...

编辑:我发现了这个;

W/PackageManager(62): Not granting permission android.permission.DELETE_CACHE_FILES to package <MY_PACKAGE_NAME>.cachecleaner (protectionLevel=3 flags=0x8be46)

EDIT2:deleteApplicationCacheFiles的声明(通过method.toGenericString()获取):

public void android.app.ContextImpl$ApplicationPackageManager.deleteApplicationCacheFiles(java.lang.String, android.content.pm.IPackageDataObserver)

Answer 1

DELETE_CACHE_FILES是一种signature|system权限,这意味着它只能由使用固件的签名密钥签名或安装在系统分区上的应用程序(例如,由root用户设备用户)保存.普通的SDK应用程序无法保留此权限.