如何在运行时在Android Marshmallow中获得CLEAR_APP_CACHE权限?

问题描述：

代码:

void clearCache() {

    if (mClearCacheObserver == null) {
        mClearCacheObserver = new CachePackageDataObserver();
    }

    PackageManager mPM = getPackageManager();

    @SuppressWarnings("rawtypes")
    final Class[] classes = {Long.TYPE, IPackageDataObserver.class};

    Long localLong = Long.valueOf(CACHE_APP);


    try {
        Method localMethod =
                mPM.getClass().getMethod("freeStorageAndNotify", classes);

        localMethod.setAccessible(true);
        // Start of inner try-catch block

        try {
            localMethod.invoke(mPM, localLong, mClearCacheObserver);

        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            // TODO Auto-generated catch block
            e.getCause().printStackTrace();
        }

        // End of inner try-catch block

    } catch (NoSuchMethodException e1) {

        e1.printStackTrace();
    }

}

Logcat :

java.lang.SecurityException: Neither user 10206 nor current process has android.permission.CLEAR_APP_CACHE.
     at android.os.Parcel.readException(Parcel.java:1620)
     at android.os.Parcel.readException(Parcel.java:1573)
     at android.content.pm.IPackageManager$Stub$Proxy.freeStorageAndNotify(IPackageManager.java:5081)
     at android.app.ApplicationPackageManager.freeStorageAndNotify(ApplicationPackageManager.java:2500)
     at android.content.pm.PackageManager.freeStorageAndNotify(PackageManager.java:4710)
     at java.lang.reflect.Method.invoke(Native Method)
     at com.onexsoftech.clearcacheapp.MainActivity.clearCache(MainActivity.java:278)
     at com.onexsoftech.clearcacheapp.MainActivity.insertDummyContactWrapper1(MainActivity.java:495)
     at com.onexsoftech.clearcacheapp.MainActivity.insertDummyContact(MainActivity.java:472)

答

在Android 6.0之前，

Prior to Android 6.0, CLEAR_APP_CACHE had a protectionLevel of dangerous, so ordinary SDK apps could request it in the manifest.

从Android 6.0开始， CLEAR_APP_CACHE的protectionLevel为signature|privileged .普通的Android应用无法持有此权限.仅当您的应用程序使用固件的签名密钥签名或您安装在特权系统分区上时，您才能持有此权限.

As of Android 6.0, CLEAR_APP_CACHE has a protectionLevel of signature|privileged. Ordinary Android apps cannot hold this permission. You can only hold this permission if your app is signed with the firmware's signing key or you are installed on the privileged system partition.

如何在运行时在Android Marshmallow中获得CLEAR_APP_CACHE权限?

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