Question

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的：

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)

Answer 1

在Android 6.0 CLEAR_APP_CACHE had a protectionLevel of dangerous之前，普通的SDK应用可以在清单中请求它。

自Android 6.0起，CLEAR_APP_CACHE has a protectionLevel of signature|privileged。普通的Android应用无法拥有此权限。如果您的应用程序使用固件的签名密钥签名，或者您已安装在特权系统分区上，则只能保留此权限。

Answer 2

来自Android M - ＆gt; CLEAR_APP_CACHE，保护级别：系统|签名

Android 6.0不会改变正常权限的行为（全部非危险权限，包括普通，系统和签名权限）。

因此无法在运行时请求该权限。更准确地说

签名系统权限，意味着它只能被保留使用固件的签名密钥签名或已安装的应用程序在系统分区上（例如，由有根设备的用户）。来自this stackoverflow Q / A.

文档： https://source.android.com/devices/tech/config/runtime_perms.html#affected-permissions

Answer 3

在AndroidManifest.xml中添加权限

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

为请求代码创建一个常量。

<强> Constants.java

public static final int REQUEST_CODE_FOR_PERMISSION = 501;

申请许可： -

public static void requestPermissionForClearCache(Activity activity) {
    if (ActivityCompat.checkSelfPermission(activity, Manifest.permission.CLEAR_APP_CACHE) != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.CLEAR_APP_CACHE)) {
            ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.CLEAR_APP_CACHE}, Constatnts.REQUEST_CODE_FOR_PERMISSION);
        } else {
            ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.CLEAR_APP_CACHE}, Constatnts.REQUEST_CODE_FOR_PERMISSION);
        }
    }
}

在片段中覆盖下面的方法。

@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    if (requestCode == Constatnts.REQUEST_CODE_FOR_PERMISSION && grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        // permission was granted successfully
    } else {
        // permission was NOT granted successfully
    }
}

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

3 个答案: