Android程序运行时权限与文件系统权限,与普通权限及危险权限的区别

面试时遇到这样的题目

 简述下Android程序运行时权限与文件系统权限的区别?

 

问题来的太突然，完全没有准备，结果我想到了android 6.0之后推出的 normal permissions 和 dangerous permissions

并且把这两者之间的关系答了一下，而且还举了个例子，现在想想，真是丢人

关于普通权限和危险权限，我把android 官网这个粘过来，给大家看看

If your app lists normal permissions in its manifest (that is, permissions that don't pose much risk to the user's privacy or the device's operation), the system automatically grants those permissions. If your app lists dangerous permissions in its manifest (that is, permissions that could potentially affect the user's privacy or the device's normal operation), the system asks the user to explicitly grant those permissions. The way Android makes the requests depends on the system version, and the system version targeted by your app:

• If the device is running Android 6.0 (API level 23) or higher, and the app's targetSdkVersion is 23 or higher, the app requests permissions from the user at run-time. The user can revoke the permissions at any time, so the app needs to check whether it has the permissions every time it runs. For more information about requesting permissions in your app, see the Working with System Permissions training guide.
• If the device is running Android 5.1 (API level 22) or lower, or the app's targetSdkVersion is 22 or lower, the system asks the user to grant the permissions when the user installs the app. If you add a new permission to an updated version of the app, the system asks the user to grant that permission when the user updates the app. Once the user installs the app, the only way they can revoke the permission is by uninstalling the app.

Normal and Dangerous Permissions

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System permissions are divided into several protection levels. The two most important protection levels to know about are normal and dangerouspermissions:

• Normal permissions cover areas where your app needs to access data or resources outside the app's sandbox, but where there's very little risk to the user's privacy or the operation of other apps. For example, permission to set the time zone is a normal permission. If an app declares that it needs a normal permission, the system automatically grants the permission to the app. For a full listing of the current normal permissions, see Normal permissions.
• Dangerous permissions cover areas where the app wants data or resources that involve the user's private information, or could potentially affect the user's stored data or the operation of other apps. For example, the ability to read the user's contacts is a dangerous permission. If an app declares that it needs a dangerous permission, the user has to explicitly grant the permission to the app.

那么哪些是安全权限呢？

下面这些都是安全权限：

As of API level 23, the following permissions are classified as PROTECTION_NORMAL:

• ACCESS_LOCATION_EXTRA_COMMANDS
• ACCESS_NETWORK_STATE
• ACCESS_NOTIFICATION_POLICY
• ACCESS_WIFI_STATE
• BLUETOOTH
• BLUETOOTH_ADMIN
• BROADCAST_STICKY
• CHANGE_NETWORK_STATE
• CHANGE_WIFI_MULTICAST_STATE
• CHANGE_WIFI_STATE
• DISABLE_KEYGUARD
• EXPAND_STATUS_BAR
• GET_PACKAGE_SIZE
• INSTALL_SHORTCUT
• INTERNET
• KILL_BACKGROUND_PROCESSES
• MODIFY_AUDIO_SETTINGS
• NFC
• READ_SYNC_SETTINGS
• READ_SYNC_STATS
• RECEIVE_BOOT_COMPLETED
• REORDER_TASKS
• REQUEST_IGNORE_BATTERY_OPTIMIZATIONS
• REQUEST_INSTALL_PACKAGES
• SET_ALARM
• SET_TIME_ZONE
• SET_WALLPAPER
• SET_WALLPAPER_HINTS
• TRANSMIT_IR
• UNINSTALL_SHORTCUT
• USE_FINGERPRINT
• VIBRATE
• WAKE_LOCK
• WRITE_SYNC_SETTINGS

那么你会问我那么这些东西到底有什么用呢？其实没啥用，只是android 6.0对权限进行了分类了，而且android 6.0还规定，如果你的项目的目标版本是6.0以上的，那么你的代码需要在用户需要获得权限的时候进行动态的提醒用户，或者让用户手动打开权限。不过，只要你把目标版本改为6.0以下，那么就只需要在清单文件声明一下就可以啦。

------未完 待续