Android手动检查并申请权限

Android权限一般是在AndroidManifest.xml中声明,在安装或首次使用的时候系统会自动提示用户是否提供权限

Android官方文档:

Then, when the application is installed on the device, the installer determines whether or not to grant the requested permission by checking the authorities that signed the application’s certificates and, in some cases, asking the user. If the permission is granted, the application is able to use the protected features. If not, its attempts to access those features will simply fail without any notification to the user.

但有时候因为手机设备等原因,并没有在一开始就弹出提示框让用户确认是否提供权限,对于有些权限,不确认的话就不提供权限,因此,有些功能就无法实现。
这时候需要我们手动检查是否已经拥有权限,没有的话就调用代码提示用户提供权限。

如何手动检查并申请权限
如:在写入之前检查是否有WRITE_EXTERNAL_STORAGE权限,没有则申请权限
代码:

if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED) {
    //申请WRITE_EXTERNAL_STORAGE权限
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
            WRITE_EXTERNAL_STORAGE_REQUEST_CODE);
}

请求权限后,系统会弹出请求权限的Dialog,允许即可

用户选择允许或拒绝后,会回调onRequestPermissionsResult方法, 该方法类似于onActivityResult

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    doNext(requestCode,grantResults);
}



PS:
在Android6.0,有些权限只需要在AndroidManifest.xml文件中声明即可,但有些除了声明以外,还需要在运行时判断,即用户确认,需要确认的权限如下:

身体传感器
日历
摄像头
通讯录
地理位置
麦克风
电话
短信
存储空间

Android6.0系统默认为targetSdkVersion小于23的应用默认授予了所申请的所有权限,
所以如果你以前的APP设置的targetSdkVersion低于23,在运行时也不会崩溃,
但这也只是一个临时的救急策略,用户还是可以在设置中取消授予的权限。

以下权限只需要在AndroidManifest.xml中声明即可使用:

android.permission.ACCESS_LOCATION_EXTRA_COMMANDS
android.permission.ACCESS_NETWORK_STATE
android.permission.ACCESS_NOTIFICATION_POLICY
android.permission.ACCESS_WIFI_STATE
android.permission.ACCESS_WIMAX_STATE
android.permission.BLUETOOTH
android.permission.BLUETOOTH_ADMIN
android.permission.BROADCAST_STICKY
android.permission.CHANGE_NETWORK_STATE
android.permission.CHANGE_WIFI_MULTICAST_STATE
android.permission.CHANGE_WIFI_STATE
android.permission.CHANGE_WIMAX_STATE
android.permission.DISABLE_KEYGUARD
android.permission.EXPAND_STATUS_BAR
android.permission.FLASHLIGHT
android.permission.GET_ACCOUNTS
android.permission.GET_PACKAGE_SIZE
android.permission.INTERNET
android.permission.KILL_BACKGROUND_PROCESSES
android.permission.MODIFY_AUDIO_SETTINGS
android.permission.NFC
android.permission.READ_SYNC_SETTINGS
android.permission.READ_SYNC_STATS
android.permission.RECEIVE_BOOT_COMPLETED
android.permission.REORDER_TASKS
android.permission.REQUEST_INSTALL_PACKAGES
android.permission.SET_TIME_ZONE
android.permission.SET_WALLPAPER
android.permission.SET_WALLPAPER_HINTS
android.permission.SUBSCRIBED_FEEDS_READ
android.permission.TRANSMIT_IR
android.permission.USE_FINGERPRINT
android.permission.VIBRATE
android.permission.WAKE_LOCK
android.permission.WRITE_SYNC_SETTINGS
com.android.alarm.permission.SET_ALARM
com.android.launcher.permission.INSTALL_SHORTCUT
com.android.launcher.permission.UNINSTALL_SHORTCUT

参考文档:

博客
http://www.aswifter.com/2015/11/04/android-6-permission/
Android官方文档
http://androiddoc.qiniudn.com/guide/topics/manifest/manifest-intro.html#perms

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