Android 6.0，代号棉花糖，自发布伊始，其主要的特征运行时权限就很受关注。因为这一特征不仅改善了用户对于应用的使用体验，还使得应用开发者在实践开发中需要做出改变。
没有深入了解运行时权限的开发者通常会有很多疑问，比如什么是运行时权限，哪些是运行时的权限，我的应用是不是会在6.0系统上各种崩溃呢，如何才能支持运行时权限机制呢。本文讲尝试回答这一些问题，希望读者阅读完成之后，都能找到较为完美的答案。
权限一刀切
在6.0以前的系统，都是权限一刀切的处理方式，只要用户安装，Manifest申请的权限都会被赋予，并且安装后权限也撤销不了。 这种情况下，当我们从Google Play安装一个应用，在安装之前会得到这样的权限提示信息。
当上述对话框弹出后，用户只有两种选择：
我信任你，即使有敏感权限 你一个**应用，要这个权限干嘛，我还是不安装了。
所以，这种一刀切的处理方式还是有弊端的，我们没有办法只允许某些权限或者拒绝某些权限。
棉花糖运行时权限
从棉花糖开始，Android系统引入了新的权限机制，即本文要讲的运行时权限。
何为运行时权限呢？举个栗子，以某个需要拍照的应用为例，当运行时权限生效时，其Camera权限不是在安装后赋予，而是在应用运行的时候进行请求权限（比如当用户按下”相机拍照“按钮后）看到的效果则是这样的
接下来，对于Camera权限的处理完全权交给用户。是不是有点像苹果系统的处理呢，不要说这是抄袭，暂且称为师夷长技以制夷。
权限的分组
Android中有很多权限，但并非所有的权限都是敏感权限，于是6.0系统就对权限进行了分类，一般为下述几类
正常(Normal Protection)权限 危险(Dangerous)权限 特殊(Particular)权限 其他权限（一般很少用到）
正常权限
正常权限具有如下的几个特点
对用户隐私没有较大影响或者不会打来安全问题。 安装后就赋予这些权限，
不需要显示提醒用户，用户也不能取消这些权限。
正常权限列表
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">6</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">7</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">8</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">9</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">10</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">11</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">12</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">13</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">14</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">15</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">16</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">17</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">18</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">19</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">20</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">21</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">22</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">23</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">24</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">25</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">26</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">27</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">28</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">29</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">30</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">31</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">32</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">33</span>
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
INTERNET
KILL_BACKGROUND_PROCESSES
MODIFY_AUDIO_SETTINGS
NFC
READ_SYNC_SETTINGS
READ_SYNC_STATS
RECEIVE_BOOT_COMPLETED
REORDER_TASKS
REQUEST_INSTALL_PACKAGES
SET_TIME_ZONE
SET_WALLPAPER
SET_WALLPAPER_HINTS
TRANSMIT_IR
USE_FINGERPRINT
VIBRATE
WAKE_LOCK
WRITE_SYNC_SETTINGS
SET_ALARM
INSTALL_SHORTCUT
UNINSTALL_SHORTCUT
上述的权限基本设计的是关于网络，蓝牙，时区，快捷方式等方面，只要在Manifest指定了这些权限，就会被授予，并且不能撤销。
特殊权限
这里讲特殊权限提前讲一下，因为这个相对来说简单一些。
特殊权限，顾名思义，就是一些特别敏感的权限，在Android系统中，主要由两个
SYSTEM_ALERT_WINDOW，设置悬浮窗，进行一些黑科技 WRITE_SETTINGS 修改系统设置
关于上面两个特殊权限的授权，做法是使用startActivityForResult启动授权界面来完成。
请求SYSTEM_ALERT_WINDOW
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">6</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">7</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">8</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">9</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">10</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">11</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">12</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">13</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">14</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">15</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">16</span>
private static final int REQUEST_CODE = 1;
private void requestAlertWindowPermission() {
Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
intent.setData(Uri.parse("package:" + getPackageName()));
startActivityForResult(intent, REQUEST_CODE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE) {
if (Settings.canDrawOverlays(this)) {
Log.i(LOGTAG, "onActivityResult granted");
}
}
}
上述代码需要注意的是
使用Action Settings.ACTION_MANAGE_OVERLAY_PERMISSION启动隐式Intent 使用"package:" + getPackageName()携带App的包名信息 使用Settings.canDrawOverlays方法判断授权结果
请求
WRITE_SETTINGS
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">6</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">7</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">8</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">9</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">10</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">11</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">12</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">13</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">14</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">15</span>
private static final int REQUEST_CODE_WRITE_SETTINGS = 2;
private void requestWriteSettings() {
Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS);
intent.setData(Uri.parse("package:" + getPackageName()));
startActivityForResult(intent, REQUEST_CODE_WRITE_SETTINGS );
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE_WRITE_SETTINGS) {
if (Settings.System.canWrite(this)) {
Log.i(LOGTAG, "onActivityResult write settings granted" );
}
}
}
上述代码需要注意的是
使用Action Settings.ACTION_MANAGE_WRITE_SETTINGS 启动隐式Intent 使用"package:" + getPackageName()携带App的包名信息 使用Settings.System.canWrite方法检测授权结果
注意：关于这两个特殊权限，一般不建议应用申请。
网上搜索得知当编译版本>=6.0 且运行在>=6.0的版本上 WRITE_SETTINGS权限无法获取即便运行上诉代码运行，除非将APP作为预装应用或者使用系统签名
危险权限
危险权限实际上才是运行时权限主要处理的对象，这些权限可能引起隐私问题或者影响其他程序运行。Android中的危险权限可以归为以下几个分组：
CALENDAR CAMERA CONTACTS LOCATION MICROPHONE PHONE SENSORS SMS STORAGE
各个权限分组与其具体的权限，可以参考下图：
必须要支持运行时权限么
目前应用实际上是可以不需要支持运行时权限的，但是最终肯定还是需要支持的，只是时间问题而已。
想要不支持运行时权限机制很简单，只需要将targetSdkVersion设置低于23就可以了，意思是告诉系统，我还没有完全在API 23（6.0）上完全搞定，不要给我启动新的特性。
不支持运行时权限会崩溃么
可能会，但不是那种一上来就噼里啪啦崩溃不断的那种。
如果你的应用将targetSdkVersion设置低于23，那么在6.0的系统上不会为这个应用开启运行时权限机制，即按照以前的一刀切方式处理。
然而有点糟糕的是
6.0系统提供了一个应用权限管理界面，界面长得是这样的
既然是可以管理，用户就能取消权限，当一个不支持运行时权限的应用某项权限被取消时
系统会弹出一个对话框提醒撤销的危害，如果用户执意撤销，会带来如下的反应
如果你的程序正在运行，则会被杀掉。 当你的应用再次运行时，可能出现崩溃
为什么会可能崩溃的，比如下面这段代码
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
String deviceId = telephonyManager.getDeviceId();
if (deviceId.equals(mLastDeviceId)) {//This may cause NPE
//do something
}
如果用户撤消了获取DeviceId的权限，那么再次运行时,deviceId就是null，如果程序后续处理不当，就会出现崩溃。
该来的还得来
6.0的运行时权限，我们最终都是要支持的，通常我们需要使用如下的API
int checkSelfPermission(String permission) 用来检测应用是否已经具有权限
void requestPermissions(String[] permissions, int requestCode) 进行请求单个或多个权限
void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) 用户对请求作出响应后的回调
以一个请求Camera权限为例
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">6</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">7</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">8</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">9</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">10</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">11</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">12</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">13</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">14</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">15</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">16</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">17</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">18</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">19</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">20</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">21</span>
@Override
public void onClick(View v) {
if (!(checkSelfPermission(Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED)) {
requestCameraPermission();
}
}
private static final int REQUEST_PERMISSION_CAMERA_CODE = 1;
private void requestCameraPermission() {
requestPermissions(new String[]{Manifest.permission.CAMERA}, REQUEST_PERMISSION_CAMERA_CODE);
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == REQUEST_PERMISSION_CAMERA_CODE) {
int grantResult = grantResults[0];
boolean granted = grantResult == PackageManager.PERMISSION_GRANTED;
Log.i(LOGTAG, "onRequestPermissionsResult granted=" + granted);
}
}
通常情况下，我们会得到这样的一个对话框
当用户选择允许，我们就可以在onRequestPermissionsResult方法中进行响应的处理，比如打开摄像头 当用户拒绝，你的应用可能就开始危险了
当我们再次尝试申请权限时，弹出的对话框和之前有点不一样了，主要表现为多了一个checkbox。如下图
当用户勾选了”不再询问“拒绝后，你的程序基本这个权限就Game Over了。
不过，你还有一丝希望，那就是再出现上述的对话框之前做一些说明信息，比如你使用这个权限的目的（一定要坦白）。
shouldShowRequestPermissionRationale这个API可以帮我们判断接下来的对话框是否包含”不再询问“选择框。
一个标准的流程
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">6</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">7</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">8</span>
if (!(checkSelfPermission(Manifest.permission.READ_CONTACTS) == PackageManager.PERMISSION_GRANTED)) {
if (shouldShowRequestPermissionRationale(Manifest.permission.READ_CONTACTS)) {
Toast.makeText(this, "Please grant the permission this time", Toast.LENGTH_LONG).show();
}
requestReadContactsPermission();
} else {
Log.i(LOGTAG, "onClick granted");
}
如何批量申请
批量申请权限很简单，只需要字符串数组放置多个权限即可。如请求代码
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
private static final int REQUEST_CODE = 1;
private void requestMultiplePermissions() {
String[] permissions = {Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_PHONE_STATE};
requestPermissions(permissions, REQUEST_CODE);
}
对应的界面效果是
注意：间隔较短的多个权限申请建议设置成单次多个权限申请形式，避免弹出多个对话框，造成不太好的视觉效果。
申请这么多权限岂不是很累
其实你不需要每个权限都去显式申请，举一个例子，如果你的应用授权了读取联系人的权限，那么你的应用也是被赋予了写入联系人的权限。因为读取联系人和写入联系人这两个权限都属于联系人权限分组，所以一旦组内某个权限被允许，该组的其他权限也是被允许的。
注意事项
API问题
由于checkSelfPermission和requestPermissions从API 23才加入，低于23版本，需要在运行时判断 或者使用Support Library v4中提供的方法
ContextCompat.checkSelfPermission ActivityCompat.requestPermissions ActivityCompat.shouldShowRequestPermissionRationale
多系统问题
当我们支持了6.0必须也要支持4.4，5.0这些系统，所以需要在很多情况下，需要有两套处理。比如Camera权限
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">1</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">2</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">3</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">4</span>
<span class="line-number" style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; line-height: inherit; font-family: inherit; vertical-align: baseline; color: rgb(147, 161, 161) !important;">5</span>
if (isMarshmallow()) {
requestPermission();//然后在回调中处理
} else {
useCamera();//低于6.0直接使用Camera
}
两个权限
运行时权限对于应用影响比较大的权限有两个，他们分别是
READ_PHONE_STATE WRITE_EXTERNAL_STORAGE/READ_EXTERNAL_STORAGE
其中READ_PHONE_STATE用来获取deviceID，即IMEI号码。这是很多统计依赖计算设备唯一ID的参考。如果新的权限导致读取不到，避免导致统计的异常。建议在完全支持运行时权限之前，将对应的值写入到App本地数据中，对于新安装的，可以采取其他策略减少对统计的影响。
WRITE_EXTERNAL_STORAGE/READ_EXTERNAL_STORAGE这两个权限和外置存储（即sdcard）有关，对于下载相关的应用这一点还是比较重要的，我们应该尽可能的说明和引导用户授予该权限。
些许建议
不要使用多余的权限，新增权限时要慎重 使用Intent来替代某些权限，如拨打电话（和你的产品经理PK去吧） 对于使用权限获取的某些值，比如deviceId，尽量本地存储，下次访问直接使用本地的数据值 注意，由于用户可以撤销某些权限，所以不要使用应用本地的标志位来记录是否获取到某权限。
注意
即使支持了运行时权限，也要在Manifest声明，因为市场应用会根据这个信息和硬件设备进行匹配，决定你的应用是否在该设备上显示。
是否支持运行时权限
个人觉得Marshmallow的运行时权限对于用户来说绝对是一个好东西，但是目前想要支持需要做的事情还是比较多的。
对于一个有很多依赖的宿主应用，想要做到支持还是有一些工作量的，因为你的权限申请受制于依赖。
建议在短期内暂时可以不考虑支持该运行时权限机制,等时机成熟或者简单易用的第三方库完善之后再支持也未尝不可。
