android source code 备忘

１　android 5.0, encrypt phone，必须电量达到８０％以上．

packages/apps/Settings
./src/com/android/settings/CryptKeeperSettings.java
   

 // Minimum battery charge level (in percent) to launch encryption.  If the battery charge is
    // lower than this, encryption should not be activated.
    private static final int MIN_BATTERY_LEVEL = 1;

 2  setMobileDataEnabled() 4.4和之前版本是可用的，android 5.0之后， 所以不能通过代码反射，只能手动去关闭mobile data（uiautormator也可以呀） 4.4 code:

  5.1 code:

 

http://stackoverflow.com/questions/26539445/the-setmobiledataenabled-method-is-no-longer-callable-as-of-android-l-and-later

 

 3 Anroid 升级到M之后，很多代码发生变化。有些代码只能在M上使用，会提示 Call requires API level 23 (current min is 。。) 。这时候需要区分注明这个只能在M上用，可以加：

@TargetApi(Build.VERSION_CODE.M)

 4