【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 
众所周知，默认情况下，从水平变为垂直，Android的操作过程为关闭Activity，再在当前方向打开此Activity。此过程一般而言没有什么不妥，只是会带来一个问题：用户数据丢失，也就是说，Activity 重启，必然使得内容初始化。补救措施是在变换方向时保存当前内容，如webview的url等。
这种做法当然不够好玩。
正确的做法是，配置Activity的变化状态（这么说可能不大准确。），在AndroidManifest.xml中，对于每一个Activity的配置，有一个属性，android:configChanges=""。这个属性的官方解释是
通过设置这个属性可以使Activity捕捉设备状态变化，以下是可以被识别的内容：
CONFIG_FONT_SCALECONFIG_MCC
CONFIG_MNC
CONFIG_LOCALE
CONFIG_TOUCHSCREEN
CONFIG_KEYBOARD
CONFIG_NAVIGATION
那么，如下配置则可以完成我们想要的结果：
补充：
每一个config的具体说明：
| Value | Description |
| “mcc“ | The IMSI mobile country code (MCC) has changed — that is, a SIM hasbeen detected and updated the MCC.移动国家号码，由三位数字组成，每个国家都有自己独立的MCC，可以识别手机用户所属国家。 |
| “mnc“ | The IMSI mobile network code (MNC) has changed — that is, a SIM hasbeen detected and updated the MNC.移动网号，在一个国家或者地区中，用于区分手机用户的服务商。 |
| “locale“ | The locale has changed — for example, the user has selected a new language that text should be displayed in.用户所在地区发生变化。 |
| “touchscreen“ | The touchscreen has changed. (This should never normally happen.) |
| “keyboard“ | The keyboard type has changed — for example, the user has plugged in an external keyboard.键盘模式发生变化，例如：用户接入外部键盘输入。 |
| “keyboardHidden“ | The keyboard accessibility has changed — for example, the user has slid the keyboard out to expose it.用户打开手机硬件键盘 |
| “navigation“ | The navigation type has changed. (This should never normally happen.) |
| “orientation“ | The screen orientation has changed — that is, the user has rotated the device.设备旋转，横向显示和竖向显示模式切换。 |
| “fontScale“ | The font scaling factor has changed — that is, the user has selected a new global font size.全局字体大小缩放发生改变 |
来源：oschina
链接：https://my.oschina.net/u/107361/blog/23606