导航栏NavigationBar
源码部分：
frameworks/base/services/core/java/com/android/server/policy/PhoneWindowManager.java
mHasNavigationBar = res.getBoolean(com.android.internal.R.bool.config_showNavigationBar);// Allow a system property to override this. Used by the emulator.// See also hasNavigationBar().String navBarOverride = SystemProperties.get("qemu.hw.mainkeys");if ("1".equals(navBarOverride)) {mHasNavigationBar = false;} else if ("0".equals(navBarOverride)) {mHasNavigationBar = true;}
显示方案：
[1]使用adb命令开启Android手机虚拟按键（导航栏）adb rootadb remountadb shell$ getprop qemu.hw.mainkeys #查看值$ setprop qemu.hw.mainkeys 0 #设置值为0，属性值为1 表示未打开虚拟按键，属性值为0表示一直打开虚拟按键$ stop$ start
[2]修改config.xml文件
设置config_showNavigationBar为true就可以打开系统的虚拟键
framework/base/core/res/res/values/config.xml<!-- Whether a software navigation bar should be shown. NOTE: in the future this may beautodetected from the Configuration. --><bool name="config_showNavigationBar">true</bool><!--<bool name="config_supportSystemNavigationKeys">false</bool>-->
一般这种config 文件都会有overlay文件，所以也需要修改对应的device下的overlay文件
device\qcom\msm8953_64\overlay\frameworks\base\core\res\res\values\config.xml<!-- Whether a software navigation bar should be shown. NOTE: in the future this may beautodetected from the Configuration. --><bool name="config_showNavigationBar">true</bool><!--<bool name="config_supportSystemNavigationKeys">false</bool>-->
[3]添加配置文件
添加qemu.hw.mainkeys=0，也就是修改 androdi系统的system/build.prop
device\qcom\msm8953_64\system.propqemu.hw.mainkeys=0
