一台华为的定制机在开发时，发现在logcat中无法查看到log信息，猜测是手机的出厂设置时把log输也给关闭了，网上查了一下解决方案如下：
Dial this: *#*#2846579#*#*
Service menu will appear.
Go to “ProjectMenu” -> “Background Setting” -> “Log Setting”
Open “Log switch” and set it to ON.
Open “Log level setting” and set the log level you wish.
Reboot the phone.