Android Studio 真机调试 Changes were not applied. No running app....

Question

Changes were not applied. No running app process found.
Android Studio 真机调试，遇到这个问题，每次更改代码都会遇到这个问题，哪怕是你修改了一行代码，遇到这个问题就要在手机上重装一次APP，这小一分钟就过去了

// 声明个变量都要重装
String a = "1";

我每天修改代码起码几十次吧，每次应用更改我都得等小一分钟，这怎么解决啊？