1、如果在签名时android studio报"Master password is required to unlock the password database.The password database will be unlocked during this session for all subsystems."
那么直接点击弹窗右下角的“Reset”按钮，再输入密码和确认密码就好了。
2、选择版本类型时signtrue versions无法勾选，一般不会出现这种情况，我是在二次打包的时候不知道怎么搞的，反正就是不能选中，但是这时候是可以实际“Finish”的，所以不用管它，直接点击Finish就行了。
3、Error:Execution failed for task ':app:lintVitalRelease'.
> Lint found fatal errors while assembling a release target.
To proceed, either fix the issues identified by lint, or modify your build script as follows:
...
这个studio有直接给出解决办法：
android {
lintOptions {
checkReleaseBuilds false
// Or, if you prefer, you can continue to check for errors in release builds,
// but continue the build even when errors are found:
abortOnError false
}
}