在文件[flutter项目]\android\build.gradle中，注释掉一行代码就行。
rootProject.buildDir = '../build'
subprojects {
// project.buildDir = "${rootProject.buildDir}/${project.name}" // 把这行注释掉，在flutter运行的时候，记得取消这行的注释
}
subprojects {
project.evaluationDependsOn(':app')
}
tasks.register("clean", Delete) {
delete rootProject.buildDir
}
