> Cannot add task 'wrapper' as a task with that name already exists.

> Cannot add task 'wrapper' as a task with that name already exists. 说是在android/build.gradle 文件36行报错

最终发现原因是gradle版本问题

// 旧版本是:
task wrapper(type:Wrapper) {
    //configuration
}

// 新版本是：
wrapper {
    //configuration
}

改完之后，再次执行./gradlew assembleRelease

成功了。