How to gain permission and delay for user clicking in Kotlin

1. 绑定一个按钮事件：
`button.setOnClickListener({ view -> doSomething() })`

2. 申请一个权限并 delay waiting for user
```
// get permission
// import android.Manifest
if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED) {

    ActivityCompat.requestPermissions(this,
            arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE), 999)

    Thread.sleep(7 * 1000)
}
```