使用 Lambda 的 ViewModel

ViewModel.kt

fun getTokenAsync(action: (Token) -> Unit) {
    ......
}

fun verifyAsync(
    token: Token,
    userName: String,
    action: (Boolean) -> Unit
) {
    ......
}

fun requestAndSaveUserDataAsync(
    userName: String, 
    result: (Result) -> Unit
) {
    ......
}

......

fun login(userName: String) {
    getTokenAsync { token ->
        verifyAsync(token, userName) { verifyResult ->
            requestAndSaveUserDataAsync(userName) { result ->
                showLoginSuccess("Success")
            }
        }
    }
}