实体类别

@Entity(tableName = "user_table")
data class User(
    @PrimaryKey(autoGenerate = true)
    //....
) {

    constructor(
        userID: Int
    ) : this(
        userID,
        //...
    )
}

刀类

@Dao
interface UserDao {
    @Insert(onConflict = IGNORE)
    fun addUser(user: User): Long
    
    //.......
}

资料档案库类

class RoomUserRepository(context: Context) {
    //...
    suspend fun addUser(user: User): Long = userDao.addUser(user)
    //...
}

视图模式类

class UserViewModel(val context: Application) : AndroidViewModel(context) {
    //...

    var userID: Long = 0

    fun addUser(user: User) {
        viewModelScope.launch(Dispatchers.IO) {
            userID = roomUserRepository.addUser(user)
        }
    }

    //...
}

注册按钮onclick{}

clicked = !clicked
if (confirmpassword != password) {
    message = "Incorrect password! please try again"
} else if (inputChack(fullname, email, password)) {
    message = "Information is incomplete"
} else {
    // Create User
    user.email = email
    user.fullName = fullname
    user.password = password
    userVM.addUser(user)
    // Create Cart
    cart.userID = userVM.userID.toInt()
    cartVM.addCart(cart)
    Log.d("user & cart", "adding users & cart")
}

正如您所看到的，当用户单击SIGN UP时，我将在我的数据库中创建User & Cart，用户创建工作正常，但当我创建购物车时，我必须传递用户ID，我从userID变量中获取它，您可以在ViewMode Class中找到它，问题是值正在获取cart.userID = userVM.userID.toInt()，然后更新了它
我只想
调用userVM.addUser(user)后，我必须等到userID变量得到更新（查看ViewMode类），然后我得到更新后的值cart.userID = userVM.userID.toInt()