如何在分析中使用重复用户名检查注册

Question

我正在使用以下代码通过Swift在Parse帐户注册。

var user = PFUser()
user.username = self.userNameText.text
user.password = self.paswordText.text
user["mobileNumber"] = self.mobileNo as! String     //
user["authCode"] = self.authCode as! String
user["deviceId"] = deviceId
self.user.signUpInBackgroundWithBlock({
            (success:Bool, error:NSError?) -> Void in
            if (error == nil) {
                let installation:PFInstallation = PFInstallation.currentInstallation()
                installation["user"] = PFUser.currentUser()
                installation.saveInBackgroundWithBlock({
                    (success:Bool, error:NSError?) -> Void in
                    if (error == nil) {
                        println("Installion Success")
                    } else {
                        println("Installation Error")
                    }
                })
                println("Singup Success")
            } else { 
                println(" error = \(error)")
            }
})

在这种情况下，如果输入的用户名已经保存在Parse中，我想给出错误，但是现在它已经成功地用两个相同的用户名注册了。

我怎么才能避免呢？

Answer 1

如果要检查用户是否已通过Parse.com注册，则必须在用户表中进行查询，如果用户已经存在，则不允许他再次注册

PFQuery *query = [PFUser query];
[query whereKey:@"username" equalTo:textField.text];

[query getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
if (object != nil) {
    NSLog(@"User exist");
}
else
{
    NSLog(@"User don`t exist");
}
}]; 

希望这能帮到你

Answer 2

试试这个

var query = PFQuery(className:"User")
        query.whereKey(key: "username", equalTo:self.userNameText.text)

query.getFirstObjectInBackgroundWithBlock { (object: [AnyObject]?, error: NSError?) -> Void in
    if object != nil
    {
        //User exist
       //give appropriate message
    }
    else
    {
        //User don`t exist"
         //call signup method from here
        self.signUpNewUser()
    }
        }

新用户注册

func signUpNewUser()
{
var user = PFUser()
user.username = self.userNameText.text
user.password = self.paswordText.text
user["mobileNumber"] = self.mobileNo as! String     //
user["authCode"] = self.authCode as! String
user["deviceId"] = deviceId
self.user.signUpInBackgroundWithBlock({
            (success:Bool, error:NSError?) -> Void in
            if (error == nil) {
                let installation:PFInstallation = PFInstallation.currentInstallation()
                installation["user"] = PFUser.currentUser()
                installation.saveInBackgroundWithBlock({
                    (success:Bool, error:NSError?) -> Void in
                    if (error == nil) {
                        println("Installion Success")
                    } else {
                        println("Installation Error")
                    }
                })
                println("Singup Success")
            } else { 
                println(" error = \(error)")
            }
})
}