Question

我在textFieldShouldReturn上有这个代码（与调用的方法不在同一个类中）：

  - (BOOL)textFieldShouldReturn:(UITextField *)textField {
     LoginViewController *loginViewController = [[LoginViewController alloc]init];

     if (textField.returnKeyType == UIReturnKeyJoin) [loginViewController logIn];
     return (textField.returnKeyType == UIReturnKeyDone);
}

到目前为止，一切都很完美，这是＆＃34; 登录＆＃34;的代码。方法：

  - (IBAction)logIn{

      NSString *username = [[self.usernameLoginField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] lowercaseString];
      NSString *password = [[self.passwordLoginField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] lowercaseString];

      NSLog(@"Username: %@ - Password: %@ ",username,password);
      //Whatever
}

在我的view上，我有一个调用该方法的按钮，当我使用该按钮时NSLog显示UITextField在那一刻包含的内容，否则，如果方法是来自＆＃34; 加入＆＃34;从键盘输入（返回键），NSLog在变量上显示空内容我错过了什么？。

Answer 1

在我看来，你有3个可能的解决方案：

选项1：最佳选择恕我直言。

您可以将UIAlertView与UIAlertViewStyle = UIAlertViewStyleLoginAndPasswordInput

一起使用

self.alertView = [[UIAlertView alloc] initWithTitle:nil
                                            message:@"LogIn"
                                           delegate:self
                                  cancelButtonTitle:nil
                                  otherButtonTitles:@"Cancel", @"Join", nil];

self.alertView.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput;

[self.alertView show];

然后与代表：

- (void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if (alertView == self.alertView)
    {
        if (buttonIndex == 1)
        {
            [self logIn:[[alertView textFieldAtIndex:0] text] andPassword:[[alertView textFieldAtIndex:1] text]];
        }
        else if (buttonIndex == 0)
        {
            [self.navigationController popViewControllerAnimated:YES];

        }
    }
}

请务必添加：UIAlertViewDelegate

选项2：

使用[self performSegueWithIdentifier:@"identifier" sender:self]和 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

#pragma mark - UITextFieldDelegate

- (BOOL) textFieldShouldReturn:(UITextField *)textField
{
    if (textField == self.usernameLoginField)
    {
        [self.usernameLoginField resignFirstResponder];
        [self.passwordLoginField becomeFirstResponder];
    }
    else if (textField == self.passwordLoginField)
    {
        [self.passwordLoginField resignFirstResponder];

        //This Identifier is in the Storyboard
        [self performSegueWithIdentifier:@"option2Segue" sender:self];

    }

    return true;
}


 #pragma mark - Navigation

 // In a storyboard-based application, you will often want to do a little preparation before navigation
 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
 {
      [(YourViewController *)segue.destinationViewController setUsername:self.usernameLoginField.text];
      [(YourViewController *)segue.destinationViewController setPassword:self.passwordLoginField.text];
      }

在YourViewController.h中，您需要：

@property (nonatomic, strong) NSString* username;
@property (nonatomic, strong) NSString* password;

请务必添加：UITextFieldDelegate

选项3

要发回信息，您应该使用委托：

在firstViewController.h：

中

#import "DelegateViewController.h"

@interface FirstViewController：UIViewController

（void）logIn：（NSString *）用户名密码：（NSString *）密码;

在firstViewController.m：

中

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"option3Delegate"])
    {
        ((DelegateViewController *) segue.destinationViewController).delegate = self;
    }
}

在delegateViewController.h：

中

@protocol Option3Delegate <NSObject>

- (void) logIn: (NSString *) username password: (NSString *) password;

@end

@interface DelegateViewController : UIViewController
{
    id myDelegate;
}

@property (nonatomic, assign) id<Option3Delegate> delegate;

@end

在delegateViewController.m：

中

#pragma mark - UITextFieldDelegate

- (BOOL) textFieldShouldReturn:(UITextField *)textField
{
    if (textField == self.usernameLoginField)
    {
        [self.usernameLoginField resignFirstResponder];
        [self.passwordLoginField becomeFirstResponder];
    }
    else if (textField == self.passwordLoginField)
    {
        [self.passwordLoginField resignFirstResponder];

        //This Identifier is in the Storyboard

        if ([_delegate respondsToSelector:@selector(logIn:password:)])
        {
            [_delegate logIn:self.usernameLoginField.text password:self.passwordLoginField.text];
        }

        [self.navigationController popViewControllerAnimated:YES];
    }

    return true;
}

请务必添加：UITextFieldDelegate

选项4：使用KeyboardController

KeyboardController是一个小型解决方案，用于处理UITextFields内的键盘交互。但是只能处理Next和Done Return键。要处理Join键，您可以在ViewController中执行此操作。在您分配KeyboardController的视图控制器中：

@property (strong, nonatomic) IBOutlet UITextField *usernameLoginField;
@property (strong, nonatomic) IBOutlet UITextField *passwordLoginField;
@property (strong, nonatomic) KeyboardController *keyboardController;


- (void)viewDidLoad
{
    [super viewDidLoad];

    id fields = @[self.usernameLoginField, self.passwordLoginField];
    self.keyboardController = [KeyboardController controllerWithFields:fields];

    //Important
    self.passwordLoginField.delegate = self;
}

#pragma mark - UITextFieldDelegate

- (BOOL) textFieldShouldReturn:(UITextField *)textField
{
    if (textField == self.passwordLoginField)
    {
        [self.passwordLoginField resignFirstResponder];
        [self logIn];
    }

    return true;
}

- (IBAction)logIn
{
    NSLog(@"Username: %@ - Password: %@", self.usernameLoginField.text, self.passwordLoginField.text);
    //Whatever
}

你可以download an example with the 4 options here：

textFieldShouldReturn忽略变量

1 个答案: