如何将焦点设置到iPhone中的下一个uitextfield？

Question

我有8个用于密码的uitextfields。每个文本字段包含一个来自密码的字母。当我键入一个字母，然后当我按下第二个键时，焦点移动到下一个文本框。但我想要的是，只要我完成了第一个字符的输入，焦点应该移动到下一个文本字段，而不用按其他键或按Tab键。我怎样才能做到这一点？任何示例代码教程？我使用的代码如下。

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 
{ 
    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(keyPressed:) name: UITextFieldTextDidChangeNotification object: nil]; 
    // Try to find next responder 

    UIResponder* nextResponder = [textField.superview viewWithTag:nextTag]; 
    if (nextResponder) { 
     // Found next responder, so set it. 
     //nextTag += 1; 
     [nextResponder becomeFirstResponder]; 
     if ([nextResponder tag] == 308) { 
      //[self performSelector:@selector(checkPassCode) withObject:nil afterDelay:0.0]; 
      [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(checkPassCode) userInfo:nil repeats:NO]; 
      lastResponder = nextResponder; 
     } 
     return YES; 
    } else { 
     [textField resignFirstResponder]; 
     return NO; 
    } 
} 


-(void) keyPressed: (NSNotification*) notification 
{ 
    nextTag += 1; 
    [[NSNotificationCenter defaultCenter] removeObserver: self name:UITextFieldTextDidChangeNotification object: nil]; 
} 

Answer 1

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { 

    NSString *finalString = [textField.text stringByReplacingCharactersInRange:range withString:string]; 

    if ([finalString length] > 0) { 
     textField.text = string; 

     UIResponder* nextResponder = [textField.superview viewWithTag:(textField.tag + 1)]; 
     if (nextResponder) { 
      [nextResponder becomeFirstResponder]; 

      // Your code for checking it. 
     } 

     return NO; 
    } 

    return YES; 
} 

希望这有助于。

雨燕3.2

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { 
    let finalString: String? = (textField.text? as NSString).replacingCharacters(in: range, with: string) 
    if (finalString?.characters.count ?? 0) > 0 { 
     textField.text = string 
     let nextResponder: UIResponder? = textField.superview?.viewWithTag((textField.tag + 1)) 
     if nextResponder != nil { 
      nextResponder?.becomeFirstResponder() 
      // Your code for checking it. 
     } 
     return false 
    } 
    return true 
} 

雨燕4.1

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { 
    let finalString: String? = (textField.text as NSString?)?.replacingCharacters(in: range, with: string) 
    if finalString?.count > 0 { 
     textField.text = string 
     let nextResponder: UIResponder? = textField.superview?.viewWithTag(textField.tag + 1) 
     if nextResponder != nil { 
      nextResponder?.becomeFirstResponder() 
      // Your code for checking it. 
     } 
     return false 
    } 
    return true 
} 

Answer 2

试试这个新增通知在viewDidLoad中，

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(limitTextField:) name:@"UITextFieldTextDidChangeNotification" object:txtField1]; 

- (void)limitTextField:(NSNotification *)note { 
    if(txtField1.tag==1) 
    { 
     if ([[txtField1 text] length] > 1) 
     { 
      [txtField1 resignFirstResponder]; 
      [txtField2 becomeFirstResponder]; 
     } 
    } 
} 

Answer 3

-(BOOL)textFieldShouldReturn:(UITextField *)textField { 

    if (textField ==firstTextField) { 
     [secondTextField becomeFirstResponder]; 
    }else if (textField == secondTextField){ 
     [thirdTextField becomeFirstResponder]; 
    }else if (textField == thirdTextField){ 
     [fourthTextField becomeFirstResponder]; 
    }else{ 
     [textField resignFirstResponder]; 
    } 
     return YES; 
}