Question

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
if([newString length]>=1)
{
    NSString *sepStr=[newString substringToIndex:1];
    return !([sepStr length]>1);
}

if ([string length] == 0 && range.length > 0){
    textField.text = [textField.text stringByReplacingCharactersInRange:range withString:string];
    return NO;
}
NSCharacterSet *nonNumberSet = [[NSCharacterSet characterSetWithCharactersInString:@"0123456789"] invertedSet];
if ([string stringByTrimmingCharactersInSet:nonNumberSet].length > 0)return YES;}

- (IBAction)btnc:(id)sender {

    if([_textfield.text length]>2)
    {
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"WARNING" message:@"Please Fill The Mendatory Fields." preferredStyle:UIAlertControllerStyleAlert];
        [self presentViewController:alert animated:YES completion:nil];
        UIAlertAction* OK = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
                             {
                             }];
        [alert addAction:OK];

    }
    else{
        desViewController *face=[self.storyboard instantiateViewControllerWithIdentifier:@"REar"];
        [self.navigationController pushViewController:face animated:YES];
    }

我有一个应用，我想在UITextField中输入一个数值。但是我想只允许输入2位数字，而只允许输入1到31位数字。知道我怎么能修改它只接受限制在2位数和1到31位的数值？

Answer 1

你走了创建仅支持2个数字值的文本字段：

  - (BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString*)string
    {
      if (textField== _textfield) {
            int MAXLENGTH=2;
            NSString *newText = [_textfield.text stringByReplacingCharactersInRange:range withString:string];
            if(newText.length>MAXLENGTH) {
                return NO;
            }
            return YES;
        }
        return YES;
    }

仅限1到31（在目标C中），您可以检查如下验证：=

if([_textfield.text intValue]<=31 && [_textfield.text intValue]>0)
    {
        [_textfield resignFirstResponder];
   //Your Code
    }

Answer 2

试试这个：

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

    if(textField.text.length == 0 && [string  isEqual: @" "] )
    {
        return NO;
    }
    else
    {
        NSString* str = [NSString stringWithFormat:@"%@%@",textField.text,string];
        NSNumber* value = nil;
        NSNumberFormatter* format = [[NSNumberFormatter alloc] init];
        value  = [format numberFromString:str];//returns and
        if (value == nil){
            //do something useful i.e. show alert
            return NO;
        }
        else if (value.intValue > 31)
        {
            return NO;
        }
        else
        {
            return YES;
        }
    }

    return YES;
}

Answer 3

首先将keybordType设置为NumberPad，以便您的UITextField不支持除数字之外的任何内容。然后让你的UITextField听取其中的编辑事件。

[mTextField setKeyboardType:UIKeyboardTypeNumberPad];
[mTextField addTarget:self action:@selector(textFieldDidChange:) forControlEvents: UIControlEventEditingChanged];

现在＆＃39; textFieldDidChange＆＃39;方法应该是这样的。除了1到31之间的数字之外，它不会接受任何输入。

- (void) textFieldDidChange : (id) sender {
    NSString *text = [mTextField text];
    if (text == nil) {
        return;
    }

    int value = text.intValue ;
    if (value < 1) {
        [mTextField setText:@""];
        return;
    }

    if (value > 31) {
        NSString * val = [NSString stringWithFormat:@"%d", value];
        val = [val substringToIndex: (val.length - 1)];
        [mTextField setText:val];
    }
}

我希望这肯定会有所帮助。

Answer 4

让你的逻辑简单明了。

让textField仅允许Number Type输入：

self.yourTextField.keyboardType = UIKeyboardTypeNumberPad;

然后在-textField:shouldChangeCharactersInRange:replacementString:

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSString *str = [NSString stringWithFormat:@"%@%@", textField.text, string];
    long intValue = str.integerValue;
    if (intValue < 1 || intValue > 31) {
        self.yourTextField.text = textField.text;
        return NO;
    }
    return YES;
}

如何使文本字段只允许1到31的数字[目标C]

4 个答案: