UITextField数字输入限制

落日映苍穹つ 2022-03-21 03:51 361阅读 0赞

使用通知的方式，限制UITextField的输入。  
代码示例如下：

UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(currentView.frame.origin.x, currentView.frame.origin.y + currentView.frame.size.height + 20.0, (self.view.frame.size.width - currentView.frame.origin.x * 2), 44)];
        [self.view addSubview:textField];
        textField.textColor = [UIColor blackColor];
        textField.clearButtonMode = UITextFieldViewModeWhileEditing;
        textField.backgroundColor = [UIColor colorWithWhite:0.5 alpha:0.3];
        textField.keyboardType = UIKeyboardTypeNumberPad;
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textEditChange:) name:UITextFieldTextDidChangeNotification object:textField];

- (void)textEditChange:(NSNotification *)notification
    {
        UITextField *textfield = notification.object;
        NSString *text = textfield.text;
        NSLog(@"1 text = %@, lenght = %@", text, @(text.length));
        
        if (text.length > 0) {
            // 限制11位
            if (text.length > 11) {
                text = [text substringWithRange:NSMakeRange(0, 11)];
            }
            
            // 限制首位为1
            NSString *textFirst = [text substringWithRange:NSMakeRange(0, 1)];
            if ([textFirst isEqualToString:@"1"]) {
                // 限制11位数字
                for (NSInteger index = 0; index < text.length; index++) {
                    NSString *subText = [text substringWithRange:NSMakeRange(index, 1)];
                    if ([@"0123456789" containsString:subText]) {
                        
                    } else {
                        text = [text stringByReplacingOccurrencesOfString:subText withString:@""];
                        index--;
                    }
                }
            } else {
                text = [text stringByReplacingOccurrencesOfString:textFirst withString:@""];
            }
            // 重置输入字符
            textfield.text = text;
        }
        
        text = textfield.text;
        NSLog(@"2 text = %@, lenght = %@", text, @(text.length));
    }