ios - “获取号码来源”按钮不允许输入超过两位数的号码

Question

我正在开发计算器，我使用发件人按钮标签值从按钮中获取号码。用户将无法输入超过两个

文本字段中的数字值
即 34+22 , 23+22 这样他就可以进了,

234+234 这样他就无法在文本字段中输入值。为此我使用

-(IBAction)numberpress:(UIButton *)sender //number select

 {

     NSString *number = sender.currentTitle;
     self.caldisplay.text = [self.caldisplay.text stringByAppendingString:number];
     NSLog(@"%@ number is caldis",self.caldisplay.text);

 }

我该怎么做，帮帮我，谢谢..

Answer 1

尝试

   -(IBAction)numberpress:(UIButton *)sender //number select

{
    NSString *number = sender.currentTitle;
    NSString *calculatingString = nil;
    if (self.caldisplay.text.length >= 2) {
        NSString *lastTwoChar = [self.caldisplay.text substringFromIndex:[self.caldisplay.text length] - 2];
        if ([lastTwoChar integerValue] >= 10) { // last char is content two number
            if ([number integerValue] > 0 || [number isEqualToString:@"0"]) {
                // invalid case. donothing here
                calculatingString = self.caldisplay.text;
            } else {
                calculatingString = [self.caldisplay.text stringByAppendingString:number];
            }
        } else {
            calculatingString = [self.caldisplay.text stringByAppendingString:number];
        }
    } else {
        calculatingString = [self.caldisplay.text stringByAppendingString:number];
    }

    // check valid input
    if ([self calculate:calculatingString] > 100) {
        // invalid case. donothing here
    } else {
        self.caldisplay.text = calculatingString;
    }
    NSLog(@"%@ number is caldis",self.caldisplay.text);
}

- (NSInteger)calculate:(NSString *)input {
    // you need to wite code calculating string here
    // example code to calculate only operator '+'
    NSArray *operands = [input componentsSeparatedByString:@"+"];
    NSInteger result = 0;
    for (NSString *operand in operands) {
        result = result + [operand integerValue];
    }
    return result;
}