ios交替4种颜色

Question

我试图给 4 个单元格不同的颜色，然后重复它。 (所以不是斑马样式表，而是使用 4)为什么这不起作用？我只有 2 种颜色....

if (indexPath.row % 4 == 0)
    [cell setColor:[UIColor colorFromHexString:@"35a8e1"]];
if (indexPath.row % 4 == 1)
    [cell setColor:[UIColor colorFromHexString:@"5cb14c"]];
if (indexPath.row % 4 == 2)
    [cell setColor:[UIColor colorFromHexString:@"ec292d"]];
else
    [cell setColor:[UIColor colorFromHexString:@"ee8c1d"]];




+(UIColor*)colorFromHexString:(NSString*)hex
{
    NSString *cString = [[hex stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

    // String should be 6 or 8 characters
    if ([cString length] < 6) return [UIColor grayColor];

    // strip 0X if it appears
    if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2];

    if ([cString length] != 6) return  [UIColor grayColor];

    // Separate into r, g, b substrings
    NSRange range;
    range.location = 0;
    range.length = 2;
    NSString *rString = [cString substringWithRange:range];

    range.location = 2;
    NSString *gString = [cString substringWithRange:range];

    range.location = 4;
    NSString *bString = [cString substringWithRange:range];

    // Scan values
    unsigned int r, g, b;
    [[NSScanner scannerWithString:rString] scanHexInt:&r];
    [[NSScanner scannerWithString:gString] scanHexInt:&g];
    [[NSScanner scannerWithString:bString] scanHexInt:&b];

    return [UIColor colorWithRed:((float) r / 255.0f)
                           green:((float) g / 255.0f)
                            blue:((float) b / 255.0f)
                           alpha:1.0f];
}

Answer 1

我将实现以下内容，以便更容易推断出实际发生的情况:

NSUInteger index = indexPath.row;

if (index % 4 == 0) {
    [cell setColor:[UIColor colorFromHexString:@"35a8e1"]];
} else if (index % 4 == 1) {
    [cell setColor:[UIColor colorFromHexString:@"5cb14c"]];
} else if (index % 4 == 2) {
    [cell setColor:[UIColor colorFromHexString:@"ec292d"]];
} else {
    [cell setColor:[UIColor colorFromHexString:@"ee8c1d"]];
}

以这种方式编写时，您的代码将被迫只执行一个单个操作。

此外，我会在第一个 if 语句上设置一个断点，然后单步执行整个语句以查看正在执行的语句。

---

或者，使用 switch 语句可能会使事情变得更清晰:

 switch (indexPath.row % 4) {
 case 0:
      [cell setColor:[UIColor colorFromHexString:@"35a8e1"]];
      break;
 case 1:
      [cell setColor:[UIColor colorFromHexString:@"5cb14c"]];
      break;
 case 2:
      [cell setColor:[UIColor colorFromHexString:@"ec292d"]];
      break;
 case 3:
      [cell setColor:[UIColor colorFromHexString:@"ee8c1d"]];
      break;
}