相关疑难解决方法(0)

我试图在标签上添加一些花哨的文本,但是我遇到了NSMutableAttributedString类的一些问题.我试图实现四个:1.更改字体,2.下划线范围,3.更改范围颜色,4.上标范围.

这段代码:

- (void)applicationDidFinishLaunching:(NSNotification*)aNotification
{
    NSMutableAttributedString* display = [[NSMutableAttributedString alloc]
                                          initWithString:@"Hello world!"];
    NSUInteger length = [[display string]length] - 1;

    NSRange wholeRange = NSMakeRange(0, length);
    NSRange helloRange = NSMakeRange(0, 4);
    NSRange worldRange = NSMakeRange(6, length);

    NSFont* monoSpaced = [NSFont fontWithName:@"Menlo" 
                                         size:22.0];

    [display addAttribute:NSFontAttributeName
                    value:monoSpaced
                    range:wholeRange];

    [display addAttribute:NSUnderlineStyleAttributeName 
                    value:[NSNumber numberWithInt:1] 
                    range:helloRange];

    [display addAttribute:NSForegroundColorAttributeName 
                    value:[NSColor greenColor]
                    range:helloRange];

    [display addAttribute:NSSuperscriptAttributeName 
                    value:[NSNumber numberWithInt:1] 
                    range:worldRange];

    //@synthesize textLabel; is in this file.
    [textLabel setAttributedStringValue:display];
}

给我这个错误:

NSMutableRLEArray objectAtIndex:effectiveRange:: Out of bounds

此外,我尝试搞乱范围,但当我尝试时变得更加困惑NSRange worldRange = NSMakeRange(4, 5); …