可以在UILabel的Category中提供如下幾個方法:

.h文件

@interface UILabel (ChangeLineSpaceAndWordSpace)
/**
 *  改變行間距
 */
+ (void)changeLineSpaceForLabel:(UILabel *)label WithSpace:(float)space;

/**
 *  改變字間距
 */
+ (void)changeWordSpaceForLabel:(UILabel *)label WithSpace:(float)space;

/**
 *  改變行間距和字間距
 */
+ (void)changeSpaceForLabel:(UILabel *)label withLineSpace:(float)lineSpace WordSpace:(float)wordSpace;

@end

.m文件

@implementation UILabel (ChangeLineSpaceAndWordSpace)

+ (void)changeLineSpaceForLabel:(UILabel *)label WithSpace:(float)space {
    
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:space];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
    
}

+ (void)changeWordSpaceForLabel:(UILabel *)label WithSpace:(float)space {
    
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText attributes:@{NSKernAttributeName:@(space)}];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
    
}

+ (void)changeSpaceForLabel:(UILabel *)label withLineSpace:(float)lineSpace WordSpace:(float)wordSpace {
    
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText attributes:@{NSKernAttributeName:@(wordSpace)}];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:lineSpace];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
    
}
@end

附: 在Xcode8中創建Category文件的方法:

在工程目錄中右鍵選擇New File...或者使用鍵盤command+N, 然后在彈出窗口中選擇Objective-C File

新建文件

然后

起名字, 選擇Category, 并選擇要擴展的類

最后

設置好后點擊Next完成