推薦第二個

測試一，只改變numberOfLines屬性，label的高度不會自適應(會有text中的一部分內容稱為......)
    NSString *str = @"jgreijgirjeirgjierjgiu4t9eumctuv5 vtmnvghvmc5v5tgh58tc857y";
    UILabel *label  = [[UILabel alloc]initWithFrame:CGRectMake(50, 50, 100, 100)];
    label.font = [UIFont systemFontOfSize:15];
    label.backgroundColor 
 
= [UIColor cyanColor];
    label.numberOfLines = 0;
    label.text = str;
    NSLog(@"label1.frame = %@",NSStringFromCGRect(label.frame));
    [self.view addSubview:label];

    
    測試二，如果加上numberOfLines屬性和[label1 sizeToFit]這句話，label的高度會根據你設置的寬度自適應，自己最開始設置的fram的高度會失效,,,註意註意：其實他的寬度和你的設置也有一定的偏差
    UILabel 
 
*label1  = [[UILabel alloc]initWithFrame:CGRectMake(100 ,150, 100, 0)];
    label1.font = [UIFont systemFontOfSize:15];
    label1.backgroundColor = [UIColor cyanColor];
    label1.numberOfLines = 0;
    label1.text = str;
    [label1 sizeToFit];
    NSLog(@"label1.frame = %@",NSStringFromCGRect(label1.frame));
    [self.view addSubview:label1];
    
    
    測試三：用老師封裝的類（Category）中的方法（autolayoutContent：origin：FontFloat：contentWidth：），不用設置numberOfLines屬性和[label1 sizeToFit]方法，，，但設置的contentWidth：寬度和真實的是有一點偏差的
    UILabel 
 
*label2  = [[UILabel alloc]initWithFrame:CGRectMake(100 , 300, 100, 0)];
   // label2.font = [UIFont systemFontOfSize:15];
    label2.backgroundColor = [UIColor blueColor];
    label2.text = str;
    [label2 autolayoutContent:str origin:CGPointMake(100, 300) FontFloat:30 contentWidth:150];
    NSLog(@"label2.frame = %@",NSStringFromCGRect(label2.frame));
    [self.view addSubview:label2];
    
    
    測試四：label自適應高度的非主流方法(用到numberOfLines和sizeThatFits：方法)，，優點：寬度精準
    UILabel *label3 = [[UILabel alloc]initWithFrame:CGRectMake(150, 50, 150, 0)];
    label3.font = [UIFont systemFontOfSize:15];
    label3.backgroundColor = [UIColor yellowColor];
    label3.numberOfLines = 0;
    label3.text = str;
    //label3.lineBreakMode = NSLineBreakByWordWrapping;//(默認)
    CGSize size = [label3 sizeThatFits:CGSizeMake(label3.frame.size.width, MAXFLOAT)];
    label3.frame = CGRectMake(label3.frame.origin.x, label3.frame.origin.y, label3.frame.size.width,            size.height);
    NSLog(@"label3.frame = %@",NSStringFromCGRect(label3.frame));
    [self.view addSubview:label3];

iOS Label 自適應高度