测试一，只改变numberOfLines属性，label的高度不会自适应(会有text中的一部分内容称为......)

    NSString *str = @"jgreijgirjeirgjierjgiu4t9eumctuv5 vtmnvghvmc5v5tgh58tc857y";

    UILabel *label  = [[UILabel alloc]initWithFrame:CGRectMake(, , , )];

    label.font = [UIFont systemFontOfSize:];

    label.backgroundColor = [UIColor cyanColor];

    label.numberOfLines = ;

    label.text = str;

    NSLog(@"label1.frame = %@",NSStringFromCGRect(label.frame));

    [self.view addSubview:label];

    测试二，如果加上numberOfLines属性和[label1 sizeToFit]这句话，label的高度会根据你设置的宽度自适应，自己最开始设置的fram的高度会失效,,,注意注意：其实他的宽度和你的设置也有一定的偏差

    UILabel *label1  = [[UILabel alloc]initWithFrame:CGRectMake( ,, , )];

    label1.font = [UIFont systemFontOfSize:];

    label1.backgroundColor = [UIColor cyanColor];

    label1.numberOfLines = ;

    label1.text = str;

    [label1 sizeToFit];

    NSLog(@"label1.frame = %@",NSStringFromCGRect(label1.frame));

    [self.view addSubview:label1];

    测试三：用老师封装的类（Category）中的方法（autolayoutContent：origin：FontFloat：contentWidth：），不用设置numberOfLines属性和[label1 sizeToFit]方法，，，但设置的contentWidth：宽度和真实的是有一点偏差的

    UILabel *label2  = [[UILabel alloc]initWithFrame:CGRectMake( , , , )];

   // label2.font = [UIFont systemFontOfSize:15];

    label2.backgroundColor = [UIColor blueColor];

    label2.text = str;

    [label2 autolayoutContent:str origin:CGPointMake(, ) FontFloat: contentWidth:];

    NSLog(@"label2.frame = %@",NSStringFromCGRect(label2.frame));

    [self.view addSubview:label2];

    测试四：label自适应高度的非主流方法(用到numberOfLines和sizeThatFits：方法)，，优点：宽度精准

    UILabel *label3 = [[UILabel alloc]initWithFrame:CGRectMake(, , , )];

    label3.font = [UIFont systemFontOfSize:];

    label3.backgroundColor = [UIColor yellowColor];

    label3.numberOfLines = ;

    label3.text = str;

    //label3.lineBreakMode = NSLineBreakByWordWrapping;//(默认)

    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];