iOS label 的故事

UIlabel   继承与UIView 实现了 NSCoding 协议    主要的作用是用于在手机界面上展示一些内容 （标签作用）

m_label = [UILabel new];//创建一个label
    
    //设置label在手机坐标系中位置和大小
    m_label.frame = CGRectMake(10, 40, WIDTH - 20, 40);
    
    //设置label中展示的内容
    m_label.text = @"12345ytrewq";
    
    //设置label中文字的对齐方式
    m_label.textAlignment = NSTextAlignmentCenter;
    
    //设置文字的颜色
    m_label.textColor = [UIColor redColor];
    
    //设置label的背景颜色
    m_label.backgroundColor = [UIColor lightGrayColor];
    
    //设置文字 字体和字号
    m_label.font = [UIFont systemFontOfSize:14];
    
    
    //设置label圆角
    m_label.layer.borderColor = [[UIColor greenColor] CGColor];
    m_label.layer.cornerRadius = 8.0f;
    m_label.clipsToBounds = YES;
    m_label.layer.masksToBounds = YES;
    
    
    /*
     //设置高亮
     label.highlighted = YES;
     label.highlightedTextColor = [UIColor orangeColor];
     
     //设置阴影
     label.shadowColor = [UIColor redColor];
     label.shadowOffset = CGSizeMake(1.0,1.0);
     
     //设置是否能与用户进行交互
     label.userInteractionEnabled = YES;
     
     //设置label中的文字是否可变，默认值是YES
     label.enabled = NO;
     
     //如果adjustsFontSizeToFitWidth属性设置为YES，这个属性就来控制文本基线的行为
     label4.baselineAdjustment = UIBaselineAdjustmentNone;
     */
    
    [self.view addSubview:m_label];

UILabel 的一些高级用法  在一个label中展示出不同颜色不同字号不同字体的文字

/************** label的高级用法 *************/
    //label中出现多种颜色的和不同字体的文字
    NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:@"Using NSAttributed String"];
    
    [str addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(0,5)];
    [str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(6,12)];
    [str addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(19,6)];
    
    
    [str addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Arial-BoldItalicMT" size:14.0] range:NSMakeRange(0, 5)];
    [str addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"HelveticaNeue-Bold" size:24.0] range:NSMakeRange(6, 12)];
    [str addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"Courier-BoldOblique" size:14.0] range:NSMakeRange(19, 6)];
    
    UILabel *label1 = [UILabel new];
    label1.frame = CGRectMake(10, 100, WIDTH - 20, 40);
    label1.backgroundColor = [UIColor lightGrayColor];
    label1.attributedText = str;
    label1.textAlignment = NSTextAlignmentCenter;
    [self.view addSubview:label1];

UILabel 的高度自动调整来适应其中的文字内容

 UILabel *lab = [self.view viewWithTag:1000];
    if (!lab)
    {
        lab = [UILabel new];
        lab.text = _textfield.text;
        lab.font = [UIFont systemFontOfSize:14];
        lab.textColor = [UIColor blackColor];
        lab.backgroundColor = [UIColor orangeColor];
        lab.numberOfLines = 0;
        lab.lineBreakMode = NSLineBreakByCharWrapping;
        [self.view addSubview:lab];
    }
    //通过文字的多少来  让lab的高度自动调整
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
    CGRect rect = [_textfield.text boundingRectWithSize:CGSizeMake(200, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14],NSParagraphStyleAttributeName:paragraphStyle} context:nil];
    
   lab.frame = CGRectMake(50, self.textfield.frame.origin.y + 60, rect.size.width , rect.size.height);