1、由于label控件没有contentInsets属性，需要自定义label，添加Insets 属性，并重写父类的几个方法
//下面四个方法用来初始化edgeInsets
- (instancetype)init {
if (self = [super init]) {
self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);
}
return self;
}
- (instancetype)initWithFrame:(CGRect)frame
{
if(self = [super initWithFrame:frame])
{
self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);
}
return self;
}
//storyboard使用
- (instancetype)initWithCoder:(NSCoder *)aDecoder
{
if (self = [super initWithCoder:aDecoder]) {
self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);
}
return self;
}
//xib使用
- (void)awakeFromNib
{
[super awakeFromNib];
self.edgeInsets = UIEdgeInsetsMake(10, 0, 10, 0);
}
// 修改绘制文字的区域，edgeInsets增加bounds
-(CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines
{
//设置第一行和最后一行距离label的距离
CGRect rect = [super textRectForBounds:UIEdgeInsetsInsetRect(bounds,self.edgeInsets) limitedToNumberOfLines:numberOfLines];
//根据edgeInsets，修改绘制文字的bounds
rect.origin.x -= self.edgeInsets.left;
rect.origin.y -= self.edgeInsets.top;
rect.size.width += self.edgeInsets.left + self.edgeInsets.right;
rect.size.height += self.edgeInsets.top + self.edgeInsets.bottom;
return rect;
}
//绘制文字
- (void)drawTextInRect:(CGRect)rect
{
//令绘制区域为原始区域，增加的内边距区域不绘制
[super drawTextInRect:UIEdgeInsetsInsetRect(rect, self.edgeInsets)];
}
2、label控件显示多行文本，需要设置numberOfLines设置为0，还要自适用高度
//第一种方法：
self.label.adjustsFontSizeToFitWidth=YES;
//第二种方法：(废弃API)
CGFloat fontSizeToFits;
[self.label.text sizeWithFont:self.label.font minFontSize:12.0 actualFontSize:&fontSizeToFits forWidth:self.label.bounds.size.width lineBreakMode:NSLineBreakByWordWrapping];//12是最小字体
self.label.font = [self.label.font fontWithSize:fontSizeToFits];
//第三种方法：
CGSize labelSize = [self.text boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width - 20, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14]} context:nil].size;
self.label.frame = CGRectMake(0, 0, labelSize.width, labelSize.height);
