其实只需要一句话：label.numberOfLines=0;
UILabel *tipLabel = [[UILabel alloc] init];
tipLabel.textAlignment = NSTextAlignmentLeft;
tipLabel.backgroundColor = [UIColor clearColor];
tipLabel.font= [UIFontfontWithName:font_yuantisize:20];
tipLabel.text = @"欢迎光临，我的朋友们，这里是“凌冬将至，夕阳已沉”的胡言乱语";
NSDictionary *attribute = @{NSFontAttributeName: [UIFont fontWithName:font_yuanti size:20]};
CGSize labelSize = [tipLabel.text boundingRectWithSize:CGSizeMake(200, 5000) options: NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:attribute context:nil].size;
tipLabel.frame = CGRectMake(33, CGRectGetHeight(self.view.frame)/2.0-SafeAreaTopHeight*2, CGRectGetWidth(self.view.frame)-66, labelSize.height);
tipLabel.numberOfLines=0;
tipLabel.textColor= [UIColorcolorWithHexString:@"#000000"];
[_tableViewaddSubview:tipLabel];
