UILabel 自动换行 和支持换行符

主要添加_notHintLabel.numberOfLines = 0;  允许换行

    NSString *str =  @"温馨提示:该主人未通过平台认证,不可线上\n交易";CGSize size = [str sizeWithFont:[UIFont systemFontOfSize:17] constrainedToSize:CGSizeMake(DEVICEWIDTH,10000.0f)lineBreakMode:UILineBreakModeWordWrap];_notHintLabel = [self generateLabel:17.0];_notHintLabel.frame = CGRectMake(15, DEVICEHEIGHT-70-size.height, size.width, size.height);_notHintLabel.text = str;_notHintLabel.textColor = 999999;_notHintLabel.hidden = YES;_notHintLabel.numberOfLines = 0;[self.view addSubview:_notHintLabel];