UILabel 动态计算高度

UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0,0,0,0)];
//设置自动行数与字符换行，为0标示无限制
    [label setNumberOfLines:0];
    label.lineBreakMode = NSLineBreakByWordWrapping;//换行方式
    NSString *strTest = @"用中问和英文 混合测试! just test, good luck!! 看看行不行";

    UIFont *font = [UIFont fontWithName:@"Arial" size:12];
    label.font = font;

    CGSize size = CGSizeMake(LableWight,CGFLOAT_MAX);//LableWight标签宽度，固定的

//计算实际frame大小，并将label的frame变成实际大小

 CGSize labelsize = [strTest sizeWithFont:font constrainedToSize:size lineBreakMode:label.lineBreakMode]; 
label.frame = CGRectMake(0,0, labelsize.width, labelsize.height); label.text = strTest; [self.view addSubview:label];