iOS长度不同可自动换行的标签

• 写到一个类似新闻多图详情的页面,下方需要根据服务器返回的值绘制不定数量的标签.字符长度也不尽相同.需要进行动态计算长度和位置.

绘制可以实现自动换行的label/button

• tagView就是放置buttons的view
  #pragma mark - 尝试绘制自动换行的类型标签label/button

    - (void)createTypeBtnsView{
  
    tagView = [[UIView alloc]initWithFrame:CGRectMake(10, 45 + 300*self.model.imagesArray.count, [DMDevceManager screenWidth]-20, 10)];
    CGFloat positionX = 0.0;
    CGFloat positionY = 0.0;
    CGFloat bgViewWidth = [DMDevceManager screenWidth]-20;
    UIFont *btnTitleFont = [UIFont systemFontOfSize:13];
  
    //如果有图片作为边框,使用注释
    //    UIImage *selImage = [UIImage imageNamed:@"greenCir1"];
    //    UIImage *norImage = [UIImage imageNamed:@"grayCir2"];
  
    //    CGFloat left = selImage.size.width/4;
     //    CGFloat top = selImage.size.height/4;
  
    for(int i = 0;i<self.model.typesArray.count;i++)
    {
  //下面的方法
    CGFloat btnWidth = [DMUtils textWidth:self.model.typesArray[i] Font:btnTitleFont height:25];
     
    if(positionX + btnWidth > bgViewWidth){
        positionX = 0;
        positionY += 30;
    }
     
    UIButton *btn = [DMUITool createButtonWithFrame:CGRectMake(positionX, positionY, btnWidth, 25) title:self.model.typesArray[i] target:self action:@selector(typeBtnClick:) tag:i+30000];
    btn.titleLabel.font = btnTitleFont;
     
    btn.backgroundColor = Color(103, 206, 249);
    btn.layer.masksToBounds = YES;
    btn.userInteractionEnabled = YES;
    btn.layer.cornerRadius = 12;
    [btn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
  
    positionX += (btnWidth+5);
    //如果有图片作为边框,从4分之1处拉伸,承接上一个注释
    //        [btn setBackgroundImage:[selImage stretchableImageWithLeftCapWidth:left topCapHeight:top] forState:UIControlStateSelected];
    //        [btn setBackgroundImage:[norImage stretchableImageWithLeftCapWidth:left topCapHeight:top] forState:UIControlStateNormal];  
    [tagView addSubview:btn];      
    }
  

下面的方法是来计算每个label上文字所占宽度

    /*
     *获取文字所占宽度
     *@param text 文本内容，计算式包括了换行空格等
     *@param font 字体
     *@param height:指定高度下计算，若不设限使用CGFLOAT_MAX
     */
    + (CGFloat)textWidth:(NSString *)text Font:(UIFont *)font height:(CGFloat)height
    {
    if(![DMDevceManager isiOS7])
   {
     return [text sizeWithFont:font constrainedToSize:CGSizeMake(MAXFLOAT, height) lineBreakMode:NSLineBreakByCharWrapping].width;    
   }
    else{ 
    if(text.length <= 0)
   {
        return 0;
    }     
    UITextView *textView = APPDELEGATE.textView;
    textView.text = text;
    textView.font = font;
    CGSize size = [textView sizeThatFits:CGSizeMake(CGFLOAT_MAX, height)];
    return size.width;
      }
    }

效果如图:

可自动换行的buttons