ios7自动布局tableViewCell

Question

I currently have a custom UITableViewCell with a number of labels in it. Not all of those labels will necessarily have a value but they could do - and they may be multiline (At least 2 labels will always be visible). If there isn't any text then the label should collapse. What I'm trying to achieve is that each label only takes up the height it needs and they all butt up to each other. I've got all of this working, except I finally want a bottom margin of 11 between the last label and the cells content view with the cell height adjusted accordingly. This is the only bit where I can't seem to get my constraints working correctly.

I correctly return the right height by creating a dummy cell, and in my cellForRowAtIndexPath method I try to set the cell and the cell's contentview frame accordingly. But the cell height that is rendered on the screen is always the same as it was defined in the xib.

I know there's a lack of code here, but all my constraints have been define in IB and each label has a trailing and leading space for with and a top space of 0 to the label above it. The top label has a top space to create a top margin to the content view, but as soon as I do this on the bottom label it stretches the height of the labels to accommodate all the constraints .

I've seen various tutorials and questions on here that relate to 2 labels where 1 might be a variable size, but I haven't been able to adapt any solutions for what I'm trying to achieve.

Answer 1

Okay,

1. Get as many labels you want (suppose you want 2 labels inside the cell,) Create 2 labels with height 1 in storyboard, or if you are programmatically adding them, then you can do.

    UILabel *myLabel1 = [[UILabel alloc]initWithFrame:[CGRectMake:(x,y,width,1)]; // assuming you know their x,y and width respectively as you need them. 

2. Now add constraints to the labels (Be sure you make them ambiguous or else orientation would mess it up, ):

   3 a. Height -(should be equalto OR greater than => 1). b. Width - [Set it a width],Make sure it has a priority more than others but less than height c. Pin to trailing and leading space, as well as superview top and bottom. d. If there are two Labels make sure you click both of them and add a Vertical or horizontal space according to your needs.

   I think that would make it ambiguous. (I am telling these as you wrote its about autolayout, so despite of orientation this would never get any layout problems).

   Add a snippet that would calculate the height of the Label when you know the string.

     CGSize constrainedSizeOfMessege = CGSizeMake(widthOfLabel, 9999);//150,180 anything you like NSDictionary *attributesDictionaryMessege = [NSDictionary dictionaryWithObjectsAndKeys: [UIFont fontWithName:@"System Italics" size:16.0], NSFontAttributeName, nil]; NSMutableString *myString = [[NSMutableString alloc]initWithString:[[friendsInstanceArray objectAtIndex:indexPath.row] myString] attributes: attributesDictionaryMessege]; CGRect requiredHeightMessege = [myString boundingRectWithSize:constrainedSizeOfMessege options:NSStringDrawingUsesLineFragmentOrigin context:nil]; 

Add the above code in

• (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

Now, calculate the height of the Cell, the height of all the labels if they are 1 height then Return the height of the Cell in storyboard + height of the Expected Label Size.

So The method would look like.

  - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath  {
  CGSize constrainedSizeOfMessege = CGSizeMake(widthOfLabel, 9999);//150,180 anything you like
      NSDictionary *attributesDictionaryMessege = [NSDictionary dictionaryWithObjectsAndKeys:
        [UIFont fontWithName:@"System Italics" size:16.0], NSFontAttributeName,
    nil]; 
       NSMutableString *myString = [[NSMutableString alloc]initWithString:[[friendsInstanceArray objectAtIndex:indexPath.row] myString] attributes: attributesDictionaryMessege];
     CGRect requiredHeightMessege = [myString boundingRectWithSize:constrainedSizeOfMessege options:NSStringDrawingUsesLineFragmentOrigin context:nil];
  int heightOfMessege = requiredHeightMessege.size.height;
       //if cell height is 50 then return 50+heightOfMessege
 return 50+heightOfMessege;
}

And YES POSITIVELY set, mylabel.numberOfLines = 0;

Hope this helps you out

Answer 2

如果您想将标签粘贴在包括空白在内的位置上，请在标签的标题文本中留出一个空格，这不会使他们的文本为空，然后标签会粘贴在位置上。