Expanding tableviewcell based on UIlabel line count

Question

I have a custom UITableViewCell with a UILabel that has multiple lines. I'm trying to implement a tap expand/contract feature so that when the label is only one line, no expansion happens when you tap the cell, but if the label is multiple lines, the cell is capable on expanding/contracting when tapped. I got the expansion and contracting working, but I can't figure out how to make it work based on the number of lines in the UILabel.

This is currently what I'm doing for the cell expansion, but its not based on the UILabel at all.

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

    if (indexPath.row == self.selectedRow?.row && self.expand == true)
    {
        self.previousRow = self.selectedRow?.row
        return 200 
    }
    else if(self.previousRow == self.selectedRow?.row && self.expand == false){
        return 65
    }      
    return 65
}

Since you have custom cell item, then add tap gesture recognition to your label, then when user tap on the item, it will check the condition, if condition matches ,then either expands or contracts. — casillas, Dec 14 '15 at 17:55
You could also check how many lines in the label, check this thread http://stackoverflow.com/questions/4172615/how-to-find-uilabels-number-of-lines — casillas, Dec 14 '15 at 17:57
@casillas I like the gesture recognition option, but it might not be intuitive enough. I'm not using `didSelecRowAtIndexPath` for anything, so I might as well use it for this. I looked through the link you provided, but since this is a tableviewcell, where should I access the cells label size? Doesn't make sense to do it in cellForRowAtIndexPath, right? — Brosef, Dec 14 '15 at 18:07

score 7 · Accepted Answer · answered Dec 15 '15 at 08:03

You can use table view dynamic cell sizing with autolayout in conjunction with the numberOfLines property of UILabel to expand and compress cell.

The heart of the solution is this:

tableView.beginUpdates()
label.numberOfLines = label.numberOfLines == 0 ? 1 : 0
tableView.endUpdates()

This is essentially triggering an animation on the table and toggling the number of lines from 0 (any number of lines) to 1 line. Autolayout is doing the rest.

I think this is better than updating height metrics manually. The full example project can be found on my github: https://github.com/rayfix/MultilineDemo

This did the job. Such an elegant solution. – Brosef Dec 16 '15 at 02:23 — Brosef, Dec 16 '15 at 02:23

score 0 · Answer 2 · answered Dec 14 '15 at 17:39

0

You probably need to measure the text yourself because the label won't have more lines until you expand.

Something like this (the 100000 just needs to be a big number)

CGSize textSize = [self.label.text sizeWithFont:self.label.font constrainedToSize:CGSizeMake(self.label.bounds.width, 100000) lineBreakMode: UILineBreakModeWordWrap];

answered Dec 14 '15 at 17:39

Lou Franco

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Would you do this in cellForRowAtIndexPath? – Brosef Dec 14 '15 at 17:53
FLT_MAX can be used here – Muhammad Zohaib Ehsan Dec 14 '15 at 18:04
I would do it in `heightForRowAtIndexPath`. Perhaps you need to not use the label in that case. Hopefully you know the text, width, and font. – Lou Franco Dec 14 '15 at 19:44
@LouFranco I can store the labels width from `cellForRowAtIndexPath` and access it in in `heightForRowAtIndexPath`. But no idea, how to determine the text size once I'm in `heightForRowAtIndexPath` – Brosef Dec 14 '15 at 20:18
Why can't you use `sizeWithFont:constrainedToSize:lineBreakMode:` as I showed above? – Lou Franco Dec 15 '15 at 01:32

Expanding tableviewcell based on UIlabel line count

2 Answers2