1. 技术文章
  2. Dynamic Height Issue for UITableView Cells (Swift)

Dynamic Height Issue for UITableView Cells (Swift)

由 放肆的年华 提交于 2019-11-26 09:18:47

问题


Dynamic text of variable length are being injected into tableview cell labels. In order for the tableview cells\' heights to be dynamically sized, I have implemented in viewDidLoad():

self.tableView.estimatedRowHeight = 88.0
self.tableView.rowHeight = UITableViewAutomaticDimension

This works nicely for the cells that have yet to be scrolled to (as UITableViewAutomaticDimention is called upon scrolling to the cell), but not for the cells that are initially rendered onscreen upon loading the table with data.

I have tried simply reloading the data (as suggested in many other resources):

self.tableView.reloadData()

in both viewDidAppear() and viewWillAppear() and it was to no avail. I am lost.. does anyone know how to have xcode render the dynamic height for the cells loaded initially on screen?

Please let me know, if there is a better alternate method.


回答1:


Try This:

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

EDIT

func tableView(tableView: UITableView, estimatedHeightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

Swift 4

func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

Swift 4.2

func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableView.automaticDimension
}

Define above Both Methods.
It solves the problem.

PS: Top and bottom constraints is required for this to work.

Here is example




回答2:


Use this:

tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 300

and don't use: heightForRowAtIndexPath delegate function

Also, in the story board don't set the height of the label that contains a large amount of data. Give it top, bottom, leading, trailing constraints.




回答3:


SWIFT 3

tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 160

AND!!! In storyBoard: You HAVE TO set TOP & BOTTOM constraints for your Label. Nothing else.




回答4:


This strange bug was solved through Interface Builder parameters as the other answers did not resolve the issue.

All I did was make the default label size larger than the content potentially could be and have it reflected in the estimatedRowHeight height too. Previously, I set the default row height in Interface Builder to 88px and reflected it like so in my controller viewDidLoad():

self.tableView.rowHeight = UITableViewAutomaticDimension
self.tableView.estimatedRowHeight = 88.0

But that didn't work. So I realized that content wouldn't ever become larger than maybe 100px, so I set the default cell height to 108px (larger than the potential content) and reflected it like so in the controller viewDidLoad():

self.tableView.rowHeight = UITableViewAutomaticDimension
self.tableView.estimatedRowHeight = 108.0

This actually allowed the code to shrink down the initial labels to the correct size. In other words, it never expanded out to a larger size, but could always shrink down... Also, no additional self.tableView.reloadData() was needed in viewWillAppear().

I know this does not cover highly variable content sizes, but this worked in my situation where the content had a maximum possible character count.

Not sure if this is a bug in Swift or Interface Builder but it works like a charm. Give it a try!




回答5:


Set automatic dimension for row height & estimated row height and ensure following steps:

@IBOutlet weak var table: UITableView!

override func viewDidLoad() {
    super.viewDidLoad()

    // Set automatic dimensions for row height
    // Swift 4.2 onwards
    table.rowHeight = UITableView.automaticDimension
    table.estimatedRowHeight = UITableView.automaticDimension


    // Swift 4.1 and below
    table.rowHeight = UITableViewAutomaticDimension
    table.estimatedRowHeight = UITableViewAutomaticDimension

}



// UITableViewAutomaticDimension calculates height of label contents/text
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    // Swift 4.2 onwards
    return UITableView.automaticDimension

    // Swift 4.1 and below
    return UITableViewAutomaticDimension
}

For Example: if you have a label in your UITableviewCell then,

  • Set number of lines = 0 (& line break mode = truncate tail)
  • Set all constraints (top, bottom, right left) with respect to its superview/ cell container.
  • Optional: Set minimum height for label, if you want minimum vertical area covered by label, even if there is no data.

Here is sample label with dynamic height constraints.




回答6:


Dynamic sizing cell of UITableView required 2 things

  1. Setting the the right constraint of your view inside the table view cell (mostly it includes giving your view proper top , bottom and traling constraints)

  2. Calling these properties of TableView in viewDidLoad()

     tableView.rowHeight = UITableViewAutomaticDimension

 tableView.estimatedRowHeight = 140

This is a wonderfull tutorial on self-sizing (dynamic table view cells) written in swift 3 .




回答7:


For Swift 3 you can use the following:

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}



回答8:


Try

override func viewWillAppear(animated: Bool) {
    self.tableView.layoutSubviews()
}

I had the same problem and it works for me.




回答9:


To make autoresizing of UITableViewCell to work make sure you are doing these changes :

  • In Storyboard your UITableView should only contain Dynamic Prototype Cells (It shouldn't use static cells) otherwise autoresizing won't work.
  • In Storyboard your UITableViewCell's UILabel has configured for all 4 constraints that is top, bottom, leading and trailing constraints.
  • In Storyboard your UITableViewCell's UILabel's number of lines should be 0

  • In your UIViewController's viewDidLoad function set below UITableView Properties :

    self.tableView.estimatedRowHeight = <minimum cell height> 
self.tableView.rowHeight = UITableViewAutomaticDimension



回答10:


For Swift 4.2

@IBOutlet weak var tableVw: UITableView!

override func viewDidLoad() {
    super.viewDidLoad()

    // Set self as tableView delegate
    tableVw.delegate = self

    tableVw.rowHeight = UITableView.automaticDimension
    tableVw.estimatedRowHeight = UITableView.automaticDimension
}

// UITableViewDelegate Method 
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

    return UITableView.automaticDimension
}

Happy Coding :)




回答11:


I was just inspired by your solution and tried another way.

Please try to add tableView.reloadData() to viewDidAppear().

This works for me.

I think the things behind scrolling is "the same" as reloadData. When you scroll the screen, it's like calling reloadData() when viewDidAppear .

If this works, plz reply this answer so I could be sure of this solution.




回答12:


For Swift i checked this answer in iOS 9.0 and iOS 11 also (Xcode 9.3)

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

func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

Here you need to add top, bottom, right and left constraints




回答13:


Unfortunately, I am not sure what I was missing. The above methods don't work for me to get the xib cell's height or let the layoutifneeded()or UITableView.automaticDimension to do the height calculation. I've been searching and trying for 3 to 4 nights but could not find an answer. Some answers here or on another post did give me hints for the workaround though. It's a stupid method but it works. Just add all your cells into an Array. And then set the outlet of each of your height constraint in the xib storyboard. Finally, add them up in the heightForRowAt method. It's just straight forward if you are not familiar with the those APIs.

Swift 4.2

CustomCell.Swift

@IBOutlet weak var textViewOneHeight: NSLayoutConstraint!
@IBOutlet weak var textViewTwoHeight: NSLayoutConstraint!
@IBOutlet weak var textViewThreeHeight: NSLayoutConstraint!

@IBOutlet weak var textViewFourHeight: NSLayoutConstraint!
@IBOutlet weak var textViewFiveHeight: NSLayoutConstraint!

MyTableViewVC.Swift

.
.
var myCustomCells:[CustomCell] = []
.
.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = Bundle.main.loadNibNamed("CustomCell", owner: self, options: nil)?.first as! CustomCell

.
.
myCustomCells.append(cell)
return cell

}


override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

   let totalHeight = myCustomCells[indexPath.row].textViewOneHeight.constant + myCustomCells[indexPath.row].textViewTwoHeight.constant +  myCustomCells[indexPath.row].textViewThreeHeight.constant + myCustomCells[indexPath.row].textViewFourHeight.constant + myCustomCells[indexPath.row].textViewFiveHeight.constant

  return totalHeight + 40 //some magic number


}



回答14:


I use these

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

    return 100
}



回答15:


In my case - In storyboard i had a two labels as in image below, both labels was having desired width values been set before i made it equal. once you unselect, it will change to automatic, and as usual having below things should work like charm.

1.rowHeight = UITableView.automaticDimension, and
2.estimatedRowHeight = 100(In my case).
3.make sure label number of lines is zero.




回答16:


You should just set all constraints for TOP, BOTTOM and HEIGHT for each object on cell view/views and remove exists middle Y position if have. Because where you didn't this, puts artifacts on another views.




回答17:


For objective c this is one of my nice solution. it's worked for me.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    cell.textLabel.text = [_nameArray objectAtIndex:indexPath.row];
    cell.textLabel.numberOfLines = 0;
    cell.textLabel.lineBreakMode = NSLineBreakByWordWrapping;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    return UITableViewAutomaticDimension;
}

We need to apply these 2 changes.

1)cell.textLabel.numberOfLines = 0;
  cell.textLabel.lineBreakMode = NSLineBreakByWordWrapping;

2)return UITableViewAutomaticDimension;



回答18:


I had also got this issue initially, I had resolved my issue from this code try avoiding the use of self.tableView.reloadData() instead of this code for dynamic height

[self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationFade];



回答19:


In addition to what others have said,

SET YOUR LABEL'S CONSTRAINTS RELATIVE TO THE SUPERVIEW!

So instead of placing your label's constraints relative to other things around it, constrain it to the table view cell's content view.

Then, make sure your label's height is set to more than or equal 0, and the number of lines is set to 0.

Then in ViewDidLoad add:

tableView.estimatedRowHeight = 695

tableView.rowHeight = UITableViewAutomaticDimension



回答20:


When using a static UITableView, I set all the values in the UILabels and then call tableView.reloadData().




回答21:


This is simple when doing 2 things:

  1. setting the automatic heigtht

    tableView.rowHeight = UITableView.automaticDimension

  2. creating all TableViewCells with FULL constraints from top to bottom. The last element **MUST ** define some bottom spacing to end the cell.

So the layout engine can compute the cell heigth and apply the value correctly.




回答22:


self.tableView.rowHeight = UITableViewAutomaticDimension
self.tableView.estimatedRowHeight = 88.0

And don't forget to add botton constraints for label




回答23:


self.Itemtableview.estimatedRowHeight = 0;
self.Itemtableview.estimatedSectionHeaderHeight = 0;
self.Itemtableview.estimatedSectionFooterHeight = 0;


[ self.Itemtableview reloadData];
self.Itemtableview.frame = CGRectMake( self.Itemtableview.frame.origin.x,  self.Itemtableview.frame.origin.y,  self.Itemtableview.frame.size.width,self.Itemtableview.contentSize.height + self.Itemtableview.contentInset.bottom + self.Itemtableview.contentInset.top);



回答24:


Set proper constraint and update delegate methods as:

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}
func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
    return UITableViewAutomaticDimension
}

This will resolve dynamic cell height issue. IF not you need to check constraints.



来源：https://stackoverflow.com/questions/30494702/dynamic-height-issue-for-uitableview-cells-swift

标签
ios
swift
xcode
uitableview
row-height
易学教程内所有资源均来自网络或用户发布的内容，如有违反法律规定的内容欢迎反馈！
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!