public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "approve_cell");
let event = self.events[indexPath.row];
cell.textLabel?.text = event.name;
return cell;
}
I placed 2 images and a label in tableviewcell. When i run the app, images are not visible. What could be the reason?
Check that you are not using the basic style of the UITableViewCell because if you are then that style only includes labels.. no image views. Change it to subtitle or one of the details.
For reference, see: https://developer.apple.com/library/content/documentation/UserExperience/Conceptual/TableView_iPhone/TableViewCells/TableViewCells.html
You probably forgot to set AutoLayoutConstraints of your image view. You could either add constraints to that image view through storyboard or through code. The other method is setting the frame of your image view in -(void)viewDidLayoutSubviews, because when you're using auto-layout, the layout of those views will be undefined if its constraints doesn't fulfill system's computing need. So you should either set right constraints or give a specific frame to those undefined views after all of the others has-constraints-views are arranged.
You creat cell in storyboard but you never use this cell created from storyboard. instead you manually creat it by UITableViewCell's designated initializer without override layout method of it.
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "approve_cell", for: indexPath)
let event = self.events[indexPath.row];
cell.textLabel?.text = event.name;
return cell;
}
You need to set either Autolayout or used Autoresizing. For autolayout just pinned the proper leading, trailing, top and bottom constraint.
Related
I have a very similar question as posted here (Dynamic UIImageView Size Within UITableView) where I'm trying to dynamically retrieve an image from Firebase and make the resulting tableview adjust to the height of the image given a fixed width across the screen based on the aspect ratio. All the articles I read says to make the cell calculation based on cellforRowAt, but my actual image is within the TableViewCell. Can someone please help?
Tableview controller:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "FeedTableViewCell", for: indexPath) as! FeedTableViewCell
cell.configureCell(post: postArray[indexPath.row])
return cell
}
TableViewCell:
func configureCell(post: Post){
self.postImage.sd_setImage(with: URL(string: post.postImageURL),
placeholderImage: UIImage(named: "default"))
}
you have cell.setNeedsLayout() inside the completion handler of setting image method, like this:
cell. postImage.kf.setImage(with: URL) { _, _, _, _ in
cell.layoutIfNeeded()
}
First of all, you need to use Autolayout to calculate the proper cell height by creating a proper set of constraints that would determine the cell height based on content. I am going to assume you did that.
Then you have to tell the tableView you want it to use Autolayout to calculate height:
// my best estimation of the height
tableView.estimatedRowHeight = 144
// but the real height is calculated by autolayout
tableView.rowHeight = UITableViewAutomaticDimension
Now this would work if the autolayout could calculate the height correctly in cellForRowAt. But since the image is downloaded asynchronously, the image is set later, when the cell may be already presented. This requires you to provide a way in which a cell can tell the tableView that it has downloaded its content and its layout needs to be recalculated. To do so, use this method in the viewController with the tableView:
func recalculateTableViewLayout() {
self.tableView.beginUpdates()
self.tableView.setNeedsLayout()
self.tableView.endUpdates()
}
You will need to pass the reference to the viewController with the tableView to each cell (I recommend to use delegate pattern for that, here for brevity I will simply sketch it using it directly):
class FeedTableViewCell: UITableViewCell {
weak var feedViewController: FeedViewController?
// etc.
And in the cellForRowAt:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "FeedTableViewCell", for: indexPath) as! FeedTableViewCell
cell.feedViewController = self
cell.configureCell(post: postArray[indexPath.row])
return cell
}
Then use completion handler of sd_setImage to tell the tableView to recalculate its layout when the image gets downloaded:
func configureCell(post: Post){
self.postImage.sd_setImage(with: URL(string: post.postImageURL), placeholderImage: UIImage(named: "default")) { (image, error, cache, url) in
self.feedViewController?.recalculateTableViewLayout()
}
}
Adding views programmatically into tableView cells making scroll jerky and slow. I am adding views programmatically into cell in the delegate function "CellForRowAt". I tried it through delegate function "WillDisplay" but the results are the same.
What is the best possible solution to achieve this?
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier:
"cell", for: indexPath) as! CustomCell
addViewsInCell(cell: cell, indexPath: indexPath)
return cell
}
func addViewsInCell(cell: CustomCell, indexPath: IndexPath) {
//here i am adding some views programmatically
for i in 0..<3 {
let customView: CustomView = Bundle.main.loadNibNamed("CustomView", owner: self, options: nil)![0] as! customView
cell.customViewPlacement.addSubview(customView)
}
}
Cell views are reused. Adding a subview every time in cellForRowAt indexPath: you end up with multiple copies of the same subview. Instead you should check whether that subview is already added. You could mark your subview with a tag and then use the viewWithTag method to test its presence.
Don't add any subviews/custom views inside tableView: cellForRowAt indexPath:. This will cause those subviews to be added repeatedly whenever that cell loaded by the table view. Instead create a subclass of UITableViewCell and create your subviews inside that subclass if you are working programmatically. Or else if you are working with storyboards, you can create a dynamic prototype cell.
I'm having a lot of issues getting my custom cells to use the dynamic row height.
Here is the xib of my custom cell.
In viewDidLoad for my table view, I set these values:
self.tableView.estimatedRowHeight = 80.0
self.tableView.rowHeight = UITableViewAutomaticDimension
but it doesn't seem to use the dynamic size when it loads the table.
Below is my cellForRowAtIndexPath function.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// Configure the cell...
let cell = Bundle.main.loadNibNamed("RedditCell", owner: self, options: nil)?.first as? RedditPostCellTableViewCell
let post = self.model?.getPostAt(index: indexPath.row)
cell?.title.text = post?.title
cell?.author.text = post?.author
cell?.upvotes.text = "\(post?.upvotes ?? -1)"
return cell!
}
I can't figure out why this isn't working. Any help would be appreciated!
Please try to set the height in the heightForRowAt
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
self.tableView.estimatedRowHeight = 80
return UITableViewAutomaticDimension
}
You don't need to pre-calculate the height. The problem is with your constraints in your custom UITableViewCell. Your constraints should be set up the way to force UITableViewCell to expand to show the whole label or any other content. Just setup constraints similar to my short example project: https://www.transfernow.net/216sw6l1bler?lng=en, and cell height will be automatically set, as you expected.
Screenshot:
In addition to setting the constraints so that the height of all of the elements in the cell + padding can be used to calculated the overall cell height, you must set the number of lines of your labels to zeros and set them to word wrap if these must grow based on content as well.
I custom my table view cell in storyboard to make a label center in cell.
but it seems having no affection.
my storyboard is like this:
actually it like this:
I only set label's text in code like this:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Movie", for: indexPath) as! ArchiveTableViewCell
cell.showChineseTitle.text = chineseTitleArray[indexPath.row]
return cell
}
why?
Thanks in advance!!!
remove leading and top constraint and set the width and height constraint to center the label in the cell. Set textAlignment property of label to center.
Try to add:
cell.showChineseTitle.textAlignment = .center
Becouse you do not set text alignment properly for the UILable. But only set position of it in cell.
How can I achieve this screen with UITableViewCell and UITableViewController. With table section and header. Some ideas to achieve this?? Thanks!
What have you tried so far?
Your question seems a little broad.
You will need a set of custom UITableViewCell Subclasses, which you design in nibs.
To make the cells seem apart from each other, resize the content size of the Cells, and make the cell background another color.
Create a Segmented Control and add it to the Tableviews HeaderView.
For the FooterView it seems like this is some kind of subclassed Tabbar.
Easiest way to customise it in such a way, would be to create a View, and add buttons to it. Add this View as Subview to your TableViewController.
Have 2 UITableViewCell's one for each type i.e. 1 for showing the image and text and another for showing just the text.
Then in the cellForRowAt delegate method determine which to type to use based off the object you are data binding it to.
Example:
public final func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let customObject = customObjects[indexPath.section]
switch customObject.type {
case .imageAndText:
if let cell = tableView.dequeueReusableCell(withIdentifier: ImageAndTextCell.identifier, for: indexPath) as? ImageAndTextCell {
cell.customObject = customObject
return cell
}
case .text:
if let cell = tableView.dequeueReusableCell(withIdentifier: TextCell.identifier, for: indexPath) as? TextCell {
cell.customObject = customObject
return cell
}
}
return UITableViewCell()
}