I have the strangest glitch after I select a UITableView cell and scroll away(You can see it here):
When I select a cell, it's programmed to change its text and change the font color from brown to red. However, when I scroll, other cells that I have not selected change their font color to red. And when I scroll back to the selected cell it reverts to its original text and sometimes, its font color too (from red to brown).
I've used this post in attempt to fix it. But still the glitch remains.
I am completely baffled as to why this is happening and would love love love if anyone could tell me why.
In my code I made my ViewController CategoryViewController the UITableView's Datasource & Delegate instead of a UITableViewController b/c I have other views in my CategoryViewController, not just a UITableView
class CategoryViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
private let themeColors = ThemeColors()
private let expensesOrganizer = ExpensesOrganizer()
override func viewDidLoad() {
super.viewDidLoad()
//Set up subCategory table view
subCategoryTableView.dataSource = self
subCategoryTableView.delegate = self
}
// MARK: UITableViewDataSource
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return expensesOrganizer.getNumOfSubcategoriesFor(category!)
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let subcategoryCell = tableView.dequeueReusableCellWithIdentifier("subCategoryCell", forIndexPath: indexPath) as! SubcategoryTableViewCell
let subcategory = expensesOrganizer.getSubcategoryFor(category!, index: indexPath.row)
subcategoryCell.subCategoryLabel.text = "\(indexPath.row) \(expensesOrganizer.getText(subcategory.rawValue))"
subcategoryCell.selectedBackgroundView = UIView(frame: CGRect.zero)
subcategoryCell.selectedBackgroundView?.backgroundColor = themeColors.getColorOfCategory(category!)
return subcategoryCell
}
// MARK: UITableViewDelegate
var indexPathSelectedCell: NSIndexPath?
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let subcategoryCell = tableView.cellForRowAtIndexPath(indexPath) as! SubcategoryTableViewCell
subcategoryCell.subCategoryLabel.textColor = UIColor.redColor()
subcategoryCell.subCategoryLabel.text = "\(indexPath.row) didSELECTRowAtIndexPath called"
indexPathSelectedCell = indexPath
//What the post said to add:
let selectedRows = subCategoryTableView.indexPathsForSelectedRows
for i in selectedRows! {
if !i.isEqual(indexPath){
subCategoryTableView.deselectRowAtIndexPath(i, animated: false)
}
}
}
func tableView(tableView: UITableView, didDeselectRowAtIndexPath indexPath: NSIndexPath) {
let subcategoryCell = tableView.cellForRowAtIndexPath(indexPath) as! SubcategoryTableViewCell
subcategoryCell.subCategoryLabel.textColor = themeColors.getFontColor(Shade.Light)
subcategoryCell.subCategoryLabel.text = "\(indexPath.row) didDESELECTRowAtIndexPath called"
}
The approach that you take is incorrect, because you are not setting the color when you reuse a cell. Your cellForRowAtIndexPath needs to set color back to brown if the cell is not selected. It should be set to red if the cell is selected:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let subcategoryCell = tableView.dequeueReusableCellWithIdentifier("subCategoryCell", forIndexPath: indexPath) as! SubcategoryTableViewCell
let subcategory = expensesOrganizer.getSubcategoryFor(category!, index: indexPath.row)
subcategoryCell.subCategoryLabel.text = "\(indexPath.row) \(expensesOrganizer.getText(subcategory.rawValue))"
subcategoryCell.selectedBackgroundView = UIView(frame: CGRect.zero)
subcategoryCell.selectedBackgroundView?.backgroundColor = themeColors.getColorOfCategory(category!)
if let selected = tableView.indexPathsForSelectedRows() as? [NSIndexPath] && selected! == indexPath {
subcategoryCell.subCategoryLabel.textColor = UIColor.brownColor()
} else {
subcategoryCell.subCategoryLabel.textColor = UIColor.redColor()
}
return subcategoryCell
}
This has to do with cell reuse.
When you change the color of the label in didSelectRowAtIndexPath, then scroll that cell off-screen, it gets reused for a different cell that will appear on-screen.
However, since you don't prepare the cell for reuse, it is still using the selected font color for your label.
Assigning the label's default text color in prepareForReuse or cellForRowAtIndexPath will fix this issue.
Related
I'm trying to display on screen some logs through UiTableView and I want to set a red text color to those hasPrefix "root" as following :
var logList: [String] = []
...
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.logList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableview.dequeueReusableCell(withIdentifier: "cellId", for: indexPath) as! ItemLogCell
cell.itemLogLabel.text = self.logList[indexPath.row]
print(indexPath.row)
print(self.logList[indexPath.row].hasPrefix("root"))
if (self.logList[indexPath.row].hasPrefix("root")) {
cell.itemLogLabel.textColor = UIColor.red
}
return cell
}
The problem is even when the prefix condition is false, text color become red and only for some row.
The more I scroll the more there are random red logs. How can I fix this ?
You can do something like this to reset the color of the other lines :
if (self.logList[indexPath.row].hasPrefix("root")) {
cell.itemLogLabel.textColor = UIColor.red
}
else {
cell.itemLogLabel.textColor = UIColor.white
}
Use instead different UITableViewDelegate callback for that
func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
guard let cell = cell as? ItemLogCell else { return }
print(indexPath.row)
print(self.logList[indexPath.row].hasPrefix("root"))
if (self.logList[indexPath.row].hasPrefix("root")) {
cell.itemLogLabel.textColor = UIColor.red
}
}
Because UITableViewCell is basically reusable. Imagine that you are seeing there are 6 cells in the screen, index 0 to 5. When you scroll to cell with index 6, the cell with index 0 will be hidden. TableView will not create a new UITableViewCell for the cell 6, it will waste the device's memory. Instead, tableview will dequeue the cell 0 and reuse it. So, cell 6 will has the default value of cell 0. To fix this issue, you will need to set the color again, of the cell that does not has prefix "root"
if (self.logList[indexPath.row].hasPrefix("root")) {
cell.itemLogLabel.textColor = UIColor.red
} else {
cell.itemLogLabel.textColor = UIColor.black
}
As pham hai explain cells are reusable so You should consider else case as well. Shorty
let cellColor = cell.itemLogLabel.textColor
self.logList[indexPath.row].hasPrefix("root") ? cellColor = .red : cellColor = .black
So I'm setting a UITableViewCell's layout programmatically when it is selected:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
self.selectedCellIndexPath = indexPath
var selectedCell = tableView.cellForRowAtIndexPath(indexPath)!
tableView.beginUpdates()
tableView.endUpdates()
var cell:SelectedPatientCell = tableView.dequeueReusableCellWithIdentifier("patient selected", forIndexPath: indexPath) as! SelectedPatientCell
cell.patientName.text = patients[indexPath.row].fullName
cell.dob.text = patients[indexPath.row].dob
...
selectedCell = cell
}
And when I scroll the tableView, the layout of the cell resets to its original layout set in cellForRowAtIndexPath. However, the height stays as it should when I set it in the function above. Does anyone know how to fix this?
Here is an album of what's happening:
http://imgur.com/a/OUIMJ
Image 1:original state
Image 2: selected state (how it should stay on scrolling)
Image 3: what actually happens
you should hold this state in
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
if indexPath == self.selectedCellIndexPath {
var cell:SelectedPatientCell = tableView.dequeueReusableCellWithIdentifier("patient selected", forIndexPath: indexPath) as! SelectedPatientCell
cell.patientName.text = patients[indexPath.row].fullName
cell.dob.text = patients[indexPath.row].dob
return cell
}
let cell = tableView.dequeueReusableCellWithIdentifier("patient selected") as! OriCell
...
return cell
}
in this way if you scroll tableView,it won't resume to original Cell.
Hopefully it is clear.
So I found my own solution:
Instead of doing
tableView.beginUpdates()
tableView.endUpdates()
I needed to do this at the end of the function:
tableView.reloadData()
and that solves the issue
I have a UITableViewController. It has one prototype cell, and spawns anywhere from 0 to 100 cells based on a user query. Once they load, I want an IBAction to trigger if a user taps anywhere within the cell EXCEPT for a specific button. I have multiple labels, and I still want the IBAction to be triggered if user taps on them. How do I accomplish this?
Here's my code for loading the tables:
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cellIdentifier = "Cell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! TypeOfActivityTableViewCell
cell.activityLabel?.text = activityNames[indexPath.row]
cell.bgImage?.image = UIImage(named: activityPic[indexPath.row])
cell.sloganLabel?.text = slogan[indexPath.row]
return cell
}
I do not want to code all this within tableView for MVC principles.
For tapping anywhere in the cell you need not configure an IBAction. Just use the default UITableViewDelegate i.e:
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath){
let geoSearchWord = "geoSearchWord" + searchQuery[indexPath.row]
let geoSearchLat = "&geoSearchWordLat=" + (lat == "" ? "33.9700" : lat)
let geoSearchLon = "&geoSearchWordLon=" + (lat == "" ? "-118.4180" : lon)
let geoSearchRadius = "&geoSearchWordRad=5mi"
let twitterURLRequest: String = "https://quiet-cove-5048.herokuapp.com/tw?\(geoSearchWord)\(geoSearchLat)\ (geoSearchLon)\(geoSearchRadius)"
alamoRequest(twitterURLRequest)
}
Else if you have Buttons inside your cell for specific actions. You will have to add action to that button and assign a tag for identification(which button is tapped).
You can add action in cellForRowAtIndexPath
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cellIdentifier = "Cell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! TypeOfActivityTableViewCell
cell.activityLabel?.text = activityNames[indexPath.row]
cell.bgImage?.image = UIImage(named: activityPic[indexPath.row])
cell.sloganLabel?.text = slogan[indexPath.row]
cell.myButton.addTarget(self, action: "myAction:", forControlEvents: .TouchUpInside)
cell.myButton.tag = indexPath.row
return cell
}
Tapping on a button inside the cell will execute the below function:
func myAction(sender:UIButton){
let selectedActivityName = activityNames[sender.tag]
}
Here is one crafty solution.You can add an UIControl(e.g. UIButton) to receive touch in that special area.And then receive events in UITableViewDelegate: tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
If you want click any where in cell then you can use its delegate methods
i.e
tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
And if you want to add UIControl and on touch event of that control you need to do as follows:
First You need to add target for your control in your cellForRowAtIndexPath as below.
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cellIdentifier = "Cell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! TypeOfActivityTableViewCell
cell.activityLabel?.text = activityNames[indexPath.row]
cell.bgImage?.image = UIImage(named: activityPic[indexPath.row])
cell.sloganLabel?.text = slogan[indexPath.row]
cell.btn.addTarget(self, action: "btnClickAction", forControlEvents: UIControlEvents.TouchDragInside)
return cell
}
Button Click fucntion:
func btnClickAction(sender: UIButton)
{
var superView = sender.superview
while superView?.isKindOfClass(UITableViewCell) == false
{
superView = superView?.superview
}
var cell = superView as! UITableViewCell
var indexPath = self.tableView.indexPathForCell(cell)! as NSIndexPath
}
In above code you will find indexPath.
My table view has some elements sorted by some types: TypeA, TypeB and TypeC.
I want that when I click on a cell with TypeA to change the selection color to Red, when I type on TypeB to change color to Blue and when pressing on TypeC to change color to Yellow.
Right now I came up with this code:
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
tableView.deselectRowAtIndexPath(indexPath, animated: true)
}
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
guard let mode = dataSource.selectedObject else {
fatalError("willDisplayCell, but no selected row?")
}
let type = ModeType(rawValue: mode.type)!
let selectionColor = UIView() as UIView
selectionColor.backgroundColor = type.color()
cell.selectedBackgroundView = selectionColor
}
My issue with this is that willDisplayCell is called when I start my app and my data source is empty so I get a fatal error.
How can I overcome this ? Maybe using a flag to do this only when didSelectRowAtIndexPath was called.
Or is there another way to achieve what I am after ?
I assume you have created custom UITableviewCell. Create a cell type enum.
enum CellType {
case RedCell
case Yellowcell
case OrangeCell
}
//Create enum property
class CustomCell : UITableViewCell {
var cellType:CellType = CellType.RedCell //Default is RedCell
}
Now you have to assign the cell type in your ViewController tableview datasource.
override func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell") as! CustomCell
cell.cellType = .RedCell //your choice
return cell
}
override func tableView(tableView: UITableView, shouldHighlightRowAtIndexPath indexPath: NSIndexPath) -> Bool {
return true
}
override func tableView(tableView: UITableView, didHighlightRowAtIndexPath indexPath: NSIndexPath) {
var cell = tableView.cellForRowAtIndexPath(indexPath)
switch(cell.cellType) {
//Handle Switch case
case .RedCell:
cell?.contentView.backgroundColor = UIColor.redColor()
cell?.backgroundColor = UIColor.redColor()
}
}
override func tableView(tableView: UITableView, didUnhighlightRowAtIndexPath indexPath: NSIndexPath) {
var cell = tableView.cellForRowAtIndexPath(indexPath)
// Set unhighlighted color
cell?.contentView.backgroundColor = UIColor.blackColor()
cell?.backgroundColor = UIColor.blackColor()
}
EDIT:
If you have created 3 different types of cell class check tableview cell class type and change the color in didHighlightRowAtIndexPath method.
My issue with this is that willDisplayCell is called when I start my
app and my data source is empty so I get a fatal error.
tableView(_:willDisplayCell:forRowAtIndexPath:) will only be called if your data source tells the table view that there are rows to display. So the problem more likely is that your tableView(_:numberOfRowsInSection:) method is returning a number larger than zero when your data source is empty.
Also, your code looks like it expects tableView(_:willDisplayCell:forRowAtIndexPath:) to get called only for selected rows. It gets called for all displayed rows. But this method isn't necessary to affect the background color. In fact, it's rarely used in most apps. There are only a few edge cases where you need to mess with the cell just before it's displayed.
The proper way to set the selection background color is to create and assign a UIView to the cell's selectedBackgroundView property. You can do that either from the cell's subclass (preferred for complex cells) or from the tableView:cellForRowAtIndexPath: data source method:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("MyCell")
cell!.textLabel?.text = "Kilroy was here."
cell!.selectedBackgroundView = UIView(frame: cell!.bounds)
cell!.selectedBackgroundView!.backgroundColor = .greenColor()
return cell!
}
I have a regular UITableView with single selection enabled. My problem is that if the user selects multiple rows then the original rows remain selected. I also have a problem where the highlight remains gray no matter if I set the cell.selectionStyle = UITableViewCellSelectionStyle.Blue
My view controller is defined in the Storyboard.
Table View
Content: Dynamic Prototypes
Selection: Single Selection
Show Selection on Touch [X]
Background: Black Color
Index Row Limit: 0
Table Cell View
Style: Custom
Selection: Blue
Background: Black Color
Here are some screenshots:
Here is my code:
class AreaViewController: UITableViewController
{
override func viewDidLoad()
{
super.viewDidLoad()
self.tableView.backgroundColor = backgroundColour
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCellWithIdentifier("areacell", forIndexPath: indexPath) as! UITableViewCell
cell.selectionStyle = UITableViewCellSelectionStyle.Blue
cell.textLabel?.text = "Cell Contents"
cell.textLabel?.textColor = UIColor.whiteColor()
return cell
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
{
let cell = tableView.dequeueReusableCellWithIdentifier("areacell", forIndexPath: indexPath) as! UITableViewCell
}
}
I must be missing something obvious but I've not been able to see anything non standard.
From the UITableViewCell Class Reference
UITableViewCellSelectionStyleBlue The cell has a default background
color when selected.
In iOS 7, the selection color is no longer blue. Use
UITableViewCellSelectionStyleDefault instead.
If you want a special background color for selected cells you have to set the cells' backgroundView:
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("myCell", forIndexPath: indexPath) as! UITableViewCell
// Configure the cell...
let backgroundView = UIView()
backgroundView.backgroundColor = UIColor.redColor()
cell.selectedBackgroundView = backgroundView
return cell
}
Looks like this:
Argh! I found it at last. Seems like I was calling let cell = tableView.dequeueReusableCellWithIdentifier("areacell", forIndexPath: indexPath) as! UITableViewCell in the didSelectRowAtIndexPath method. Removing it caused everything to start working again. Obvious really. Thanks for your help zisoft in putting me on the right road.