I'm trying to build a custom UITableView that acts in a similar way to the reminders app.
Instead of the top-most visible cell scrolling off the display, I want it to be covered by the next cell so the cells appear to stack on top of one another as you scroll.
Currently I am using:
override func scrollViewDidScroll(scrollView: UIScrollView) {
let topIndexPath: NSIndexPath = tableView.indexPathsForVisibleRows()?.first as! NSIndexPath
let topCell = tableView.cellForRowAtIndexPath(topIndexPath)
let frame = topCell!.frame
topCell!.frame = CGRectMake(frame.origin.x, scrollView.contentOffset.y, frame.size.width, frame.size.height)
}
But the top cell is always above the second cell - causing the second cell to scroll under it.
Also if I scroll quickly this seems to misplace all of my cells.
EDIT: Have fixed this. Answer posted below for future reference.
For anybody searching this in the future.
Simply loop through all the visible cells and set their z position to their row number (so each cell stacks above the previous one).
The if statement tells the top cell to remain at the contentOffset of the scrollview and for all other cells to assume their expected position. This stops the other cells being offset if you scroll too quickly.
override func scrollViewDidScroll(scrollView: UIScrollView) {
// Grab visible index paths
let indexPaths: Array = tableView.indexPathsForVisibleRows()!
var i = 0
for path in indexPaths {
let cell = tableView.cellForRowAtIndexPath(path as! NSIndexPath)
// set zPosition to row value (for stacking)
cell?.layer.zPosition = CGFloat(path.row)
// Check if top cell (first in indexPaths)
if (i == 0) {
let frame = cell!.frame
// keep top cell at the contentOffset of the scrollview (top of screen)
cell!.frame = CGRectMake(frame.origin.x,
scrollView.contentOffset.y,
frame.size.width,
frame.size.height)
} else {
// set cell's frame to expected value
cell!.frame = tableView.rectForRowAtIndexPath(path as! NSIndexPath)
}
i++
}
}
Related
I'm pretty new so apologies if my title doesn't phrase things correctly. I've been hacking away and haven't been able to find an answer to this problem.
I have a horizontally scrolling collection. I'm trying to visually show poll results programatically adding CGRect to the relevant item in the collection based on voting data held in a Firestore array.
This is working, but the problem is when you scroll away (so the item in the collection is off screen) and then back, the code to draw the CGRects gets triggered again and more graphics get added to the view. Is there a way to delete these CGRects when the user scrolls an item collection off screen so when the user scrolls the item back into view, code is triggered again it doesn't create duplicates?
Here are a couple of screenshots showing first and second load
Here is my code (cell b is where the CGrect gets triggered)
//COLLECTION VIEW CODE
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if collectionView == self.sentCollectionView {
let cellA = collectionView.dequeueReusableCell(withReuseIdentifier: "sCell", for: indexPath) as! SentCollectionViewCell
cellA.sentQuestionLabel.text = sentMessages[indexPath.row].shoutText
// Set up cell
return cellA
}
else {
let cellB = receivedCollectionView.dequeueReusableCell(withReuseIdentifier: "pCell", for: indexPath) as! ReceivedCollectionViewCell
receivedMessages[indexPath.row].pollTotal = receivedMessages[indexPath.row].pollResults.reduce(0, +)
print("Sum of Array is : ", receivedMessages[indexPath.row].pollTotal!)
cellB.receivedShoutLabel.text = receivedMessages[indexPath.row].shoutText
print(receivedMessages[indexPath.row].pollResults.count)
if receivedMessages[indexPath.row].pollResults != [] {
for i in 0...receivedMessages[indexPath.row].pollResults.count - 1 {
cellB.resultsView.addSubview(sq(pollSum: receivedMessages[indexPath.row].pollTotal!, pollResult: receivedMessages[indexPath.row].pollResults[i]))
}
}
return cellB
}
}
//THIS DRAWS THE CGRECT
func sq(pollSum: Int, pollResult: Int) -> UIView {
// divide the width by total responses
let screenDivisions = Int(view.frame.size.width) / pollSum
// the rectangle top left point x axis position.
let xPos = 0
// the rectangle width.
let rectWidth = pollResult * screenDivisions
// the rectangle height.
let rectHeight = 10
// Create a CGRect object which is used to render a rectangle.
let rectFrame: CGRect = CGRect(x:CGFloat(xPos), y:CGFloat(yPos), width:CGFloat(rectWidth), height:CGFloat(rectHeight))
// Create a UIView object which use above CGRect object.
let greenView = UIView(frame: rectFrame)
// Set UIView background color.
greenView.backgroundColor = UIColor.green
//increment y position
yPos = yPos + 25
return greenView
}
Cells of collection are dequeued dequeueReusableCell , you need to override prepareForReuse
Or set a tag
greenView.tag = 333
And inside cellForItemAt do this
cellB.resultsView.subviews.forEach {
if $0.tag == 333 {
$0.removeFromSuperview()
}
}
if receivedMessages[indexPath.row].pollResults != [] {
for i in 0...receivedMessages[indexPath.row].pollResults.count - 1 {
cellB.resultsView.addSubview(sq(pollSum: receivedMessages[indexPath.row].pollTotal!, pollResult: receivedMessages[indexPath.row].pollResults[i]))
}
}
In a section of my UITableView, there are 5 cells, three of which have been configured to expand/collapse to provide a more detailed view when selected. One of these cells shows a diagram of a number of small squares, which displays perfectly, until another cell is expanded, like this:
When the cell is collapsed, however, the subviews in the cell display in different cells, in different sections, like this:
and this:
To create the subviews in the cell, this is my code in the cellForRow method, which just uses an array of UIViews:
for vote in vote_array {
cell.contentView.addSubview(vote as? UIView ?? UIView.init(frame: CGRect.init(x: 0, y: 0, width: 0, height: 0)))
}
I tried removing all the subviews before I added them by doing this, but it doesn't change anything:
for subview in cell.contentView.subviews {
subview.removeFromSuperview()
}
Edit: This is inside a switch statement, but here is the relevant cell/case cellForRow:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.contentView.clipsToBounds = true
cell.clipsToBounds = true
let vote_array = getVoteArray()
for subview in cell.contentView.subviews {
subview.removeFromSuperview()
}
for case let vote as UIView in vote_array {
cell.contentView.addSubview(vote)
}
Edit:
The core of getVoteArray:
func getVoteArray() -> NSMutableArray {
var i = 0
var x = 20
var y = 4
let blockViews : NSMutableArray = []
for color in blocks {
let block = UIView.init(frame: CGRect.init(x: x, y: y, width: 20, height: 20))
block.backgroundColor = color as? UIColor
blockViews.add(block)
x = x + 24
i = i + 1
if i == num_blocks_per_row { i = 0; y = y + 24; x = 20 }
}
diagramHeight = y + 24
return blockViews
}
I can't seem to figure out why the subviews are generating randomly all over the tableView.
Ended up adding
for case let cell as UITableViewCell in tableView.subviews {
for subview in cell.contentView.subviews {
if subview.tag == 115 {
subview.removeFromSuperview()
}
}
}
to my didSelectRowAt method, after adding the tag when each view is created. I'm still not sure why the views were being added to different cells, but this got rid of them at least.
Try to implement unique ReuseIdentifiers for collapsed and expanded states.
If the cell is collapsed then don't load all those views in it by dequeuing a collapsedCell where the height of all those UIViews is either 0 or they are not added to subview.
If the cell is expanded than deque a expandedCell where the views are layed out as in the first screenshot.
After expanding and or collapsing call tableview.reloadData()
It used to be a long long time ago that UIViews clipped their children, but that hasn't been true for a very long time. If you want clipping on you need to either change UIView.clipsToBounds to true or use the underlying CALayer property maskToBounds.
cell.contentView.clipsToBounds = true
Or you can check the box in the storyboard/nib.
Is there a practice to scroll a collection view with cells, and, depending on its content offset, scroll the other collection view?
I have a main collection view that has two cells and scrolls horizontally. Then I have a second collection view with cells that scrolls vertically. What happens is when I scroll up, then scroll horizontally to the second vertical cv, it's not synced with relation to the first.
I overrode the scrollViewDidScroll inside the vertically scrolling collection view (not the main one, because it scrolls horizontally), to no avail (** means the parts that don't work to achieve my effect).
var didScrollPastProfileView: Bool = false
func scrollViewDidScroll(scrollView: UIScrollView) {
let collectionViewDictionary = ["scrollView": self.collectionView]
NSNotificationCenter.defaultCenter().postNotificationName("cvDidScroll", object: nil, userInfo: collectionViewDictionary)
if scrollView.contentOffset.y > 250 {
**self.didScrollPastProfileView = true
if self.didScrollPastProfileView {
let previousContentOffset = scrollView.contentOffset.y
scrollView.contentOffset.y = previousContentOffset
}**
} else if scrollView.contentOffset.y < 250 {
**let previousContentOffset = scrollView.contentOffset.y
scrollView.contentOffset.y = previousContentOffset
self.didScrollPastProfileView = false**
}
}
Here's a visual:
Notice how there's space above when I scroll to the second cell? I want that vertical scroll view to follow the first. Any suggestions?
EDIT: I tried to access the second cell of the horizontal collection view while I was scrolling in the first cell, and I tried to change contentOffSet.y when I scrolled down in the first one, but I got an EXC_BAD_ACCESS error.
if scrollView.contentOffset.y <= 250.0 {
let groupsPosts = childViewControllerForPosts.collectionView(childViewControllerForPosts.collectionView!, cellForItemAtIndexPath: NSIndexPath(forItem: 1, inSection: 0)) as! FeedCell
groupsPosts.collectionView.contentOffset.y = -scrollView.contentOffset.y
self.topVerticalConstraint?.constant = -scrollView.contentOffset.y
You can do something like this when scrolled to the collectionViewB with animated to false so it look like it is synchronised.
let indexPath = collectionViewA.indexPathsForVisibleItems().first
self.collectionViewB.scrollToItemAtIndexPath(indexPath, atScrollPosition: UICollectionViewScrollPosition.Top, animated: false)
Not exactly sure how you set up this two collection. If you do not have access to collectionViewA then you might have to save the current indexPath to a variable and pass it over.
I'm building an iOS app in swift with Xcode 6.
I'm trying to embed a view controller with a table view in a scrollview. When the user drags in the table view, it is suppose to move the table, not the the scrollview that it is embedded in.
I've made this illustration, to clearify my view and view controller hierachy:
The red area is the content size area of the scrollview.
The green and blue areas are different view controllers, embedded in the scrollview.
The yellow area is a Text field in the blue view controller.
The orange area is a table view in the blue view controller.
I have enabled paging in the scrollview, so that it snaps to either the green or blue view controller. How can I pop the Table view to the top of the view hierachy, so that the only way to scroll the scrollview, will be to drag in the text field.
import UIKit
class RootViewController: UIViewController, UIScrollViewDelegate {
var scrollView: UIScrollView!
var greenViewController: GreenViewController!
var blueViewController: BlueViewController!
override func viewDidLoad() {
super.viewDidLoad()
scrollView = UIScrollView(frame: CGRectMake(0, 0, self.view.frame.width, self.view.frame.height))
scrollView.delegate = self
scrollView.pagingEnabled = true
self.greenViewController = self.storyboard?.instantiateViewControllerWithIdentifier("Green View Controller") as! GreenViewController
self.blueViewController = self.storyboard?.instantiateViewControllerWithIdentifier("Blue View Controller") as! BlueViewController
greenViewController.view.frame = CGRectMake(0, 0, view.bounds.width, view.bounds.height)
blueViewController = CGRectMake(0, view.bounds.height, view.bounds.width, view.bounds.height)
scrollView.addSubview(greenViewController.view)
scrollView.addSubview(blueViewController.view)
scrollView.contentSize = CGSizeMake(view.bounds.width, view.bounds.height*2)
self.view.addSubview(scrollView)
}
I hope that I have expressed myself clearly.
EDIT:
I've tried changing the size of the scrollview, when it scrolls. The idea was to change the height of the frame so it matches the height of the textfield when it is scrolled all the way down. But it seems that it also changes the visible part of whats embedded in the scrollview:
func scrollViewDidScroll(scrollView: UIScrollView) {
if self.scrollView.contentOffset.y > textField.View.bounds.height {
self.scrollView.frame.size.height = view.bounds.height - scrollView.contentOffset.y - textField.View.bounds.height
println(self.scrollView.frame)
}
}
Ok it might be bit late now but still i m posting this as a tutorial !
This is a less prefered way to achieve this. Better way would be,
Using table view controller as parent view and then using prototype cells as static cell(In 'n' numbers as per your requirement) as a card view or for any other use
The every different cell used would be considered as a section and no of prototype cells will be equal to no of sections in code as in snippet below
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 3
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if section == 2 {
return list.count
}
return 1
}
number of rows in case of section 0 and 1 would be 1 as static part
Whereas No of rows in case of section 2 i.e dynamic part would be equal to count of list.
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell : CustomTableViewCell.swift = CustomTableViewCell.swift()
switch indexPath.section {
case 0:
cell = tableView.dequeueReusableCellWithIdentifier("staticCell1", forIndexPath: indexPath) as! CustomTableViewCell
break
case 1:
cell = tableView.dequeueReusableCellWithIdentifier("staticCell2", forIndexPath: indexPath) as! CustomTableViewCell
break
case 2:
cell = tableView.dequeueReusableCellWithIdentifier("dynamicCell", forIndexPath: indexPath) as! CustomTableViewCell
break
default:
break
}
return cell;
}
and thats it! Work is done! Party!
I got reference from here
Mixing static and dynamic sections in a grouped table view?
I mocked this up. My View hierarchy looks like this
ViewController's UIView
...UIView (to act as a container view for all the scrollable content)
.......UIView (for the top content) - green
.......UIView (for the bottom content) - blue
............UILabel
............UITableView (with scrollable content - more rows than visible)
I wired #IBOutlets to the UIScrollView (scrollView) and UIView (containerView) for the scrollable area.
in viewDidLoad I added:
scrollView.contentSize = containerView.frame.size
If I click anywhere outside the tableView (top area, text area, etc...) I scrolls the scrollView. If I try to scroll in the table view, the tableView scrolls (the scrollView does not).
Is that what you were trying to achieve?
I haven't been able to find any examples of this online. How can I achieve the following effect? Instead of the standard slide-to-left effect when tapping a table row, I'd like the view controller transition animation to look like the following:
User taps a cell in the table
The cell starts growing to fill the screen, pushing other rows above and below it "offscreen".
As the cell grows, cells elements (text, images, etc.) cross-fade into the new view's contents until the new view completely fills the screen.
I'd like to also be able to interactively transition back into the table view by dragging up from the bottom edge, such that the reverse of the above is achieved. i.e. view starts shrinking back into a normal table view cell as the "offscreen" cells animate back into position.
I've thought about taking a snapshot of the table and splitting it up at the points above and below the cell, and animating these snapshots offscreen as part of a custom view controller transition. Is there a better way? Ideally I'd like to not take snapshots, as I may want to have animations, etc., still happening in the table view rows as they fade offscreen.
First thing first, i have seen your post today and his is written in swift programming language.
the follwing code is to expand the selected cell to the full screen, where the subviews will fade out and background image will expands.
First complete cellForRowAtIndexPath, then in didSelectRowAtIndexPath,
func tableView(tableView: UITableView!, didSelectRowAtIndexPath indexPath: NSIndexPath!) {
isSelected = true
selectedCellIndex = indexPath.row
tableView.beginUpdates()
var cellSelected: UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
cellSelected.frame = tableCities.rectForRowAtIndexPath(indexPath)
println("cell frame: \(cellSelected) and center: \(cellSelected.center)")
let newCell = cellSelected.frame.origin.y - tableOffset
println("new cell origin: \(newCell)")
var tempFrame: CGRect = cellSelected.frame
variableHeight = cellSelected.frame.origin.y - tableOffset
tempFrame.size.height = self.view.frame.height
println("contentoffset: \(tableView.contentOffset)")
let offset = tableView.contentOffset.y
println("cell tag: \(cellSelected.contentView.tag)")
let viewCell: UIView? = cellSelected.contentView.viewWithTag(cellSelected.contentView.tag)
println("label: \(viewCell)")
viewCell!.alpha = 1
UIView.animateWithDuration(5.0, delay: 0.1, options: UIViewAnimationOptions.BeginFromCurrentState, animations: {
tableView.setContentOffset(CGPointMake(0, offset + self.variableHeight), animated: false)
tableView.contentInset = UIEdgeInsetsMake(0, 0, self.variableHeight, 0)
tableView.endUpdates()
cellSelected.frame = tempFrame
viewCell!.alpha = 0
println("contentoffset: \(tableView.contentOffset)")
}, completion: nil)
}
then update your heightForRowAtIndexPath, as
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
if isSelected && (selectedCellIndex == indexPath.row) {
return self.view.frame.height
}else {
return 100
}
}
Ignore this if already solved. and this might be helpful to others.