The code I used to create a rectangle (at least until iOS7) was
CGRect rect = [cTableView frame];
rect.origin.y += [cTableView rowHeight];
searchOverlayView = [[BecomeFirstResponderControl alloc] initWithFrame:rect];
On iOS7, cTableView (an instance of a UITableView) returned 44. Testing in iOS8 with an iPhone 5s returns -1.
Why is this happening? What is the correct code that needs to be used in order for my app to be backwards compatible with iOS7?
Apple changed the default row height in iOS8 to UITableViewAutomaticDimension, which is declared as -1. This means that your table view is set up for automatic cell height calculation.
You will either need to implement autoLayout (recommended) or implement the new delegate method: heightForRowAtIndexPath. Here's a great question about auto layout: Using Auto Layout in UITableView for dynamic cell layouts & variable row heights
Seems like you were effectively hard coding 44 (the old default) anyway, though, so you could just do that (not recommended).
This made me struggle for hours. I ended up hard coding the value to 44:
self.tableView.rowHeight = 44;
There is a performance penalty for implementing heightForRowAtIndexPath that I prefer not to incur when all rows in a table are the same height and never change at runtime (it is called once for every row, each time the table is displayed).
In this situation, I continue to set "Row Height" in the XIB and use the following iOS 8 friendly code when I need rowHeight (it works on iOS 7 and below too).
NSInteger aRowHeight = self.tableView.rowHeight;
if (-1 == aRowHeight)
{
aRowHeight = 44;
}
This allows you to keep freely editing Row Height in the XIB and will work even if Apple fixes this bug/feature in the future and a XIB set Row Height = 44 stops coming back as -1.
If you accidentally change the row height in IB from 44 to something else (like 40), automatic cell size calculation fails. You owe me 3 hours, Apple.
My solution to this problem:
#interface MCDummyTableView () <UITableViewDataSource, UITableViewDelegate>
#end
#implementation MCDummyTableView
- (instancetype) initWithFrame:(CGRect)frame style:(UITableViewStyle)style {
frame = (CGRect){ 0, 0, 100, 100 };
self = [super initWithFrame:frame style:style];
if(!self) return self;
self.dataSource = self;
self.delegate = self;
[self registerClass:[UITableViewCell class] forCellReuseIdentifier:#"CELL"];
return self;
}
- (NSInteger) numberOfSections {
return 1;
}
- (NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 1;
}
- (UITableViewCell*) cellForRowAtIndexPath:(NSIndexPath*)indexPath {
/*
UITableView doesn't want to generate cells until it's in the view hiearchy, this fixes that.
However, if this breaks (or you don't like it) you can always add your UITableView to a UIWindow, then destroy it
(that is likely the safer solution).
*/
return [self.dataSource tableView:self cellForRowAtIndexPath:indexPath];
}
- (UITableViewCell*) tableView:(UITableView*)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath {
return [self dequeueReusableCellWithIdentifier:#"CELL"];
}
- (CGFloat) defaultRowHeight {
return [self cellForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]].frame.size.height;
}
#end
I really don't like hardcoding things. I use this class to cache the default cell height early on in the app.
One more consideration is that if you are calculating the height based on existing view dimensions, the heightForRowAtIndexPath method may be called before viewDidLayoutSubviews.
In this case, override viewDidLayoutSubviews, and recalculate the frame.size.height value for all the visible cells.
Related
I have an UITableViewController that contains a custom cell. Each cell was created using a nib and contains a single non-scrollable UITextView. I have added constraints inside each cell so that the cell adapts its height to the content of the UITextView. So initially my controller looks like this :
Now I want that when the user types something in a cell its content automatically adapts. This question has been asked many times, see in particular this or the second answer here. I have thus written the following delegate in my code :
- (BOOL) textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text {
[self.tableView beginUpdates];
[self.tableView endUpdates];
return YES;
}
However it leads to the following strange behavior : all constraints are ignored and all cells height collapse to the minimal value. See the picture below:
If I scroll down and up the tableView in order to force for a new call of cellForRowAtIndexPath, I recover the correct heights for the cells:
Note that I did not implement heightForRowAtIndexPath as I expect autoLayout to take care of this.
Could someone tell me what I did wrong or help me out here ? Thank you very much !
Here is a swift solution that is working fine for me. Provided you are using auto layout, you need assign a value to estimatedRowHeight and then return UITableViewAutomaticDimension for the row height. Finally do something similar to below in the text view delegate.
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.estimatedRowHeight = 44.0
}
override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
// MARK: UITextViewDelegate
func textViewDidChange(textView: UITextView) {
// Calculate if the text view will change height, then only force
// the table to update if it does. Also disable animations to
// prevent "jankiness".
let startHeight = textView.frame.size.height
let calcHeight = textView.sizeThatFits(textView.frame.size).height //iOS 8+ only
if startHeight != calcHeight {
UIView.setAnimationsEnabled(false) // Disable animations
self.tableView.beginUpdates()
self.tableView.endUpdates()
// Might need to insert additional stuff here if scrolls
// table in an unexpected way. This scrolls to the bottom
// of the table. (Though you might need something more
// complicated if editing in the middle.)
let scrollTo = self.tableView.contentSize.height - self.tableView.frame.size.height
self.tableView.setContentOffset(CGPoint(x: 0, y: scrollTo), animated: false)
UIView.setAnimationsEnabled(true) // Re-enable animations.
}
My solution is similar to #atlwx but a bit shorter. Tested with static table. UIView.setAnimationsEnabled(false) is needed to prevent cell's contents "jumping" while table updates that cell's height
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.estimatedRowHeight = 44.0
}
override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
func textViewDidChange(_ textView: UITextView) {
UIView.setAnimationsEnabled(false)
textView.sizeToFit()
self.tableView.beginUpdates()
self.tableView.endUpdates()
UIView.setAnimationsEnabled(true)
}
Tested on iOS 12
I really tried a lot of solutions and finally found a good one here
This works with animation and looks beautiful. The trick was the DispatchQueue.async block.
I also used TPKeyboardAvoidingTableView to make sure the keyboard doesn't overlap anything.
func textViewDidChange(_ textView: UITextView) {
// Animated height update
DispatchQueue.main.async {
self.tableView?.beginUpdates()
self.tableView?.endUpdates()
}
}
UPDATE
I got strange jumping issues because of TPKeyboardAvoidingTableView. Especially when I scrolled to the bottom and then a UITextView got active.
So I replaced TPKeyboardAvoidingTableView by native UITableView and handle the insets myself. The table view is does the scrolling natively.
The following example works for dynamic row height as the user types text into the cell. Even if you use auto layout you still have to implement the heightForRowAtIndexPath method. For this example to work constraints must be set to textView in such a way that if cell height increases textView will also grow in height. This can be achieved by adding a top constraint and bottom constraint from textView to cell content view. But do not set height constraint for textView itself. Also enable scrolling for the textView so that textView's content size will be updated as the user enters text. Then we use this content size to calculate the new row height. As long as the row height is long enough to vertically stretch the textView to equal to or greater than its content size the text view will not scroll even if scroll is enabled and that is what you need I believe.
In this example I have only a single row and I use only a single variable to keep track of the row height. But when we have multiple rows we need a variable for each row otherwise all the rows will have the same height. An array of rowHeight that corresponds to the tableView data source array may be used in that case.
#interface ViewController ()
#property (nonatomic, assign)CGFloat rowHeight;;
#property (weak, nonatomic) IBOutlet UITableView *tableView;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.rowHeight = 60;
}
#pragma mark - UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 1;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell1"];
return cell;
}
#pragma mark - UITableViewDelegate
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return self.rowHeight;
}
#pragma mark - UITextViewDelegate
- (void)textViewDidChange:(UITextView *)textView {
[self.tableView beginUpdates];
CGFloat paddingForTextView = 40; //Padding varies depending on your cell design
self.rowHeight = textView.contentSize.height + paddingForTextView;
[self.tableView endUpdates];
}
#end
Using Swift 2.2 (earlier versions would likely work too), if you set the TableView to use auto dimensions (assuming you're working in a subclassed UITableViewController, like so:
self.tableView.rowHeight = UITableViewAutomaticDimension
self.tableView.estimatedRowHeight = 50 // or something
You just need to implement the delegate in this file, UITextViewDelegate, and add the below function, and it should work. Just remember to set your textView's delegate to self (so, perhaps after you've dequeued the cell, cell.myTextView.delegate = self)
func textViewDidChange(textView: UITextView) {
self.tableView.beginUpdates()
textView.frame = CGRectMake(textView.frame.minX, textView.frame.minY, textView.frame.width, textView.contentSize.height + 40)
self.tableView.endUpdates()
}
Thanks to "Jose Tomy Joseph" for inspiring (enabling, really) this answer.
I've implemented a similar approach using a UITextView however to do so I had to implement heightForRowAtIndexPath
#pragma mark - SizingCell
- (USNTextViewTableViewCell *)sizingCell
{
if (!_sizingCell)
{
_sizingCell = [[USNTextViewTableViewCell alloc] initWithFrame:CGRectMake(0.0f,
0.0f,
self.tableView.frame.size.width,
0.0f)];
}
return _sizingCell;
}
#pragma mark - UITableViewDelegate
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
self.sizingCell.textView.text = self.profileUpdate.bio;
[self.sizingCell setNeedsUpdateConstraints];
[self.sizingCell updateConstraintsIfNeeded];
[self.sizingCell setNeedsLayout];
[self.sizingCell layoutIfNeeded];
CGSize cellSize = [self.sizingCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
return cellSize.height;
}
sizingCell is an instance of the cell that is only used for sizing calculations.
What's important to note is that you need to attach the UITextView's upper and lower edge to the UITableViewCells contentView's upper and lower edge so that as the UITableViewCell changes in height the UITextView also changes in height.
For constraint layout I use a PureLayout (https://github.com/smileyborg/PureLayout) so the following constraint layout code may be unusual for you:
#pragma mark - Init
- (id)initWithStyle:(UITableViewCellStyle)style
reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style
reuseIdentifier:reuseIdentifier];
if (self)
{
[self.contentView addSubview:self.textView];
}
return self;
}
#pragma mark - AutoLayout
- (void)updateConstraints
{
[super updateConstraints];
/*-------------*/
[self.textView autoPinEdgeToSuperviewEdge:ALEdgeLeft
withInset:10.0f];
[self.textView autoPinEdgeToSuperviewEdge:ALEdgeTop
withInset:5.0f];
[self.textView autoPinEdgeToSuperviewEdge:ALEdgeBottom
withInset:5.0f];
[self.textView autoSetDimension:ALDimensionWidth
toSize:200.0f];
}
Inspired by the two previous answers, I found a way to solve my problem. I think the fact that I had a UITextView was causing some troubles with autoLayout. I added the following two functions to my original code.
- (CGFloat)textViewHeightForAttributedText: (NSAttributedString*)text andWidth: (CGFloat)width {
UITextView *calculationView = [[UITextView alloc] init];
[calculationView setAttributedText:text];
CGSize size = [calculationView sizeThatFits:CGSizeMake(width, FLT_MAX)];
return size.height;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
UIFont *font = [UIFont systemFontOfSize:14.0];
NSDictionary *attrsDictionary = [NSDictionary dictionaryWithObject:font forKey:NSFontAttributeName];
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:self.sampleStrings[indexPath.row] attributes:attrsDictionary];
return [self textViewHeightForAttributedText:attrString andWidth:CGRectGetWidth(self.tableView.bounds)-31]+20;
}
where in the last line 31 is the sum of my constraints to the left and right sides of the cell and 20 is just some arbitrary slack.
I found this solution while reading this this very interesting answer.
The trick to immediately update the tableview cells height in a smooth way without dismissing the keyboard is to run the following snippet to be called in the textViewDidChange event after you set the size of the textView or other contents you have in the cell:
[tableView beginUpdates];
[tableView endUpdates];
However this will may not be enough. You should also make sure the tableView has enough elasticity to keep the same contentOffset. You get that elasticity by setting the tableView contentInset bottom. I suggest this elasticity value to be at least the maximum distance you need from the bottom of the last cell to the bottom of the tableView. For instance, it could be the height of the keyboard.
self.tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardHeight, 0);
For more details and some useful extra features around this matter please check out the following link:
Resize and move UITableViewCell smoothly without dismissing keyboard
The solution almost everyone suggested is the way to go, I will add only a minor improvement. As a recap:
Simply set the estimated height, I do it via storyboard:
Make sure you have the constraints for the UITextView correctly set within the cell.
In the func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
I simply call:
cell.myTextView.sizeToFit()
Previously beginUpdates/endUpdates were the advertised solution.
Since iOS 11, performBatchUpdates is what has been recommended source.
Calling performBatchUpdates after making a change to a cell's content works for me.
Check out the Objective C solution I have provided in the following link below.
Simple to implement, clean, and no need for auto layout. No constraints needed. Tested in iOS10 and iOS11.
Resize and move UITableViewCell smoothly without dismissing keyboard
I try to make UICollectionView with cells, that intersect and partially overlay each other as it is done at screenshot:
This layout was reached by setting
self.minimumLineSpacing = -100;
at my UICollectionViewFlowLayout subclass.
When I scroll down, everything is OK. I see what I want. But when I scroll up, I see another behaviour, not like I expected:
So my question is: how can I make my layout look as at the first screen regardless scroll view direction.
Note: I have to support both iOS 6 and 7.
Thanks very much for any advices and any help.
Hmm, interesting. Since the collection view recycles cells, they are continuously added to and removed from the view hierarchy as they move on and off the screen. That being said, it stands to reason and when they are re-added to the view, they are simply added as subviews meaning that when a cell gets recycled, it now has the highest z-index of all of the cells.
One fairly pain-free way to rectify this would be to manually adjust the z position of each cell to be incrementally higher with the index path. That way, lower (y) cells will always appear above (z) the cells above (y) them.
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellID = #"CELLID";
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellID forIndexPath:indexPath];
if (cell.layer.zPosition != indexPath.row) {
[cell.layer setZPosition:indexPath.row];
}
return cell;
}
Found another sollution to solve this problem. We need to use UICollectionViewFlowLayout subclass.
#interface MyFlowLayout : UICollectionViewFlowLayout
#end
#implementation MyFlowLayout
- (void)prepareLayout {
[super prepareLayout];
// This allows us to make intersection and overlapping
self.minimumLineSpacing = -100;
}
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
NSArray *layoutAttributes = [super layoutAttributesForElementsInRect:rect];
for (UICollectionViewLayoutAttributes *currentLayoutAttributes in layoutAttributes) {
// Change zIndex allows us to change not only visible position, but logic too
currentLayoutAttributes.zIndex = currentLayoutAttributes.indexPath.row;
}
return layoutAttributes;
}
#end
Hope that helps someone else.
- (void)reloadUI
{
[_createNoteView layoutSubviews];
if (_list.is_archived == 0) {
_tableview.tableHeaderView = _createNoteView;
}
[_tableview reloadData];
}
I have a resizable input view called _createNoteView,[_createNoteView layoutSubviews] will correct its own frame.
each time content of _createNoteView was changed reloadUI will called.
I expect _createNoteView will will resize while I'm typing in it. But things won't work in iOS 7;
Everything works well on iOS 6 with the same context;
As your question is not very much clear, this is a general answer.
Have you used this tableview delegate method
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{
return 60;
}
You can calculate the size of header in this method and return the specific height
The previous one is for tableview section's header.
May be this could also help
tableView.tableHeaderView = nil;
tableView.tableHeaderView = your_headerView;
I'm making a simple UICollectionView with a paging mechanism enabled, and everything works fine. Though, when scroll to the last page the number of the cells are not fully visible in the screen, and the last page contains some cells of the previous page.
How do I expand the contentSize of the UICollectionView so that the last page doesn't contain any cells of the previous page?
An example here: the UICollectionView scrolls horizontally with 6 cells, this way:
Page 1:
cell0 - cell1 - cell2 - cell3
Page 2:
cell4 - cell5 is expected, but unexpectedly
cell2 - cell3 - cell4 - cell5
How to change it?
SUMMARY:
I want to set
collectionView.contentSize = numberOfPage * collectionView.frame
NOT
collectionView.contentSize = numberOfCell * (cellFrame + spacing)
You need to subclass UICollectionViewLayout and override the collectionViewContentSize method. I subclassed UICollectionViewFlowLayout so I wouldn't have to re-write all the layout code.
I'm building a 4x4 grid, so my method looks like this:
- (CGSize)collectionViewContentSize
{
NSInteger itemCount = [self.collectionView numberOfItemsInSection:0];
NSInteger pages = ceil(itemCount / 16.0);
return CGSizeMake(320 * pages, self.collectionView.frame.size.height);
}
Side note, when you use a custom layout, you lose the ability to set the some of the display properties in the Interface Builder. You can set them programatically in the init method of your custom UICollectionViewLayout subclass. Here's mine for reference:
- (id)init
{
self = [super init];
if (self) {
[self setup];
}
return self;
}
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super init];
if (self) {
[self setup];
}
return self;
}
- (void)setup
{
self.itemSize = CGSizeMake(65.0f, 65.0f);
self.minimumLineSpacing = 15;
self.sectionInset = UIEdgeInsetsMake(7.5f, 7.5f, 30.0f, 7.5f);
[self setScrollDirection:UICollectionViewScrollDirectionHorizontal];
}
For horizontal paging
if(CollectionView.pagingEnabled)
{
int numberOfPages = floor(collectionView.contentSize.width /
collectionView.frame.size.width) + 1;
CGFloat
float requierdWidth=self.collectionView.frame.size.width*numberOfPages;
self.Layout.footerReferenceSize=CGSizeMake(requierdWidth-self.collectionView.contentSize.width,0);
}
The answer works well, though for our code we had one section per page. So it meant the override for our layout class was just
-(CGSize) collectionViewContentSize {
return CGSizeMake(CGRectGetWidth(self.collectionView.frame) *
[self.collectionView numberOfSections],
CGRectGetHeight(self.collectionView.frame)) ;
}
I think you have to subclass UICollectionViewLayout and create your custom layout to manage these kind of problems.
I have an answer that doesn't require any subclassing.
In -viewDidLoad, calculate how many items per page you will have and how many pages you will have. Store these values in properties.
self.numberOfItemsPerPage = NumberOfRows * NumberOfColumns;
self.numberOfPages = ceilf((CGFloat)self.items.count / (CGFloat)self.numberOfItemsPerPage);
Then in -collectionView:numberOfItemsInSection: just lie to it:
return self.numberOfItemsPerPage * self.numberOfPages;
You will of course have more cells than content, right? So in -collectionView:cellForItemAtIndexPath: just return nil for the extra cells:
if (indexPath.item > [self.items count] - 1) {
//We have no more items, so return nil. This is to trick it to display actual full pages.
return nil;
}
There you go: full, scrollable final page. In my opinion, the horizontal scroll mode should just default to this.
You can adjust the content with the viewDidLayoutSubviews: method. This method gets called when the collection view and all the cells are placed in the view, so that you can adjust cell.
SUMMARY
Given that we don't always know what the frame of a cell or its content view is going to be (due to editing, rotation, accessory views etc.), what is the best way to calculate the height in tableView:heightForRowAtIndexPath: when the cell contains a variable height text field or label?
One of my UITableViewController's contains the following presentation:
UITableViewCell with UITextView.
UITextView should be the same width and height as UITableViewCell.
I created the UITableViewCell subclass, and then and initialized it with UITextView (UITextView is a private field of my UITableViewController)
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *CellIdentifier = #"TextViewCell";
UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[BTExpandableTextViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier textView:_notesTextView] autorelease];
}
return cell;
}
I implemented the following method in my UITableViewCell subclass:
- (void)layoutSubviews{
[super layoutSubviews];
CGFloat height = [textView.text sizeWithFont:textView.font constrainedToSize:CGSizeMake(textView.frame.size.width, MAXFLOAT)].height + textView.font.lineHeight;
textView.frame = CGRectMake(0, 0, self.contentView.frame.size.width, (height < textView.font.lineHeight * 4) ? textView.font.lineHeight * 4 : height);
[self.contentView addSubview:textView];
}
and of course i implemented the following UITableViewDataSource method (look! I am using self.view.frame.size.width (but really i need UITableViewCell contentView frame width):
- (CGFloat)tableView:(UITableView*)tableView heightForRowAtIndexPath:(NSIndexPath*)indexPath{
CGFloat height = [_notesTextView.text sizeWithFont:_notesTextView.font
constrainedToSize:CGSizeMake(self.view.frame.size.width, MAXFLOAT)].height;
CGFloat groupedCellCap = 20.0;
height += groupedCellCap;
if(height < [BTExpandableTextViewCell minimumTextViewHeightWithFont:_notesTextView.font]){
height = [BTExpandableTextViewCell minimumTextViewHeightWithFont:_notesTextView.font];
}
return height;
}
also I implemented the following method (thats not so important but ill post it anyway, just to explain that cell's height is dynamical, it will shrink or expand after changing text in UITextView)
- (void)textViewDidChange:(UITextView *)textView{
CGFloat height = [_notesTextView.text sizeWithFont:_notesTextView.font
constrainedToSize:CGSizeMake(_notesTextView.frame.size.width, MAXFLOAT)].height;
if(height > _notesTextView.frame.size.height){
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
}
And now, my question is:
After loading view, UITableViewController is calling methods in the following order: (ill remove some, like titleForHeaderInSection and etc for simplification)
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
- (CGFloat)tableView:(UITableView*)tableView heightForRowAtIndexPath:(NSIndexPath*)indexPath{
and only then
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
Look! I should return the correct UITableViewCell height before cellForRowAtIndexPath!
That means: I don't know UITableViewCell contentView frame. And i can't get it programmatically.
This width can be one of:
iPhone plain table, portrait orientation
iPhone plain table, landscape orientation
iPhone grouped table, portrait orientation
iPhone grouped table, landscape orientation
and the same for the iPad ( another 4 values )
And don't forget that contentView frame can be smaller because of UITableViewCell accessoryType, or because of UITableView editing state. (for example if we have UITableViewCell with multiline UILabel of any height in any editing state and with any accessoryView)
So this problem is fundamental: I just can't get cell contentView frame width for constraining, because I should return this height before cell layouts contentView. (And this is pretty logical, by the way) But this contentView frame really matters.
Of course sometimes I can know this width exactly and "hardcode" it
(for example: UITableViewCellAccessoryDisclosureIndicator has 20 px width, and tableView cannot be in editing state, then I can write self.view.frame.size.width - 20 and the task is done)!
Or sometimes contentView is equal to UITableViewController's view frame!
Sometimes I'm using self.view.frame.width in -tableView:heightForRowAtIndexPath: method.. (like now, and it works pretty well, but not perfectly because of grouped UITableView, should subtract some constant values, and they are different for 2 devices * 2 orientations)
Sometimes I have some #defined constants in UITableViewCell (if I know width exactly)...
Sometimes I'm using some dummy pre-allocated UITableViewCell (what is just stupid, but sometimes is pretty elegant and easy for use)...
But I don't like anything of that.
What's the best decision?
Maybe i should create some helper class, that will be initialized with such parameters:
accessory views, device orientation, device type, table view editing state, table view style (plain, grouped), controller view frame, and some other, that will include some constants (like grouped tableView offset, etc) and use it to find the expected UITableViewCell contentView width? ;)
Thanks
Table view uses the tableView:heightForRowAtIndexPath: method to determine its contentSize before creating any UITableViewCellcells. If you stop and think about it, this makes sense, as the very first thing you would do with a UIScrollView is set its contentSize. I have run into a similar problem before, and what I've found is that it is best to have a helper function that can take the content going into the UITableViewCell and predict the height of that UITableViewCell. So I think you will want to create some sort of data structure that stores the text in each UITableViewCell, an NSDictionary with NSIndexPaths as keys and the text as values would do nicely. That way, you can find the height of the text needed without referencing the UITableViewCell.
Although you can calculate heights for labels contained in table view cells, truly dynamically, in '- layoutSubviews' of a UITableViewCell subclass, there's no similar way of doing this (that I know of) for cell heights in '- tableView:heightForRowAtIndexPath:' of a table view delegate.
Consider this:
- (void)layoutSubviews
{
[super layoutSubviews];
CGSize size = [self.textLabel.text sizeWithFont:self.textLabel.font
constrainedToSize:CGSizeMake(self.textLabel.$width, CGFLOAT_MAX)
lineBreakMode:self.textLabel.lineBreakMode];
self.textLabel.$height = size.height;
}
Unfortunately though, by the time '- tableView:heightForRowAtIndexPath:' is called, that is too early, because cell.textLabel.frame is yet set to CGRectZero = {{0, 0}, {0, 0}}.
AFAIK you won't be able to do this neither with content view's frame, nor summing up individual labels' frames...
The only way I can think of is to come up with a convenience class, methods, constants, or such that will try to cover up all possible width in any device orientation, on any device:
#interface UITableView (Additions)
#property (nonatomic, readonly) CGFloat padding;
#end
#implementation UITableView (Additions)
- (CGFloat)padding
{
if (self.formStyle == PTFormViewStylePlain) {
return 0;
}
if (self.$width < 20.0) {
return self.$width - 10.0;
}
if (self.$width < 400.0 || [[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
return 10.0;
}
return MAX(31.0, MIN(45.0, self.$width * 0.06));
}
#end
Also note that, recently we also have new iPhone 5's 4-inch width (568 instead of 480) in landscape orientation.
This whole thing is pretty disturbing, I know... Cheers.