I have the following code to create my cells in a UITableView.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 5;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier = #"futureAppointments";
FutureAppointmentsViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (nil == cell) {
[tableView registerNib:[UINib nibWithNibName:#"FutureAppointmentsViewCell" bundle:nil] forCellReuseIdentifier:CellIdentifier];
cell = [[FutureAppointmentsViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
NSUInteger position = indexPath.row;
cell.appointmentDescription.text = [NSString stringWithFormat:#"%lu. %#. %#", (unsigned long)position, #"Steve", #"10/03/"];
return cell;
}
The problems is, the first cell of the tableView is missing. It should start with 0. Steve but instead starts with 1. Steve. Also there are only 4 elements in the list instead of 5.
When I place a break point in the code, the first cell is nil.
Does anyone know what might be happening?
Put this line of code:
[tableView registerNib:[UINib nibWithNibName:#"FutureAppointmentsViewCell"
bundle:nil]
forCellReuseIdentifier:CellIdentifier];
In viewDidLoad. It doesn't belong in cellForRowAtIndexPath. Once you do this then you no longer need to check whether the cell is nil.
Change cellForRowAtIndexPath:
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier = #"futureAppointments";
FutureAppointmentsViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
NSUInteger position = indexPath.row;
cell.appointmentDescription.text =
[NSString stringWithFormat:#"%lu. %#. %#",
(unsigned long)position, #"Steve", #"10/03/"];
return cell;
}
I think I had similar problem when I was using UITableView inside UIView and initialized it in init method.
I was not able to find good explanation for that behavior, but I've found tricky solution for that - I was reloading UITableView instance from UIViewController in viewDidAppear method.
I would also like to know, why UITableView is not drawing all UITableViewCell.
Related
I'm trying to use "reloadData" method on a uitableView, it seems like it works (both dataSource method are being called) and when I debug "cellForRowAtIndexPath" the cell that it returns is the correct cell) but I can't see the cell (numberOfRowsInSection is changing and adding blank space for each new cell - So it's not seems to be a threads problem). For example, if I have in the tableView 5 "names" (my data array called "namesArray") and I add 2 there will be 5 names and 2 nil cells presented on the tableView. The problem seems to be with cellForRowAtIndexPath.
cellForRowAtIndex:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
//Creating "cellIdentifier"(NSString) with "Cell" as the value
NSString *cellIdentifier=#"Cell";
[tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:cellIdentifier];
//Creating a default cell using "cellIdentifier"(NSString)
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
if (cell==nil) {
cell=[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.textLabel.text=[namesArray objectAtIndex:indexPath.row];
//Returning cell
return cell;
}
numberOfRowsInSection:
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.namesArray.count;
}
-(void)addNameToNamesArray:(NSString*)name
{
[self.namesArray addObject:name];
NSLog(#"namesArray lastObject: %#",[self.namesArray lastObject]);
//NSLog print: The correct name (the one that was added)
[self.tableView reloadData];
}
screenshot for "5 names and 2 nil cells":
Do you have any idea what can it be?
You call
[tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:cellIdentifier];
inside cellForRowAtIndexPath!
Don't you think that's a bit late? And if it worked, you would be calling it a bit often?
And if dequeue... returns nil when a class is registered, something is badly wrong.
change to
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
//Creating "cellIdentifier"(NSString) with "Cell" as the value
static NSString *cellIdentifier=#"Cell";
//[tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:cellIdentifier];
//Creating a default cell using "cellIdentifier"(NSString)
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell==nil) {
cell=[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.textLabel.text=[namesArray objectAtIndex:indexPath.row];
//Returning cell
return cell;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.namesArray.count;
}
set the outlet of tableview and then in addNameToNamesArray method after adding elements reload the tableview
This is likely because you have updated the data in your array, but the table view hasn't accessed that data yet, leading to the nil cells that you see. Since your cells load properly with the initial 5 element in your array, it's probable that you simply haven't refreshed the table view's data. Try using [tableView reloadData] after you have added the new elements to your array.
EDIT 1
What about changing your cellForRowAtIndexPath code to this:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
//Creating "cellIdentifier"(NSString) with "Cell" as the value
NSString *cellIdentifier=#"Cell";
//Creating a default cell using "cellIdentifier"(NSString)
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
cell.textLabel.text = [self.namesArray objectAtIndex:indexPath.row];
NSLog(#"name: %#", cell.textLabel.text);
//Returning cell
return cell;
}
Let us know the output of NSLog.
1.Make sure you have initialized self.namesArray in viewDidLoad
Try the following:
[tableView registerClass:[UITableViewCell class]forCellReuseIdentifier:cellIdentifier];
like below:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.textLabel.text = [namesArray objectAtIndex:indexPath.row];
return cell;
}
Your code is perfectly alright. There can be some possibilities that its not working for you.
You are not initialising your datasource i.e NSMutableArray in your case.
It depends how you are calling addNameToNamesArray method.
If you can share your whole code for that class as how you are calling method and every delegates you are using.
I'm adding subviews with UITableViewCell default type. In this, assume that, I've only 2 rows. At first, when it comes to tableView:cellForRowAtIndexPath: I'll generate a dynamic identifier for each cell based on indexPath.row. So it goes well and create a new cell inside if(cell == nil) condition. I'm adding subviews inside this condition only.
Next, out side that condition, I'm simply updating content of subview by fetching them out of the cell's contentView. This works great.
Problem is here : I'm expanding my cell (on which user tapped). When I do this, it'll go into tableView:cellForRowAtIndexPath: and I'm able to see the same identifier generated before. However, its going inside if(cell == nil) condition.
For a note, I'm checking for that condition like this,
if(!cell) and not if(cell == nil).
Can you guess what is the issue? However in my deep investigation, I found that, it'll only goes inside if(cell == nil) once I expand particular row and not next time for the same row.
Here's the sample :
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
//number of count
return [array count];
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
//dynamic height will be provided based on content.
return [self heightForRow:indexPath];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *cellIdentifier = [NSString stringWithFormat:#"cellIdentifier_%ld", (long)indexPath.row];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if(!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
[self setupCell:cell forRow:[indexPath row] inTable:tableView];
}
[self updateCell:cell forRow:[indexPath row] inTable:tableView];
return cell;
}
- (void) setupCell:(UITableViewCell *)cell forRow:(NSInteger)row inTable:(UITableView *)tableView {
//setting up view here
}
- (void) updateCell:(UITableViewCell *)cell forRow:(NSInteger)row inTable:(UITableView *)tableView {
//updating view here
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
self.expandedIndexPath = ([indexPath compare:self.expandedIndexPath] == NSOrderedSame) ? nil : indexPath;
[tableView beginUpdates];
[tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
[tableView endUpdates];
[tableView scrollToRowAtIndexPath:self.expandedIndexPath atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
}
Hope my issue is clear to you. Please comment if you don't get something or found anything missing here (and I'll update it here) or answer if you know what's the solution to this.
Thanks!
I'm developing an iOS 7+ app, and I've some UITableViewController in storyboard that are showing a weird behavior. I've a basic prototype cell defined in one of them, with an identifier #"standardCell" also set in storyboard. In the associated UITableViewController class, I've this:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"standardCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.textLabel.text = [NSString stringWithFormat:#"%d", indexPath.row];
return cell;
}
Cells are loaded the first tiem the table view is shown, but as soon as I scroll the table content, all cell titles that were set appear empty and cellForRowAtIndexPath: is not called anymore. The didSelectRowAtIndexPath: delegate method is neither called.
I've set both delegate and dataSource for this table view to be the table view controller. And its .h file conforms to UITableViewController <UITableViewDataSource, UITableViewDelegate>.
I find a similar issue with another table view and associated view controller, where prototype cell is a custom cell instead: cells show wrong data and weird content when I scroll the table, as if cells where not being dequeued and reused as expected.
What could I being missing?
Thanks
at least in this method:
Change this:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"standardCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.textLabel.text = [NSString stringWithFormat:#"%d", indexPath.row];
return cell;
}
To this:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"standardCell" forIndexPath:indexPath];
cell.textLabel.text = [NSString stringWithFormat:#"%d", indexPath.row];
return cell;
}
I am having issues with my tableView not firing the didSelectRowAtIndexPath method. I have implemented the delegates as such:
#interface ViewController : UIViewController<UITableViewDataSource, UITableViewDelegate,UIScrollViewDelegate>
And in my storyboard the tableView's data source and delegate are both pointed at the base View Controller. I have User Interactions enabled as well as Selection set to Single Selection, and it is not the TapGesture problem since my tap gestures are not bound to the view and I have checked and they do not fire.
This is the code for setting up the table:
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return menuArray.count;
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"menuCell"];
NSDictionary *menuItem = [menuArray objectAtIndex:indexPath.row];
cell.textLabel.text = menuItem[#"Title"];
cell.detailTextLabel.text = menuItem[#"Subtitle"];
return cell;
}
-(void)showMenu{
[UIView animateWithDuration:.25 animations:^{
[content setFrame:CGRectMake(menuTable.frame.size.width, content.frame.origin.y, content.frame.size.width, content.frame.size.height)];
}];
}
-(void)hideMenu{
[UIView animateWithDuration:.25 animations:^{
[content setFrame:CGRectMake(0, content.frame.origin.y, content.frame.size.width, content.frame.size.height)];
}];
}
-(IBAction)showMenuDown:(id)sender {
if(content.frame.origin.x == 0)
[self showMenu];
else
[self hideMenu];
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
//whatever
}
The table is initially out of view on the storyboard (origin.x is set to -150), then when the user clicks on a button in the navigationBar, the view slides over to reveal it, which is what might be causing the problem I think.
Is there anything wrong with my code or implementation that would be causing this to not work?
If you already see your table populated with values from your dictionary then you can rule out data source and delegate as being the problem. i.e. your storyboard connections are working.
Your code looks fine to me. the only difference I see is I usually define my table like this. Try this and see if it helps.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
//NSLog(#"Inside cellForRowAtIndexPath");
static NSString *CellIdentifier = #"Cell";
// Try to retrieve from the table view a now-unused cell with the given identifier.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// If no cell is available, create a new one using the given identifier.
if (cell == nil)
{
// Use the default cell style.
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
//Your code here
// ....
return cell;
}
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"menuCell"];
This will return nil in case there was never a cell created.
so checking if cell is nil is mandatory and if so, you need to create a cell.
static NSString *CellIdentifier = #"menuCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil) {
cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
}
as you are using storyboard you can alternatively use
UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
for prototype cells. Make sure you use the same identifier in the storyboard and that you registered your the cell's class
- (void) viewDidLoad {
[super viewDidLoad];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"menuCell"];
}
I don't know what I am doing wrong but the cellForRowAtIndexPath method of table view is getting called only once.
Here is my code:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
NSLog(#"--->%d",[collaboratoresdata count]);
return [collaboratoresdata count];
}
When my collaboratoresdata array is filled, then I am calling [_collaboratortblView reloadData] to reload the table view.
I am successfully getting 3 in NSLog(#"--->%d",[collaboratoresdata count]); but cellForRowAtIndexPath is getting called only one time.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
// add a placeholder cell while waiting on table data
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:nil] autorelease];
}
cell.selectionStyle=UITableViewCellSelectionStyleNone;
NSLog(#"tableView:%d",[indexPath row]);// i am getting 0 here than after its not calling
return cell;
}
check the height of cell i think thats the issue
please try to set height of cell manually(custom). So, if problem of cell height then it will be resolved. below method set cell height 30 pixels.
#pragma mark- TableView delegate Methods
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 30.0f;
}