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;
}
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've used sqlite in my project and I get ten elements in _mChats (array) successfully. The numberOfRowsInSection method returns 10 but cellForRowAtIndexPath ignores the first few rows and in simulator other elements all display on the same cell,why?
And if I use sections instead of rows to display data,everything becomes normal.
This is my code:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [_mChats count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
VChat *cell = [VChat vChatWithTableView:tableView];
cell.mChat = _mChats[indexPath.section];
return cell;
}
I think its because of this
cell.mChat = _mChats[indexPath.section];
Try this instead
cell.mChat = _mChats[indexPath.row];
This is because Indexpath is a property that has two values inside it,
Eg. IndexPath [section,row] meaning indexpath of something is section number 1, row number 5.
Hope this helps you understand.
This is how your cellForRowAtIndexPath should look like:
- (UITableViewCell *)tableView:(UITableView *)iTableView cellForRowAtIndexPath:(NSIndexPath *)iIndexPath {
NSString *cellIdentifier = #"myCell";
UITableViewCell *cell = (UITableViewCell *)[iTableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifier];
}
cell.mChat = _mChats[indexPath.row];
return cell;
}
- (UITableViewCell *)tableView:(UITableView *)iTableView cellForRowAtIndexPath:(NSIndexPath *)iIndexPath
{
VChat *cell = (VChat *)[tableViewdequeueReusableCellWithIdentifier:#"CellIdentifier"];
NSArray *nib = [[NSBundle mainBundle]loadNibNamed:#"VChat" owner:self options:nil];
if (cell==nil)
{
cell = nib[0];
}
cell.mChat = _mChats[indexPath.row];
return cell;
}
The three delegate method must be implement you have wrote have something wrong. As #Abhinav said the method return cell have some thing wrong.
As the code you showed will create a new cell when a new cell present in the screen. I think the first few rows just because the cell has't be reused.
There is another thing I want to say, if you are using storyboard to build the tableview this method should seems like:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// The identifier in storyboard you setted.
static NSString *cellName = #"theCell";
Cell *cell = [tableView dequeueReusableCellWithIdentifier:cellName];
if (dataSource_[indexPath.row]) {
// This method will bind data to view
[cell fillDataWithDict:dataSource_[indexPath.row]];
}
return cell;
}
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.
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;
}
In a VC I have 2 tableViews - 1 main and other is added in a drop down menu. From drop down menu TableView "ddTableView", I have added 5 cells in Storyboard itself as prototype cells. Each cell contains an image and a Label. Have also set identifier for each cell. Have also set Accessory Type as "Disclosure Indicator" for each cell of ddTableView.
DataSource and Delegate for mainTV is set to the VC and delegate for ddTableView is set the VC. As the rows are added within the storyboard, I didn't set any datasource for ddTableView in my VC. I managed my delegate methods like this :-
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if (tableView == ddTableView) {
// RETURNS NIL ???
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
NSLog(#"CELL Identifier = %#", cell.reuseIdentifier);
return cell;
} else {
}
}
-(void )tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (tableView == ddTableView) {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
NSLog (#" CELL Clicked of - %#", cell.reuseIdentifier);
}
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
if (tableView == ddTableView)
return 44;
else
return 60;
}
-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if (tableView == ddTableView)
return 5;
else
return [chatMsgsArr count];
}
It does call respective delegate method. For cellForRowAtIndexPath it returns cell as nil. Why so ? And on execution, I don't see any contents of the table view - table is blank. I changed the bg color of image and text color also, but yet nothing is seen on execution.
Why so ? Where I may be going wrong ?
You have to allocate the cell, the first time cellForRowAtIndexPath is called. If the cell is not allocated it would return nil as you are getting right now.
What you need to do is allocate the cell only once, the first time you enter cellForRowAtIndexPath. After that you can reuse it as you have done.
If you are planning to use the default tableViewCell your method should look as follows:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *cellIdentifier = #"your_cell_identifier_name";
if (cell == nil)
{
UITableViewCell *cell = [UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
else
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
}
//write the code to populate your cell with data here
//return the cell object
return cell;
}
Hope this helps! :)
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] ;
}
if (tableView == ddTableView) {
NSLog(#"CELL Identifier = %d", indexpath.row);
} else {
NSLog(#"CELL Identifier = %#", [chatMsgsArr objectAtIndex:indexPath.row]);
}
return cell;
}