I am facing a crashing problem in cellForRowAtIndexPath tableview delegate method
#interface EventListView : UIViewController <UITableViewDelegate, UITableViewDataSource>
IBOutlet UITableView *tblView;
NSMutableArray *arr_EventValues,*arr_Event_Details;
NSMutableArray *arr_EventListDetails;
#property(nonatomic, retain)NSMutableArray *arr_EventValues,*arr_EventListDetails, *arr_Event_Details;
#property(nonatomic, retain)UITableView *tblView;
- (void)viewDidLoad
{
appdelegate = (VibesGuideAppDelegate *)[[UIApplication sharedApplication] delegate];
ViewCalendar = [[CalendarView alloc] initWithNibName:#"CalendarView" bundle:[NSBundle mainBundle]];
[self.navigationController.navigationBar setHidden:YES];
self.arr_Event_Details = [[NSMutableArray alloc] init];
self.arr_EventValues = [[NSMutableArray alloc] init];
[super viewDidLoad];
}
// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if ([self.arr_EventListDetails count] > 0)
{
return [self.arr_EventListDetails count];
}
return 0;
}
-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
// ------------------------------- Custom cell ------------------------------
Customcell *cell = (Customcell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
cell = [[[Customcell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
cell.textLabel.text = #"Hello";
return cell;
}
* -[EventListView tableView:cellForRowAtIndexPath:]: message sent to deallocated instance 0x60e01b0 and I used tableview from xib and set all connections and also got arrayvalues in numberOfRowsInSection in method but in cellForRowAtIndexPath method is not called so please give me idea my issue....
Thanks in advance.
At first it seems your some variable gets released. Make sure you have properly allocated it. If you have declared #property for it you better use the variable as self.variable. You can use retain and in case of IOS 5 strong in property declaration.
Just to be sure you can track if any variable gets released via setting NSZombieEnabled to YES. With zombies enabled, messages to deallocated objects will no longer behave strangely or crash in difficult-to-understand ways, but will instead log a message and die in a predictable and debugger-breakpointable way. You can set NSZombieEnabled by the following steps.
Select Product from the menu bar above. Keep alt/option pressed and select "Test..." or "Run...". Go to the Arguments tab, and add NSZombieEnabled YES in the "Environment Variables" section.
Your tableview itself is already released - the error message says that you send the cellForRowAtIndexPath message to a deallocated instance of the table view - so your problem lies somewhere in not retaining or releasing the EventListView and cannot be seen in the code displayed here.
Check this one:
Table DataSource and delegate is set or not.
Used array in cellForRowAtIndexPath is properly set with property and synthesized as well used with self. name.
First of all you dequeue the cell and then create a new one. This is not a good practice, if you are able to dequeue a cell you should not create a new one. You should have something like this:
Customcell *cell = (Customcell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil)
{
cell = [[[Customcell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
}
fix this and let me know if you are still running on the same problem.
Related
I am having an issue pushing my view controller from a tableview that was dropped into a viewController, and not a TableViewController.
I have found a thread on here with a solution here
pushViewController is not pushing
The problem is.. I have done his solution and my view still does not push. I have connected my tableview via ctrl+drag to the view controller and set both the dataSource and delegate. In the post i mentioned, they say the solution was to 'create a referencing outlet from the tableview to the view controller.' But I don't exactly know what that means. So help with that would be good as well. I have followed this tutorial and am stuck on step 9 obviously.
The line of code not triggering is
[self.navigationController pushViewController:facility animated:YES];
My code is as follows...
viewTable methods
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"list Size: %#",list);
return [list count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = (UITableViewCell *) [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
CustomerListData *customer = [self.list objectAtIndex:indexPath.row];
cell.textLabel.text = customer.facilityName;
// cell.textLabel.text = #"Detail";
return cell;
}
-(void)setValue:(NSMutableArray*)array
{
//NSMutableArray *newArray = [[NSMutableArray alloc] init];
list = array;
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
FacilityMissionListViewController *facility = [self.storyboard instantiateViewControllerWithIdentifier:#"facilityMissionList"];
[self.navigationController pushViewController:facility animated:YES];
//UINavigationController* navController = self.navigationController;
}
the very last commented out line is there to check if navigationcontroller was null. It is not.
From what I have gathered the issue here lies in the fact the table view is inside the view controller and its not a "tableviewcontroller." This method apparently works if that is the case, but some other steps must be taken if not.. but I don't know them.
Thanks in advance.
It sounds like your NavigationController is not set up correctly. Could you post the code that sets it up?
Put a :
NSLog(#"%#", self.navigationController);
in your didSelectRowAtIndexPath method and you'll see if the method is being called and if the navigationController is nil. It might be one of this cases.
Otherwise make sure that the FacilityMissionListViewController is not nil either.
I'm having a problem with my iPhone app crashing when I scroll down on a UITableView. I set NSZombieEnabled to YES, and found out that the NSArray I'm using to fill the table is getting dealloced somehow.
#import "RootViewController.h"
#implementation RootViewController
#synthesize flashsets;
- (void)viewDidLoad
{
//Unrelated code removed from this post
NSString *listofsetsstring = [[NSString alloc]
initWithContentsOfFile:pathtosetsdata
encoding:NSUnicodeStringEncoding
error:&error];
flashsets = [listofsetsstring componentsSeparatedByString:#"\n"];
[super viewDidLoad];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [flashsets count];
}
// Customize the appearance of table view cells.
- (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] autorelease];
}
// Configure the cell.
NSLog(#"IndexPath.row = %i", indexPath.row);
cell.textLabel.text = [flashsets objectAtIndex:indexPath.row]; <<<< CRASH HERE!!
return cell;
}
#end
I'm getting message sent to deallocated instance 0x4ebae20 at the bolded line. In my .h I used #property (nonatomic, retain) NSArray *flashsets;, I thought the retain part should keep it from deallocating.
How do I keep it from doing this?
Problem is with :
flashsets = [listofsetsstring componentsSeparatedByString:#"\n"];
change it to
flashsets = [[listofsetsstring componentsSeparatedByString:#"\n"] retain];
edit: the retain in property is only used if you use the setter, so it will only work if you use the following line:
[self setFlashsets:[listofsetsstring componentsSeparatedByString:#"\n"]];
in you viewDidLoad it should be self.flashsets = this will insure the accessor method is used to set the value, and thus the 'retain' behaviour you specified on the property definition will be implemented.
flashsets = [listofsetsstring componentsSeparatedByString:#"\n"];//it returns autorealesed NsArray.So If you want Longer Use.you should get Owner ship from that array By Alloc or Copy Or Retain.
flashsets = [[listofsetsstring componentsSeparatedByString:#"\n"] retain];
or
flashsets = [[listofsetsstring componentsSeparatedByString:#"\n"]copy];
or
flashsets = [[NsArry alloc ] initWithArray:[listofsetsstring componentsSeparatedByString:#"\n"]];
I don't know if this will help, but you may want to use the setter and getter methods when referring to flashsets - the retain part of the property doesn't apply (I don't think) when setting the variable directly.
have seen similar questions but couldn't find a definitive answer.
Having mastered regular tables of most types, I am doing some conceptual experiments with custom table cells to get familiar with how this works. I want to have a custom subclass of UITableViewCell which loads a nib to the contentView. I may want to implement different editing styles at some later point but want to reuse the custom view in different parts of my application, however, i'm having problem receiving the didSelectRowAtIndexPath message in my calling UITableViewController.
Here's the hierarchy which is built from a basic view template.
CustomCellViewController: A stock XCode objective-c class sublcassed from UITableViewCell
#interface CustomCellViewController : UITableViewCell {
IBOutlet UILabel *lbl;
}
#property (nonatomic, retain) IBOutlet UILabel *lbl;
#end
#implementation CustomCellViewController
#synthesize lbl;
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
// Initialization code
NSArray *a = [[NSBundle mainBundle] loadNibNamed:#"customCellView" owner:self options:nil];
UITableViewCell *tc = [a objectAtIndex:0];
NSLog(#"Cell loaded from nib");
[self.contentView addSubview:tc];
}
return self;
}
.. the other stock methods are unchanged ..
#end
I realise that the init method could be simplified but this is my first attempt.
The XIB file's owner is my custom class (CustomCellViewController), has a UITableViewCell and a label (linked to the outlet 'lbl' on it) positioned half way accross, leaving plenty of the underlying UITableViewCell clickable.
RootViewController is a standard, stock XCode subclass of UITableViewController
RootViewController sets up an instance variable "CustomTableCellController *myCustomCell"
The cellForRowAtIndexPath: is as follows:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"myCustomCell";
CustomCellViewController *cell = (CustomCellViewController *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[CustomCellViewController alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
NSLog(#"Creating New cell for position %d", indexPath.row);
} else {
NSLog(#"Reusing cell for position %d", indexPath.row);
}
// Configure the cell.
cell.lbl.text = [NSString stringWithFormat: #"Hi There %d", indexPath.row];
return cell;
}
And in the same RootViewController.m, my didSelectRowAtIndexPath:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Cell tapped at row %d", indexPath.row);
/*
<#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:#"<#Nib name#>" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
*/
}
Designed at present, to purely output a log message when tapped.
numberOfSectionsInTableView returns 1
numberOfRowsInSection returns 50
This all compiles and runs fine, iPhone simulator starts, I see a table on the display, my output log confirms it has created 9 versions of CustomCellViewController and I can see the reuse stack via the NSLog() comments.
I just can't select a row, doesn't matter where I click in the custom cell, nothing gets to my didSelectRowAtIndexPath: in my RootViewController which is where I expect it.
Is it that I have I not set a delegate somewhere and if so, how? Do I need to do this via a first responder? (ie, create a method in my CustomCellViewController class, link the UITableViewCell from the XIB to that method and then call [super didSelectRowAtIndexPath] - but how do I pass the indexPath?
Am I not responding to a message from my XIB in it's owner and then passing it on (is this how I do it?)
I read through all the apple docs to get to this stage but couldn't quite decipher how touch messaging happened.
Slightly confused!
May be you have forget to set data source and delegate if the tableview object set it as like below
tbl.delegate = self;
tbl.dataSource = self;
Just a quick question really:
I'm running a method to pull records from an sqlite database into an array, then assigning the contents of that array to an instance variable.
#interface {
NSArray *items;
}
#implementation
// The population method.
-(void)populateInstanceVariable
{
NSMutableArray *itemsFromDatabase = [[NSMutableArray alloc] init];
// Sqlite code here, instantiating a model class, assigning values to the instance variables, and adding this to the itemsFromDatabase Array.
self.items = itemsFromDatabase;
[itemsFromDatabase release];
}
// viewDidLoad is calling the method above
-(void)viewDidLoad
{
[self populateInstanceVariable];
[super viewDidLoad];
}
// TableViewDataSource method - cellforIndexPath
- (UITableViewCell *)tableView:(UITableView *)passedInTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault];
// Load in my model from the instance variable - ***1
MyDataModel *model = [items objectAtIndexPath:indexPath.row];
// Assign the title to the cell from the model data
cell.textLabel.text = model.title;
// This is the part i'm stuck on, releasing here causes a crash!
[model release];
return cell;
}
#end
My question is two fold:
Is what i'm doing to assign data to the instance variable right? and am i managing the memory correctly?
How do i manage the memory for that model item in the tableview datasource? the only way i seem to be able to get it to run smoothly is if i don't release the *model object at all, but that causes leaks surely?
Cheers.
No, you're not managing memory correctly here:
you should use "reusable" UITableViewCells, most UITableView examples show how to do this, and
do not do [model release], you do not "own" the object in this case, you're just referring to it so you must not release it
Here's the typical cellForRowAtIndexPath:
-(UITableViewCell *) tableView:(UITableView *)atableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"CellIdentifier";
// Dequeue or create a cell of the appropriate type.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier] autorelease];
// settings that do not change with every row
cell.selectionStyle = UITableViewCellSelectionStyleGray;
}
// settings that change with every row
cell.textLabel.text = #"fill in your label here";
return cell;
}
Also, if you're using a DB for your data, you may want to look in to Core Data, Apple's data persistence/management framework, it includes the ability to hook aspects of your data entities directly up to UITableViews.
1) Populate method is correct. Don't forget to set the instance variable to nil in the dealloc. (I suppose you added a property/synthesize as you used the 'self.').
2) Do NOT release the model object. You did not retain, copy or allocated it in that method. By the other hand your initialization of the cell is wrong. Use the following: (Better for performance)
- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *Identifier = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:Identifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:Identifier] autorelease];
}
//Other code
}
I'm using indexPath.row do determine in which row of my tableview I do something. The title of my cells is containing a number which should be 1 in the first row and 18 in the last row, so I have 18 rows. This works for the first 11 rows, but after that, I have numbers in the title which seem to be generated randomly! Sometimes 16, then 5, then 18, then 12... and so on.
What's the problem with it/why does the indexPath.row variable behave like that?
My cellForRowAtIndexPath method:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *MyIdentifier = #"MyIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil) {
[[NSBundle mainBundle] loadNibNamed:#"myCell" owner:self options:nil];
cell = cell0;
self.cell0 = nil;
}
UILabel *label;
label = (UILabel *)[cell viewWithTag:1];
label.text = [NSString stringWithFormat:#"Cell %d", indexPath.row];
return cell;
}
Any more suggestions on how to solve the problem? I didn't get it working until now...
// Update with more code:
Here is how I declare the cell. It is in an XIB file (template "empty XIB") in which I just put the cell from the library in IB.
#interface myViewController : UITableViewController {
UITableViewCell *cell0;
}
#property (nonatomic, retain) IBOutlet UITableViewCell *cell0;
Then, at the top of the myViewController.m file:
#synthesize cell0;
My cellForRowAtIndexPath method is already posted above. It is equal to the cellForRowAtIndexPath method in the SDK documentation, and in Apple's example, it seems to work.
What are you trying to accomplish with cell0?
cell = cell0;
self.cell0 = nil;
It looks like you're creating a new cell, but somehow deciding to use an old one. The real culprit looks like the code that is loading the cell actually getting assigned anywhere.
Try just this instead:
if (cell == nil) {
cell = [[NSBundle mainBundle] loadNibNamed:#"myCell" owner:self options:nil];
}
Or perhaps:
if (cell == nil)
{
// TODO: try to avoid view controller
UIViewController *vc = [[UIViewController alloc] initWithNibName:#"IndividualContractWithResult" bundle:nil];
cell = (IndividualContractWithResult_Cell *) vc.view;
[vc release];
}
To would be easier to answer if you give the code where you create cells for your table view. It looks that there's a problem with reusing cells - you reuse previously created cells without setting a new value to it.
It sounds like you are not re-using cells but creating new ones when there are cells available. Look at the sample code for dequeueReusableCellWithIdentifier.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MyCell"];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:#"MyCell"] autorelease];
}
cell.text = <your code here>;
return cell;
}
It would seem that you're incorrectly accessing a property here:
cell = cell0;
self.cell0 = nil;
Assuming that you have an instance variable named cell0, by setting it to nil, you may be releasing it before you're ready to use it.
The proper way to do this is:
cell = self.cell0;
self.cell0 = nil;
This way, if cell0 is declared as retain, you'll automatically get an autoreleased cell0 back, whereas if you reference cell0 directly (no self.), you'll get an unretained reference, which will disappear when self.cell0 = nil is called.
The advantage of using a nib-based cell here is that you can use outlets, rather than tags, to identify subviews. You've done the heavy lifting already, you might want to just add an outlet and subclass UITableViewCell to get access to the label.
You will need to retain and autorelease cell0, otherwise when you set self.cell0 = nil, then cell0 has no known references.
cell = [[cell0 retain] autorelease];
self.cell0 = nil;
You can also do this:
cell = self.cell0;
self.cell0 = nil;
.. Since any retain properties should implement their getters with the retain/autorelease pattern.