The structure of my code is this:
UITableViewController (with one or more)-> Custom UITableviewCell (add the view of)-> UIViewController
Now, to notify an action on the UIViewController to the UITableViewController I have a protocol that follow the inverse flow explained before, but, when I do some action on UIViewController, app crashes because I'm trying to access to a deallocated instance...
I avoid the crash on IBAction on UIViewController in a dirty way: setting a property in the UIViewController as self
How can I solved this leak? This is my code:
UITableViewController:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
GameTableViewCell *cell;
cell = [tableView dequeueReusableCellWithIdentifier: CellId];
[cell configureWithGame: currentGame];
cell.delegate = self;
return cell;
}
Custom TableViewCell:
-(void)configureWithGame:(Game *)game
{
outcomeController = [[OutcomeViewController alloc] initWithGame:game];
outcomeController.delegate = self;
activeGame = game;
//Adapting outcomeView
CGRect frame = outcomeController.view.frame;
frame.size = self.outcomeView.frame.size;
outcomeController.view.frame = frame;
[[self.outcomeView subviews] makeObjectsPerformSelector:#selector(removeFromSuperview)];
[self.outcomeView addSubview:outcomeController.view];
}
The OutcomeViewController has a property #property (nonatomic, strong) id forceRetain; and it sets in -(void)viewDidLoad in this way:
self.forceRetain = self;
This causes some leaks and I want to solve this issue.
try setting outcomeController property to strongin your cell code.
Moreover, with the code you posted, the OutcomeViewController will be allocated every time you scroll the UITableView. Is this the behavior you want?
Related
I created a custom UITableViewCell named GateCell, inside it I placed one label and one text field.
In GateCell.h
#property (weak, nonatomic) IBOutlet UILabel *gateLabel;
#property (weak, nonatomic) IBOutlet UITextField *gateTextField;
In GateTableViewController
- (void)viewDidLoad {
[self.tableView registerClass:[GateCell class] forCellReuseIdentifier:#"cellIdentifier"];
}
Finally at cellForRowAtIndexPath method, I used like this
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
GateCell *cell = (GateCell *)[tableView dequeueReusableCellWithIdentifier:#"cellIdentifier"];
cell.gateLabel.text = #"Gate";
cell.gateTextField.text = #"Open Gate"
return cell;
}
When I print the description of the cell, I getting the following..
<`GateCell`: 0x7b6bd790; baseClass = `UITableViewCell`; frame = (0 0; 320 44); layer = <CALayer: 0x7b6c2e60>> <br>
Printing description of cell->_gateLabel:
nil
Printing description of cell->_gateTextField:
nil
Why label and textField returns nil when cell is created ???
I have previously encountered troubles when doing registerClass:forCellReuseIdentifier: and doing a dequeueReusableCellWithIdentifier: in tableView:cellForRowAtIndexPath:.
I had to replace dequeueReusableCellWithIdentifier: and directly init cells since registerClass:forCellReuseIdentifier: had been made.
Try in tableView:cellForRowAtIndexPath: this way
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
//Create your custom cell GateCell the way it has to be done providing the 'reuseIdentifier'
//With a standard UITableViewCell it should be :
//UITableViewCell* cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cellIdentifier"];
GateCell *cell = [[GateCell alloc] init];
cell.gateLabel.text = #"Gate";
cell.gateTextField.text = #"Open Gate"
return cell;
}
First thing ensure that you connected the IBOutlet from the interface builder. if not then connect the IBOutlet.
for getting a cell use the following
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cellReuseIdentifier"];
By calling
[self.tableView registerClass:[GateCell class] forCellReuseIdentifier:#"cellIdentifier"];
the table view will create a cell directly, not from a NIB file, so your IBOutlets won't be set (there is nowhere they could be set from).
Either you should be registering a NIB instead of a class or you should be creating the subviews as part of initWithStyle:reuseIdentifier:.
Your additional comments say that you're using a storyboard. In this case you should be setting the class of the cell you add in storyboard to GateCell and setting the cell identifier to cellIdentifier. Then, in code, you should remove the call to [self.tableView registerClass:[GateCell class] forCellReuseIdentifier:#"cellIdentifier"]; because making that call is replacing the storyboard registration...
UITableViewCells get emptied on scroll (Objective-C)
I am having a problem with UITableViewCells getting emptied as soon I a start to scroll within the table view.
I already had a look at Cells become empty after scrolling. (Xcode) - however the problem still persists.
1) I have a popover view controller, which presents a way to log into some administration. Upon successful login (which hasn’t been implemented yet, the LOGIN button simply takes one straight to a test tableView - which should be fed from some external database later on).
2) Upon successful login, the login view inside the popover gets removed and a custom UITableViewController comes into play with its own XIB.
3) This UITableViewController uses a custom UITableViewCell - since prototype cells are not possible within this configuration.
It all works to the point where I scroll the table - and all the cells get emptied for some reason.
Here is the code run down (I leave out the obvious, eg properties and table section, etc setups):
1) customPopUpViewController(XIB ,.h, .m):
- (IBAction)loginButtonPressed:(UIButton *)sender {
UITableViewController *libraryTableViewController = [[LibraryAdminTableViewController alloc]initWithNibName:#"LibraryAdminTableViewController" bundle:nil];
libraryTableViewController.view.frame = CGRectMake(0, 179, libraryTableViewController.view.frame.size.width, libraryTableViewController.view.frame.size.height);
[self.view addSubview:libraryTableViewController.view];
}
2) LibraryAdminTableViewController (XIB ,.h, .m):
- (void)viewDidLoad {
[super viewDidLoad];
self.LibraryAdminTable.delegate = self;
self.LibraryAdminTable.dataSource = self;
self.tblContentList = [[NSMutableArray alloc]init];
self.tblContentList = [NSMutableArray arrayWithObjects:#"Sync Pack 1",#"Sync Pack 2",#"Sync Pack 3", nil];
[self.LibraryAdminTable registerNib:[UINib nibWithNibName:#"LibraryAdminTableViewCell" bundle:[NSBundle mainBundle]] forCellReuseIdentifier:#"LibraryAdminCell"];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
LibraryAdminTableViewCell *cell = [self.LibraryAdminTable dequeueReusableCellWithIdentifier:#"LibraryAdminCell" forIndexPath:indexPath];
NSString* trackList = [self.tblContentList objectAtIndex:indexPath.row];
cell.cellLabel.text = trackList;
return cell;
}
3) LibraryAdminTableViewCell (XIB ,.h, .m) - I gave the Identifier in the Attributes Inspector “LibraryAdminCell”:
#property (strong, nonatomic) IBOutlet UILabel *cellLabel;
What am I missing?
It is solved. According to this thread I had to get a strong reference to the custom UITableViewController via a property in the popup controller since the ViewController (being the DataSource for the tableView) would not be retained in memory.
This is happening because you are not creating a new cell, when tableview will try to dequeue a cell, and it does not get the cell, then it should create the cell to use but you are not creating any cell, so it is returning nil.Try the code below
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
LibraryAdminTableViewCell *cell = (LibraryAdminTableViewCell*)[self.LibraryAdminTable dequeueReusableCellWithIdentifier:#"LibraryAdminCell"
forIndexPath:indexPath];
if (cell == nil)
{
cell = [[LibraryAdminTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"LibraryAdminCell"];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
}
NSString* trackList = [self.tblContentList objectAtIndex:indexPath.row];
cell.cellLabel.text = trackList;
return cell;
}
UITableView data disappears on touch, as per screen shots below
The data loads correctly when the view is first loaded, like so.
On touching the screen and then releasing, the data disappears. (If I touch and hold, the data is still present.)
I set a breakpoint in the UITableView custom class and noticed that the methods within (such as cellForRowAtIndexPath:) are called when the view is loaded, but not after touch. The didSelectRowAtIndexPath: method is never called.
The code is very similar to the DateCell example. I'm trying to load a DatePicker (configured to show time only) when a cell is touched.
The relevant code is below, along with a screenshot of the IB delegate and datasource connections. Please let me know if you need any more info. I am new to iOS, so I would greatly appreciate as much detail of possible causes and solutions as possible.
#interface ScheduleTableViewController ()
#property (nonatomic, strong) NSArray *dataArray;
#property (nonatomic, strong) NSDateFormatter *timeFormatter;
#property (nonatomic, strong) NSIndexPath *timePickerIndexPath;
#property (assign) NSInteger pickerCellRowHeight;
#property (nonatomic, strong) IBOutlet UIDatePicker *pickerView;
#property (nonatomic, strong) IBOutlet UIBarButtonItem *doneButton; //to be used later for ios 6 compatability
#end
#implementation ScheduleTableViewController
- (void)viewDidLoad
{
[super viewDidLoad];
NSMutableDictionary *itemOne = [[#{ kPeriodKey : #" Tap a cell to change the survey time: " } mutableCopy ] autorelease];
NSMutableDictionary *itemTwo = [[#{ kPeriodKey : #"Morning Survey",
kTimeKey : [NSDate date] } mutableCopy] autorelease];
NSMutableDictionary *itemThree = [[#{ kPeriodKey : #"Evening Survey",
kTimeKey : [NSDate date] } mutableCopy] autorelease];
self.dataArray = #[itemOne, itemTwo, itemThree];
self.timeFormatter = [[[NSDateFormatter alloc] init] autorelease];
[self.timeFormatter setDateFormat:#"h:mm a"];
[self.timeFormatter setDateStyle:NSDateFormatterNoStyle];
[self.timeFormatter setTimeStyle:NSDateFormatterShortStyle];
UITableViewCell *pickerViewCellToCheck = [self.tableView dequeueReusableCellWithIdentifier:kTimePickerID];
self.pickerCellRowHeight = pickerViewCellToCheck.frame.size.height;
[self.tableView setDelegate:self];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if (cell.reuseIdentifier == kDayPeriodAndTimeCellID) {
// todo check for ios < 7.0
[self displayInlineTimePickerForRowAtIndexPath:indexPath];
} else {
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = nil;
NSString *cellID = kDayPeriodAndTimeCellID;
if ([self indexPathHasPicker:indexPath]) {
cellID = kTimePickerID;
}
cell = [tableView dequeueReusableCellWithIdentifier:cellID forIndexPath:indexPath];
if (indexPath.row == 0) {
cell.selectionStyle = UITableViewCellSelectionStyleNone;
}
NSInteger modelRow = indexPath.row;
if (self.timePickerIndexPath != nil && self.timePickerIndexPath.row < indexPath.row) {
modelRow--;
}
NSDictionary *itemData = self.dataArray[modelRow];
if ([cellID isEqualToString:kDayPeriodAndTimeCellID]) {
cell.textLabel.text = [itemData valueForKey:kPeriodKey];
cell.detailTextLabel.text = [self.timeFormatter stringFromDate:[itemData valueForKey:kPeriodKey]];
}
return cell;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if ([self hasInlineTimePicker]) {
NSInteger numRows = self.dataArray.count;
return ++numRows;
}
return self.dataArray.count;
}
I am adding to an existing application, so all of the existing UI is implemented in XIB files, however this table is implemented in a storyboard. Here is a screen shot of the delegate and datasource outlet connections.
I think you need to provide a little more context here, but I have a guess. A UITableView needs a UITableViewDataSource to tell it what data should be in the cells. Do you hook that up in the XIB? If so, I don't see any of the methods implemented in your ScheduleTableViewController.
Make sure you implement that protocol and specifically the method "tableView:cellForRowAtIndexPath:". This is where you actually configure the cells that appear in the table view.
It sounds like you created the prototype table cells in InterfaceBuilder. For each prototype cell you created, make sure you set it's cell identifier in the properties inspector. Then use this cell identifier to identify which cell you are configuring in the call to "tableView:cellForRowAtIndexPath:".
Have you tried setting your table data with the functions
numberOfSectionsInTableView:tableView
tableView:tableView numberOfRowsInSection:section
I had the similar issue (in swift). It was solved by putting an instance variable to my tableViewManager responsible for presenting tableView. Initially an instance of it was created and called from button action method. So it was deallocated by ARC and consequently tableView had disappeared when I was trying to interact with it.
Inspired by: iOS TableViewController in PopOver disappears after touching tableview
In my case I was using SwipeMenuViewController (https://github.com/yysskk/SwipeMenuViewController)
and in each page there was a table view.
When I click the tabs it's switch the tables with no problem. but when I touched the table the data disappeared although
the table exists (I used background colours to check)
My solution was to hold a reference to the UIViewControllers return from the SwipeMenuViewController method:
func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewControllerForPageAt index: Int) -> UIViewController {
viewControllers[index.description] = baseContactsTableViewController
return baseContactsTableViewController
}
I have a UITableView which has another UITableView nested inside one its cells (I know this is bad practise, don't worry!).
The problem is that when I call dequeueReusableCellWithIdentifier: I am getting nil back. HOWEVER this works just fine when the UITableView is not nested inside another one.
Is there a way to NOT reuse a UITableViewCell, but instead directly instatiate it every time?
I've tried using this:
ContactFieldCell *cell = [[ContactFieldCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:thisCellIdentifier];
which doesn't return nil, but then nothing appears in my UITableView!
Here's the code for the "parent" UITableView:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"ContactCardCell";
ContactCardCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
NSArray *objects = [[sections objectAtIndex:indexPath.section] objectForKey:#"objects"];
CDCard *card = [objects objectAtIndex:indexPath.row];
cell.delegate = self;
cell.fieldsTableView = [[CardTableViewController alloc] initWithCard:card];
[cell.fieldsTableView.view setFrame:CGRectMake(17, 12, 256, 163)];
[cell.contentView addSubview:cell.fieldsTableView.view];
return cell;
}
and here's the code for the "child" UITableView:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *thisCellIdentifier = #"ContactFieldCell";
ContactFieldCell *cell = [self.tableView dequeueReusableCellWithIdentifier:thisCellIdentifier];
cell.delegate = self;
cell.field = [self.card.sortedFields objectAtIndex:indexPath.row];
return cell;
}
ContactFieldCell is a prototype cell within the storyboard. It has the following code:
#interface ContactFieldCell : UITableViewCell
#property (nonatomic, weak) id<ContactFieldCellDelegate> delegate;
#property (nonatomic, strong) CDField *field;
#property (nonatomic, strong) IBOutlet UILabel *displayNameLabel;
#end
dequeueReusableCellWithIdentifier: does not create a cell if none was found for dequeueing.
Create a cell manually, or use dequeueReusableCellWithIdentifier:forIndexPath:
Yes - #vikingosegundo is correct, but to expand his answer, you need to also register your cell first. dequeueReusableCellWithIdentifier: may return nil. And if it is you need to create your cell,s but dequeueReusableCellWithIdentifier: forIndexPath: will always return a valid cell, the catch is you need to tell it what kind of cell, that is what registerClass does.
Do this for both UITableViews.
- (void)viewDidLoad {
[super viewDidLoad];
[self.tableView registerClass:[ContactFieldCell class] forCellReuseIdentifier:#"ContactFieldCell"];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *thisCellIdentifier = #"ContactFieldCell";
ContactFieldCell *cell = [self.tableView dequeueReusableCellWithIdentifier:thisCellIdentifier forIndexPath:indexPath];
cell.delegate = self;
cell.field = [self.card.sortedFields objectAtIndex:indexPath.row];
return cell;
}
UITableViews are a very powerful element and can be used to build great apps.
The only thing to keep in mind is, the basics must be clear. Now from your code, I cannot make out whether you have assigned the delegates and dataSources properly, but I'll still mention it in case someone else needs it.
You have a subclassed UITableViewCell which in turn contains a UITableView. The UIViewController must be the delegate and dataSource for the outer UITableView. Make sure you have set it in both the .h and .m file.
Next, your custom cell must also be the delegate and dataSource, but for the inner UITablewView. I suppose here, you have created the inner UITableView in the init method of the UITableViewCell. Set the delegate and dataSource there itself. Then you set other runtime properties in the drawRect method (if needed) and call it's reloadData.
The UIViewController must override the delegate and dataSource methods for the outer table and the cell must override the methods for the inner table.
Also, make sure, the time the cells are plotted, your data is not nil or null.
And a very important fact, that people miss is the following code:
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
Just dequeueing the cell is not enough. The first time a cell is dequeued, it is nil because it has not been created yet. Hence the if condition. Once it is allocated and initialized and added to the table, the dequeue code works thereafter.
NOTE : After looking more closely to your code (sorry for not looking the first time), I noticed you have allocated a UITableViewController to your cell. How do you think the cell is going to display a controller? Use a UITableView instead. Try to follow the pattern I have mentioned in paragraph 3. Use a table in the custom cell as a private member (or property, your wish), allocate it in init. Assign the data to the cell from your view controller. Then use this data to set the inner table view cell's properties in it's drawRect. It should work fine.
I have some issues with a custom UITableViewCell and how to manage things using storyboards. When I put the styling code in initWithCoder: it doesn't work but if I put it in tableView: cellForRowAtIndexPath: it works. In storyboard I have a prototype cell with its class attribute set to my UITableViewCell custom class. Now the code in initWithCoder: does get called.
SimoTableViewCell.m
#implementation SimoTableViewCell
#synthesize mainLabel, subLabel;
-(id) initWithCoder:(NSCoder *)aDecoder {
if ( !(self = [super initWithCoder:aDecoder]) ) return nil;
[self styleCellBackground];
//style the labels
[self.mainLabel styleMainLabel];
[self.subLabel styleSubLabel];
return self;
}
#end
TableViewController.m
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"NearbyLandmarksCell";
SimoTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
//sets the text of the labels
id<SimoListItem> item = (id<SimoListItem>) [self.places objectAtIndex:[indexPath row]];
cell.mainLabel.text = [item mainString];
cell.subLabel.text = [item subString];
//move the labels so that they are centered horizontally
float mainXPos = (CGRectGetWidth(cell.contentView.frame)/2 - CGRectGetWidth(cell.mainLabel.frame)/2);
float subXPos = (CGRectGetWidth(cell.contentView.frame)/2 - CGRectGetWidth(cell.subLabel.frame)/2);
CGRect mainFrame = cell.mainLabel.frame;
mainFrame.origin.x = mainXPos;
cell.mainLabel.frame = mainFrame;
CGRect subFrame = cell.subLabel.frame;
subFrame.origin.x = subXPos;
cell.subLabel.frame = subFrame;
return cell;
}
I have debugged the code and found that the dequeue... is called first, then it goes into the initWithCoder: and then back to the view controller code. What is strange is that the address of the cell in memory changes between return self; and when it goes back to the controller. And if I move the styling code back to the view controller after dequeue... everything works fine. It's just I don't want to do unnecessary styling when reusing cells.
Cheers
After initWithCoder: is called on the cell, the cell is created and has its properties set. But, the relationships in the XIB (the IBOutlets) on the cell are not yet complete. So when you try to use mainLabel, it's a nil reference.
Move your styling code to the awakeFromNib method instead. This method is called after the cell is both created and fully configured after unpacking the XIB.