I have a UITableViewController that is duplicating rows as I scroll down. I understand that the cells are being reused, but I just can't seem to figure out what to do to fix it. I've read through other similar posts and couldn't figure out a solution in my case.
What am I doing wrong in my code that's resulting in duplicated cells?
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"StringTableViewCell";
if (indexPath.row == 0) {
cellIdentifier = #"StringTableViewCell";
} else if (indexPath.row == 1) {
cellIdentifier = #"StringTableViewFooter";
}
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
// Sets up the table view cell accordingly based around whether it is the
// string row or the footer
if (cell) {
if ([cell isKindOfClass:[StringTableViewCell class]]) {
StringTableViewCell *stringCell = (StringTableViewCell *)cell;
// Sets the photos to the array of photo data for the collection view
[stringCell setCollectionData:self.images];
} else if ([cell isKindOfClass:[StringFooterTableViewCell class]]) {
// Sets the table view cell to be the custom footer view
StringFooterTableViewCell *footerCell = [[StringFooterTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"StringTableViewCellFooter"];
// Init's the footer with live data from here
[footerCell setStringUploaderName:#"Name"];
[footerCell setStringUploadDate:#"10 minutes ago"];
[footerCell setStringUploaderProfileImage:[UIImage imageNamed:#"avatar.jpg"]];
[footerCell setCommentButtonTitle:#"4.7k"];
[footerCell setLikeButtonTitle:#"11.3k"];
return footerCell;
}
}
return cell;
}
There's a prepareForReuse method for UITableViewCell which is called every time it's about to be reused. You can set your StringTableViewCell's imageview's image to nil there or you can just do it on the cell for indexPath itself, as the prepareForReuse method is only encouraged to be used in resetting the state(like hightlighted, or selected) for the cell and it's subviews.
Since you have two different cells you need something like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == 0) {
static NSString *cellIdentifier = #"StringTableViewCell";
StringTableViewCell *stringCell = (StringTableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!stringCell) {
stringCell = [[StringTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
[stringCell setCollectionData:self.images];
return stringCell;
} else if (indexPath.row == 1) {
static NSString *cellIdentifier = #"StringTableViewFooter";
StringFooterTableViewCell *footerCell = (StringFooterTableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!footerCell) {
footerCell = [[StringFooterTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
// Init's the footer with live data from here
[footerCell setStringUploaderName:#"Name"];
[footerCell setStringUploadDate:#"10 minutes ago"];
[footerCell setStringUploaderProfileImage:[UIImage imageNamed:#"avatar.jpg"]];
[footerCell setCommentButtonTitle:#"4.7k"];
[footerCell setLikeButtonTitle:#"11.3k"];
return footerCell;
} else {
return nil; // this shouldn't happen but makes the compiler happy
}
}
Of course the code needs to be updated to show the data appropriate to the given section.
Related
I have a tableView with a custom cell. I have the posibility to save to favorites some of the elements , and when this is happening i want to add a star image in cell. I was trying doing this , but after the star appears, i have a problem . I think it's because of reusable cell but i dont know how to solve it . My problem is : stars appear again on the other cells even if the word is not added on favorites.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
dictionaryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (!cell) {
cell=[[dictionaryTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"];
}
if (tableView == self.searchDisplayController.searchResultsTableView)
{
cell.textLabel.text = [self.searchResult objectAtIndex:indexPath.row];
}
else
{
cell.word.text = self.tableData[indexPath.row];
BOOL isTheObjectThere = [self.favoriteArry containsObject:self.tableData[indexPath.row]];
if (isTheObjectThere==TRUE) {
cell.favImg.image=[UIImage imageNamed:#"3081#3x.png"];
}
}
return cell;
}
Replace following code in place of cellForRowAtIndexPath. you will get your desire output.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
dictionaryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (!cell) {
cell=[[dictionaryTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"];
}
cell.favImg.hidden = YES;
if (tableView == self.searchDisplayController.searchResultsTableView)
{
cell.textLabel.text = [self.searchResult objectAtIndex:indexPath.row];
}
else
{
cell.word.text = self.tableData[indexPath.row];
BOOL isTheObjectThere = [self.favoriteArry containsObject:self.tableData[indexPath.row]];
if (isTheObjectThere==TRUE) {
cell.favImg.hidden = NO;
cell.favImg.image=[UIImage imageNamed:#"3081#3x.png"];
}
}
return cell;
}
Hope this help you.
You have to remove the image if the object is not TRUE
if (isTheObjectThere==TRUE) {
cell.favImg.image=[UIImage imageNamed:#"3081#3x.png"];
} else {
cell.favImg.image=nil;
}
Yes, you are right it's because of reusing your cells via dequeueReusableCell with identifier as-
dictionaryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
according to your requirements you set a star image on a cell to indicate some favorite elements on the respective cell, like this
BOOL isTheObjectThere = [self.favoriteArry containsObject:self.tableData[indexPath.row]];
if (isTheObjectThere==TRUE) {
cell.favImg.image=[UIImage imageNamed:#"3081#3x.png"];
}
When any cell with star image is reused than it should be removed if the next cell does not some favorite elements but if it does have some favorite elements than it should be used as-
To resolve this issue just add the else case with the above if statement as
if (isTheObjectThere == TRUE)
cell.favImg.image=[UIImage imageNamed:#"3081#3x.png"];
else
cell.favImg.image=nil;
I'm seeking how create several cells to go to different ViewControllers.
For my TableView, I'm using a subclass of UITableViewController.
And when I choose 2 in the following method, I just see 2 identical cells which are doing exactly the same thing. I'm not interested by this. I don't even know their IndexPath in order to change their title.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return 2;
}
And When I try to put another UITableViewCell in my TableView, it doesn't appear on iOS simulator, even with the same option (same subclass) than my first UITableViewCell which I can see.
Thanks for your help.
Edit : Here is my new code to create 2 cells but doesn't work :
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell2";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[customCell alloc] init];
}
static NSString *CellIdentifier1 = #"Cell1";
UITableViewCell *cell1 = [tableView dequeueReusableCellWithIdentifier:CellIdentifier1];
if (cell1 == nil) {
cell1 = [[customCell alloc] init];
}
// Configure the cell...
return cell;
}
You define your cells in tableView:cellForRowAtIndexPath:, so you should provide an implementation for that method.
tableView:numberOfRowsInSection: only returns the number of cells in the table.
If you need more help, please provide your implementation for tableView:cellForRowAtIndexPath:. This is how a typical implementation looks like:
- (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];
}
... customize your cell ...
}
EDIT:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell2";
static NSString *CellIdentifier1 = #"Cell1";
if(indexPath.row == 0 ) {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[customCell alloc] init];
}
} else {
UITableViewCell *cell1 = [tableView dequeueReusableCellWithIdentifier:CellIdentifier1];
if (cell1 == nil) {
cell1 = [[customCell alloc] init];
}
}
return cell;
}
This method gets called when a cell has been selected. You can decide what you wanna do according to the selected row
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == 0)
[self goToFirstViewController];
else
if(indexPath.row == 1)
[self goToSecondViewController];
}
Use the following:
- (NSInteger) tableView: (UITableView*) tableView numberOfRowsInSection: (NSInteger) section
This delegate method returns the number of rows you want in that particular section. So if you want more than 2 rows, or you want the number of rows to be dynamic, you can create a NSArray in the AppDelegate or in the init method of the viewController class, and return the number in the numberOfRowsInSection method like
return [delegate numberOfNames];
In my example above, I created an array in my AppDelegate and also a method to return the number of objects I have in that array so that I can create the number of rows for my table.
- (UITableViewCell*) tableView: (UITableView*) tableView cellForRowAtIndexPath: (NSIndexPath*) indexPath
This delegate method will show what you want to display in each cell. Therefore, following on from my array created in my AppDelegate, I first create the cell, then I will set the text I want to display on the cell with a method I created in my AppDelegate that will return a NSString while taking in a NSInteger so that I can loop through my array and display the text accordingly.
static NSString* MyIdentifier = #"Default";
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if( cell == nil )
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MyIdentifier] autorelease];
cell.textLabel.text = [delegate nameAtIndex:indexPath.row];
}
nameAtIndex is the name of the method I created in my AppDelegate that will return the NSString object at the specific index (ie. the row number) from the NSArray I created to store all the items of my table.
When the user clicks on any of the rows in the table created, this delegate method will be called
- (void) tableView: (UITableView*) tableView didSelectRowAtIndexPath: (NSIndexPath*) indexPath
And in here, I will check if the text displayed matches any of the items in my array from the AppDelegate that stores the items in the table, and create the view that is necessary.
UIViewController* viewController = nil ;
NSString* nameInArray = [delegate nameAtIndex:indexPath.row] ;
if( [nameInArray isEqualToString:#"firstName"] )
{
viewController = [[FirstViewController alloc] init];
}
else if( [nameInArray isEqualToString:#"secondName"] )
{
viewController = [[SecondViewController alloc] init];
}
else if( [nameInArray isEqualToString:#"thirdName"] )
{
viewController = [[ThirdViewController alloc] init];
}
So with these 3 delegate methods, you will be able to create the table using a NSArray created, and be able to redirect the user to a viewController according to which option in the table he chooses. You will not have to keep editing the delegate methods if you choose to add more rows to the table as well since you are returning the count of the array when setting up the table.
The array and methods to get the data of the array can be created in the viewController as well, not necessarily in the AppDelegate, in case you were wondering.
The methods are as follows:
-(NSInteger) numberOfNames
{
return [myArray count];
}
-(NSString*) nameAtIndex: (NSInteger) index
{
return [myArray objectAtIndex:index] ;
}
Hope this helps! :)
I have one UIViewController with UITableView inside,above table I have UISegmentControl, when I press on segment control I want to load a UItableCustomeCell, would you please help me in this implementation, I don't know how should I add them in cellForRowAtIndexPath, Since I have 3 different Custom cell
Here is the code
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath
*)indexPath
{
if (indexPath.row == self.segmentedControl.selectedSegmentIndex == Test1) {
MytestsCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MytestsCell"];
if (!cell) {
cell = [[MyBooksCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"MytestsCell"];
}
return cell;
}
else if (indexPath.row == self.segmentedControl.selectedSegmentIndex == tests) {
testCell *cell = [tableView dequeueReusableCellWithIdentifier:#"testCell"];
if (!cell) {
cell = [[TestsCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"testsCell"];
}
return cell;
}
break;
case 1:
if (indexPath.row == self.segmentedControl.selectedSegmentIndex == PTest) {
PTestsCell *cell = [tableView dequeueReusableCellWithIdentifier:#"PTestsCell"];
if (!cell) {
cell = [[PTestsCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"PTestsCell"];
}
return cell;
}
break;
}
I don't want to have 3 of them in one table, each custom cell is for one segment control
Thanks in advance!
One alternative I can think of is to switch the table views data source. But I would not recommend that. You could define a delegate of your data source and ask it for the table view cell for a selected segmented control. But this just moves the problem. I would stick to your approach.
So...here is what I would do. Starting with iOS6, you no longer need to check if your cell is nil after dequeuing from the tableview if you use
- (id)dequeueReusableCellWithIdentifier:(NSString *)identifier forIndexPath:(NSIndexPath *)indexPath
You are guaranteed to get a cell back as long as the identifier exists. Also, it doesn't look like you need to do any additional configuration so something like this should work:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *identifier = [NSString stringWithFormat:#"%d", self.segmentedControl.selectedSegmentIndex];
return [tableView dequeueReusableCellWithIdentifier:identifier forIndexPath:indexPath];
}
Edit: I forgot to add, that in order to use this, use numbers that correspond to the segments as the identifier for each cell.
I have a TableView with data from parse.com where I Placed order to descend according to Functional queryfortable with the "Date" selected by a pickerdate. Now the earliest date turns out to be the last cell and only in the last cell I would like to add a image ... In this specific case, how could I do? This is more 'complicated for me: (
I need to insert an image only in the last cell
Thanks Rory
If you're using PFQueryTableViewController then you should be using a custom subclass of it.
/// MyPFQueryTableViewController.h
#interface MyPFQueryTableViewController : PFQueryTableViewController
self.objects is the Datasource array the PFQueryTableViewController class uses for each table row.
You have to check whether the indexPath.row is the last object inside the self.objects array.
Within MyPFQueryTableViewController.m you override the cellForRowAtIndexPath method:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object {
static NSString *CellIdentifier = #"Cell";
PFTableViewCell *cell = (PFTableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[PFTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Configure the cell
// Is this the last displaying cell?
if( indexPath.row == ([self.objects count]-1) )
{
cell.imageView.image = [UIImage imageNamed:#"End_Of_List.jpg"];
cell.textLabel.text = #"";
}
else
{
cell.textLabel.text = [object objectForKey:self.textKey];
}
return cell;
}
I have a UITableView with one section. All of the cells in that one section have cells that are derived from a subclass of UITableViewCell called PLContactCell.
What I'd like to do is, for the very last row of the table only, not use a PLContactCell. I just want to use a normal UITableViewCell that I can format however I would like. I'd also like to be able to have this cell NOT respond to being tapped.
My initial cellForRowAtIndexPath method is:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
PLContactCell *cell = [tableView dequeueReusableCellWithIdentifier:[PLContactCell reuseIdentifier]];
if (!cell) {
cell = [PLContactCell reusableCell];
cell.delegate = self;
}
id modelObject = [[sections objectAtIndex:indexPath.section] objectAtIndex:indexPath.row];
if ([modelObject isKindOfClass:[NSString class]]) {
[cell configureWithString:modelObject];
} else {
[cell configureWithUser:modelObject];
}
return cell;
}
EDIT
So I tried created a UITableView cell in the XIB file and added the reuse identifier of "newCell" to it. Then I added this code:
if (indexPath.row == [[sections objectAtIndex:indexPath.section] count] - 1) {
NSString *CellIdentifier = #"newCell";
noFormatCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
}
This doesn't do anything. My question is, how do I access the last row of the section and how do I make it so that that cell it is not a PLContactCell but a UITableView Cell.
If it's always at the end, you might consider using the footer view of the UITableView. You can then keep some extra logic out of your UITableViewDataSource.
If it HAS to be as a cell, you'd have to add an extra row count on your last section, then do an if statement check to watch out for it in your -tableView:cellForRowAtIndexPath: implementation. I would strongly urge you try the footer approach, as it's cleaner and way easier to figure out what you were doing a few months/years from now.
Here's some code. Note you'd need to make another section if you are using grouped style in the UITableView.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (section == sections.count - 1) //Looking for last section
{
return [sections objectAtIndex:section].count + 1; //Add one to the last section
}
return [sections objectAtIndex:section].count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger row = indexPath.row;
if ((sections.count == indexPath.section) && [sections objectAtIndex:indexPath.section].count == indexPath.row)
{
//Here you would create and return your UITableViewCell
}
PLContactCell *cell = [tableView dequeueReusableCellWithIdentifier:[PLContactCell reuseIdentifier]];
if (!cell) {
cell = [PLContactCell reusableCell];
cell.delegate = self;
}
id modelObject = [[sections objectAtIndex:indexPath.section] objectAtIndex:indexPath.row];
if ([modelObject isKindOfClass:[NSString class]]) {
[cell configureWithString:modelObject];
} else {
[cell configureWithUser:modelObject];
}
return cell;
}