Losing UIButton within a custom cell when reloading table - ios

I've custom UITableViewCells where I placed buttons dynamically in code. I have programmatically set actions for such buttons, and when the action is triggered, then I need to reload the table, among other things. Once reload is called, the sender button disappears, and I don't know why... Could somebody give me a hint for the possible reason? If button is not tapped, and I scroll up and down through the table, it remains there.
Thanks!
EDIT
This is a code snippet from cellForRowAtIndexPath:
- (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSArray *listData =[self.tableViewEntries objectForKey:[self.sortedKeys objectAtIndex:[indexPath section]]];
UITableViewCell *cell;
if (indexPath.section == 0) {
switch (indexPath.row) {
case 0: {
cell = [self.tableView dequeueReusableCellWithIdentifier:#"firstCell"];
((CustomCell *)cell).cellTextField.tag = firstCellTag;
cell.tag = firstCellTag;
break;
}
case 1: {
cell = [self.tableView dequeueReusableCellWithIdentifier:#"secondCell"];
((CustomCell *)cell).cellTextField.tag = secondCellTag;
cell.tag = secondCellTag;
break;
}
}
return cell;
}
The CustomCell I've defined is loaded from a nib. Those cells have a UITextField for user input and a UIView where I set or remove the buttons dynamically in code according to the user input within the text field. The buttons are created in code, and their actions are set in code as well:
- (void)setButtonForCell:(UITableViewCell *)cell withResult:(BOOL)isValid
{
UIImage* validationButtonNormalImage = nil;
UIImage* validationButtonHighlightImage = nil;
UIButton *validationButton = [UIButton buttonWithType:UIButtonTypeCustom];
[validationButton setFrame:CGRectMake(0, 0, ((CustomCell *)cell).cellValidationView.frame.size.width, ((CustomCell *)cell).cellValidationView.frame.size.height)];
if (isValid) {
validationButtonNormalImage =[[UIImage imageNamed:#"success.png"] stretchableImageWithLeftCapWidth:5.0 topCapHeight:0.0];
validationButtonHighlightImage =[[UIImage imageNamed:#"success.png"] stretchableImageWithLeftCapWidth:5.0 topCapHeight:0.0];
[validationButton removeTarget:self
action:#selector(validationButtonTapped:)
forControlEvents:UIControlEventTouchUpInside];
}
else {
validationButtonNormalImage =[[UIImage imageNamed:#"error.png"] stretchableImageWithLeftCapWidth:5.0 topCapHeight:0.0];
validationButtonHighlightImage =[[UIImage imageNamed:#"error.png"] stretchableImageWithLeftCapWidth:5.0 topCapHeight:0.0];
[validationButton setTag:cell.tag];
[validationButton removeTarget:self
action:#selector(validationButtonTapped:)
forControlEvents:UIControlEventTouchUpInside];
[validationButton addTarget:self
action:#selector(validationButtonTapped:)
forControlEvents:UIControlEventTouchUpInside];
}
[validationButton setBackgroundImage:validationButtonNormalImage forState:UIControlStateNormal];
[validationButton setBackgroundImage:validationButtonHighlightImage forState:UIControlStateHighlighted];
[((CustomCell *)cell).cellValidationView.subviews makeObjectsPerformSelector: #selector(removeFromSuperview)];
[((CustomCell *)cell).cellValidationView addSubview:validationButton];
}
Then, in validationButtonTapped:, I do some tasks and call to [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:NO];, and there is when I loose the button from the view. However, if I don`t tap the button and I scroll down and up again to get 'cellForRowAtIndexPath:' called again, the button remains here. It is like I only loose it when calling for a reload.
Any help?

Cells are usually reused if you are following the usual cellForRowAtIndexPath: pattern. Do you remove all subviews in prepareForReuse for each cell? If you didn't then you would see unexpected buttons on cells as you scroll up and down. You probably need to add the buttons as required in each cell's configuration after you get the cell for reuse (or in newer code, dequeue a cell) in cellForRowAtIndexPath:.

Related

Messing UIButton in each UICollectionViewCell in Scrolling Filmstrip

This is a follow-up question to my previous one and this time I have a problem with UIButton that I have added in each UICollectionViewCell. Before diving into the problem, let me brief out all I've got so far.
Here's the basic rundown of how my UICollectionView in Scrolling Filmstrip style within UITableView works:
Create a normal UITableView with a custom UITableViewCell
Create a custom UIView that will be added to the cell's contentView
The custom UIView will contain a UICollectionView
The custom UIView will be the datasource and delegate for the
UICollectionView and manage the flow layout of the UICollectionView
Use a custom UICollectionViewCell to handle the collection view data
Use NSNotification to notify the master controller's UITableView when
a collection view cell has been selected and load the detail view.
So far, I've been able to add UIButton in each UICollectionViewCell and when I tap the UIButton its image will change to checked mark but the problem occurs when I scroll up/down. Once the cell with checked mark UIButton is off-screen and scrolled back on-screen again, UIButton image starts to get messed around. For example, when UIButton image in cell1 should be checked mark but it's not. Instead checked mark will be appeared in another cell.
Here below is my relevant code:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
PostsCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"PostsCollectionViewCell" forIndexPath:indexPath];
NSDictionary *cellData = [self.collectionData objectAtIndex:[indexPath row]];
cell.postTextLabel.text = [cellData objectForKey:#"text"];
cell.locationNameLabel.text = [cellData objectForKey:#"locationName"];
// >>> Select Button <<<
UIButton *selectButton = [UIButton buttonWithType:UIButtonTypeCustom];
[selectButton setFrame:CGRectMake(110, 150, 20, 20)];
[selectButton setImage:[UIImage imageNamed:#"uncheckedDot.png"] forState:UIControlStateNormal];
[selectButton setImage:[UIImage imageNamed:#"checkedDot.png"] forState:UIControlStateSelected];
[cell.contentView addSubview:selectButton];
[selectButton addTarget:self
action:#selector(buttonPressed:)
forControlEvents:UIControlEventTouchUpInside];
// >>> End Select Button <<<<
return cell;
}
// >>> Select Button Method <<<
-(void) buttonPressed:(UIButton *)sender
{
if([sender isSelected]){
//...
[sender setSelected:NO];
} else {
//...
[sender setSelected:YES];
}
}
Any help would be greatly appreciated! Thanks in advance.
Man, you should be aware that cells (both for UITableView and UICollectionView) are reused via the reuse deque under the hood of UIKit and are not obligated to keep their state consistent with regard to their position in a table view or a collection view. What you need to do is to make sure that the return value of dequeueReusableCellWithReuseIdentifier: is then properly initialized (or, in your case, re-initialized) in accordance with the state of your data model. Basically, you need to store the state of your "checkmarks" (or "checkboxes", what have you) in an array or any other data structure. Then, when you call dequeueReusableCellWithReuseIdentifier:, you should apply that stored state to the return value (the cell you're going to return for the collection view) you just got. Hope it's explained good enough. Good luck.
Maintain in your Data source which cell is to be selected by adding a key for each data source dict. For example:#"isSelected"
Then in cellForRowAtIndexPath:
if ([[cellData valueForKey:#"isSelected"] boolValue]) {
[selectButton setSelected:NO];
} else {
[selectButton setSelected:YES];
}
and in your -(void) buttonPressed:(UIButton *)sender Method:
CGPoint point = [self.collectionView convertPoint:CGPointZero fromView:sender];
NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:point];
NSDictionary *cellData = [self.collectionData objectAtIndex:[indexPath row]];
if ([[cellData valueForKey:#"isSelected"] boolValue]) {
[cellData setValue:#"false" forKey:#"isSelected"];
} else {
[cellData setValue:#"true" forKey:#"isSelected"];
}
[self.framesCollectionView reloadItemsAtIndexPaths:#[indexPath]];
AND
In your cellForRowAtIndexPath set a tag for the UIButton. Then before adding a UIButton as subview to the cell's contentView check if a view with this tag already exists. In case the cell has been reused, just use the already existing button.

Strange behavior when adding UIButton to UICollectionViewCell

I'm trying to add aUIButton to aUICollectionViewCell. The main purpose of the button is to let users to select their favourites.
When they click on theUIButton, the UIButton will display a glowing star image, showing that the item has been picked as favourite.
Click on the UIButton again, and the button return to display the original image with an empty star, meaning deselection.
The way I realize this is as below:
1 - In the storyboard, put an UIButton into theUICollectionViewCell, ctrl-drag the button to the cell's .h file to setup an action called
-(IBAction)favoriteBtnClick:(id)sender;
2 - In the cell's .m file, edit the action as follows:
-(IBAction)favoriteBtnClick:(id)sender {
if ([self.favoriteChecked isEqualToString:#"NO"]) {
UIImage *image = [UIImage imageNamed:#"FavoriteSelected.PNG"];
[sender setBackgroundImage:image forState:UIControlStateNormal];
self.favoriteChecked = #"YES";
} else if ([self.favoriteChecked isEqualToString:#"YES"]) {
UIImage *image = [UIImage imageNamed:#"FavoriteBlank.PNG"];
[sender setBackgroundImage:image forState:UIControlStateNormal];
}
}
However, when I try to run the UICollectionView, when I clicked the button on one cell, "strange" behaviors occurred:
1 - Click on one cell to turn one button to favorite glowing star, buttons on some other cells below also turn selected, after your scroll down the list.
2 - The switching only functions for one cycle. After you finish the first round of select and deselect, there is no longer reactions upon further clicking.
Can anybody help me understand the reasons for this and probably give me some hints on how to solve it?
Thank you!
Regards,
Paul
Add this code in your button action
CGPoint ButtonPoint = [sender convertPoint:CGPointZero toView:self.collectionView];
NSIndexPath *ButtonIndex = [self.collectionView indexPathForItemAtPoint:ButtonPoint];
buttonindexpath = ButtonIndex.row
[collectionView reloadData];
Now in your cellForItemAtIndexPath, check if indexPath.row == buttonindexpath, if yes give the code you gave in button action....
ie....
if (indexPath.row == buttonindexpath)
{
if ([self.favoriteChecked isEqualToString:#"NO"])
{
UIImage *image = [UIImage imageNamed:#"FavoriteSelected.PNG"];
[sender setBackgroundImage:image forState:UIControlStateNormal];
self.favoriteChecked = #"YES";
}
else if ([self.favoriteChecked isEqualToString:#"YES"])
{
UIImage *image = [UIImage imageNamed:#"FavoriteBlank.PNG"];
[sender setBackgroundImage:image forState:UIControlStateNormal];
}
}
Hope this works fine
This is happening because of cell reuse. since self.favoriteChecked is a property inside the custom collection cell class, and its value is updated only inside that class causes this issue.
Solution to this problem is, if you are using custom object model to populate collection cells from viewcontroller, then on favourite button click update the favourite status on that custom object and in cellForItemAtIndexPath method check the value of favourite status and update the favoriteChecked status of custom collectionviewcell class.
If you are not using custom object, you need to keep a list of favourite items separately either indexpaths of favourite item or unique identifier of fav item. Then in cellForItemAtIndexPath method check the value of favourite status and update the favoriteChecked status of custom collectionviewcell class.
This is no no a strange behaviour. You have load the cells from the model data objects. You have to track & keep the state change of button clicked data in an array & then load the cell data values.
Here is a sample code : which aligns with solution to your problem.
NSMutableArray *favoriteStatusArray = [[NSMutableArray alloc]init];
// assume favoriteStatusArray is initialized with all BOOL as NO.
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
SomeCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
cell.favoriteButton.tag = indexPath.row;
[cell.favoriteButton addTarget:self action:#selector(peformFavoriteChange:) forControlEvents:UIControlEventTouchUpInside];
if([[favoriteStatusArray objectAtIndex:indexPath.row] boolValue] == NO)
UIImage *image = [UIImage imageNamed:#"FavoriteSelected.PNG"];
[cell.favoriteButton setBackgroundImage:image forState:UIControlStateNormal];
}else {
UIImage *image = [UIImage imageNamed:#"FavoriteBlank.PNG"];
[cell.favoriteButton setBackgroundImage:image forState:UIControlStateNormal];
}
return cell;
}
-(void)peformFavoriteChange:(UIButton *)sender
{
BOOL oldValue = [[favoriteStatusArray objectAtIndex:sender.tag] boolValue];
[favoriteStatusArray replaceObjectAtIndex:sender.tag withObject:[NSNumber numberWithBool:!oldValue]];
[myCollectionView reloadData];
}
Hope you got the idea of doing this.

Maintain state of custom button in UITableview cell when scrolls

I know this question is very similar to other questions, but i doesn't resolve the problem using that approach.i follow most of the available solution but it doesn't work for me..
I know that when tableview scrolls it reuse cell but i doesn't know the approach of maintaining the button state . i'll try with following link
How to use Reusable Cells in uitableview for IOS
IOS: Maintaining button state in uitableviewcell
How to Handle Favourite button clicks in custom Tableview cells iOS?
I done all the things.use tags, use touch points and all but nothing seems to work for me.so help me out..and here is my sample code
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
cell = (subcategoryCell *)[tableView dequeueReusableCellWithIdentifier:NSStringFromClass([subcategoryCell class]) forIndexPath:indexPath];
/*
* Set button for cell to subscribe with it
*/
cell.btnsubscribe = (UIButton *)[cell.contentView viewWithTag:303];
cell.btnsubscribe.tag = indexPath.row ;
[cell.btnsubscribe addTarget:self action:#selector(clickBtnSubscribe:) forControlEvents:UIControlEventTouchUpInside];
if (![_arraybtnState containsObject:listid] )
{
[cell.btnsubscribe setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
[cell.btnsubscribe setSelected:YES];
}
else {
[cell.btnsubscribe setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
[cell.btnsubscribe setSelected:NO];
}
return cell;
}
_arrbtnstate contains the ids that user follows.
and listid contains unique id comes from database too
And the click event method...
- (IBAction)clickBtnSubscribe:(id)sender {
UIButton *button = (UIButton*)sender;
NSLog(#"selected button tag %li", (long)button.tag);
NSNumber *tagnum = [NSNumber numberWithLong:(long)button.tag];
if (button.selected) {
[self.arraybtnState addObject:tagnum];
[button setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
NSLog(#"Subscribe");
[self subscribeButton:button.tag];
[button setSelected:NO];
}
else
{
[self.arraybtnState removeObject:tagnum];
[button setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
NSLog(#"unsubscribe");
[self unsubscribeButton:button.tag];
[button setSelected:YES];
}
}
Note: In this code, button is created in storyboard.,but i'll also tried without storyboard too.
First of all this line cell.btnsubscribe = (UIButton *)[cell.contentView viewWithTag:303]; is to be changed. Follow the below steps and try
in custom subcategoryCell connect IBOutlet to btnsubscribe.
in storyboard, you can set both selected and not normal images to a UIButton, here it is btnsubscribe. If you find it difficult follow this
in cellForRowAtIndexPath: remove below lines
[cell.btnsubscribe setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
[cell.btnsubscribe setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
cell.btnsubscribe = (UIButton *)[cell.contentView viewWithTag:303];
update the following lines
if (![_arraybtnState containsObject:listid] )
{
[cell.btnsubscribe setSelected:YES];
}
else {
[cell.btnsubscribe setSelected:NO];
}
or simply [cell.btnsubscribe setSelected:(![_arraybtnState containsObject:listid] )];
Keep the addTarget in cell for row method (since you have custom cell class, it is better to move the button action to cell class and pass the result to viewcontroller by callback or delegate. not discussing that now but recomments) and update the clickBtnSubscribe: by removing
[button setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
[button setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
these lines. assumes other parts are working properly.
You are setting Selected and unselected image for button's Normal state in both cases i.e UIControlStateNormal.
When you are using selected method you do not require to setImage again. Just set Image for Normal and selected state for button properly in cellForRowAtIndexpath or in xib. You are done.
First remove the setting image in clickBtnSubscribe:() method.
Now in your storyboard set images for Normal and selected state.
Also remove set Image in cell for row at indexpath as you have already done in view.
You can maintain the state of the buttons as-
// initialize your array only once
_arraybtnState = [[NSMutableArray alloc] init];
// cell for row at index path would be
//initially each cell will have follow image
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
cell = (subcategoryCell *)[tableView dequeueReusableCellWithIdentifier:NSStringFromClass([subcategoryCell class]) forIndexPath:indexPath];
[cell.btnsubscribe setTag: indexPath.row];
[cell.btnsubscribe addTarget:self action:#selector(clickBtnSubscribe:) forControlEvents:UIControlEventTouchUpInside];
if (![_arraybtnState containsObject:[NSNumber numberWithInt:indexPath.row]] )
{
[cell.btnsubscribe setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
[cell.btnsubscribe setSelected:YES];
}
else
{
[cell.btnsubscribe setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
[cell.btnsubscribe setSelected:NO];
}
return cell;
}
- (IBAction)clickBtnSubscribe:(id)sender {
UIButton *button = (UIButton*)sender;
NSLog(#"selected button tag %li", (long)button.tag);
NSNumber *tagnum = [NSNumber numberWithLong:(long)button.tag];
if (button.selected) {
[self.arraybtnState addObject:tagnum];
NSLog(#"Subscribe");
[self subscribeButton:button.tag];
[button setSelected:NO];
}
else
{
[self.arraybtnState removeObject:tagnum];
NSLog(#"unsubscribe");
[self unsubscribeButton:button.tag];
[button setSelected:YES];
}
//after doing modification update the respective row as
UIButton *button = (UIButton *)sender;
// Find Point in Superview
CGPoint pointInSuperview = [button.superview convertPoint:button.center toView:self.tableView];
// Infer Index Path
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:pointInSuperview];
//relaod the row
NSArray* indexPathModel = [NSArray arrayWithObjects:indexPath, nil];
[self.tableView reloadRowsAtIndexPaths: indexPathModel withRowAnimation:UITableViewRowAnimationNone];
}
reloading row will reflect the changes done in the modal to the UI.
I think you can put this line in viewDidLoad or after you load what all have subscribed .
_arraybtnState = [NSMutableArray arrayWithArray:[self.strSubscribe componentsSeparatedByString:#","]];
Then the cellForRowAtIndexPath will loook like below
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
cell = (subcategoryCell *)[tableView dequeueReusableCellWithIdentifier:NSStringFromClass([subcategoryCell class]) forIndexPath:indexPath];
/*
* Set button for cell to subscribe with it
*/
cell.btnsubscribe = (UIButton *)[cell.contentView viewWithTag:303];
cell.btnsubscribe.tag = indexPath.row ;
[cell.btnsubscribe addTarget:self action:#selector(clickBtnSubscribe:) forControlEvents:UIControlEventTouchUpInside];
if (![_arraybtnState containsObject:[NSNumber numberWithInt:indexPath.row]] ) {
[cell.btnsubscribe setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
}
else {
[cell.btnsubscribe setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
}
return cell;
}
and then the btn click method as
- (IBAction)clickBtnSubscribe:(id)sender {
UIButton *button = (UIButton*)sender;
NSLog(#"selected button tag %li", (long)button.tag);
NSNumber *tagnum = [NSNumber numberWithLong:(long)button.tag];
if (![_arraybtnState containsObject:tagnum] )
{
[_arraybtnState addObject:tagnum];
[button setImage:[UIImage imageNamed:#"following"] forState:UIControlStateNormal];
NSLog(#"Subscribe");
[self subscribeButton:button.tag];
}
else {
[self.arraybtnState removeObject:tagnum];
[button setImage:[UIImage imageNamed:#"follow"] forState:UIControlStateNormal];
NSLog(#"unsubscribe");
[self unsubscribeButton:button.tag];
}
}
Two easy solutions and quite fast to implement :
Keep track of the state in an array/dictionary
You can store your states in an array of states, i'll make an example.
(Note: i'm coding this without compiling, I might mispel some stuff, feel free to edit my post)
in your viewDidLoad
arrState = [[NSMutableArray alloc]init];
for (yourObject *object in dataArray){
//For every object that you use to load your tableview, this can be strings or anything really
[arrState addObject:#NO];
}
In your cellForRow
...
//This will either put YES or NO depending on the element in the state array.
[cell.button setSelected:[arrState objectAtIndex:indexPath.row]];
...
Boom, done.
You can also keep track of this in a database or anything persistent, and then you'd simply load whatever your field contains for a selected record. This is more relevant if we're talking about, for example, something like favourites or something that will be there until the user decides otherwise. If it's just to keep track of your button states during the lifetime of your view, then ignore this part of the answer.
If you need to keep it alive forever (even when the app closes), then you'd most probably need a database :)

Some rows never have UIButtons when UITableView is created

I have a UITableView that is never consistent. This table view has 2 sections.
I have created 2 UIButtons, they both are practically the same image, but one is grey and one is red.
Every row in the UITableView is supposed to have the grey button when the UITableView first loads, and then if a user taps a button then it switches to the red version of the button.
For some reason, about 80% of the time when I load the view controller with this UITableView on my iPhone, the first 2 rows in the first section will not have a button. What's weird is if I tap my finger where the button is supposed to be 2 things happen:
The functionality attached to the button works and NSLogs in the console in xcode.
The red button appears.
So it's like the grey button is there, it's just invisible. This doesn't work because if a user sees 2 rows without a button they are going to think something is broken or that they can't tap on that row.
Also, if I scroll to the very bottom of my UITableView, and then scroll back up again, the invisible grey buttons will magically appear like they were there the whole time.
Here are the first 3 method implementations that are involved in creating my UITableView:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 2 ;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if(section == 0)
return [self.potentiaFriendsInParseFirstNamesArray count];
if(section == 1)
return [self.potentiaFriendsNotInParseFirstNamesArray count];
else return 0;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
if(section == 0)
return #"Friends Using The App";
if(section == 1)
return #"Send to Contact";
else return #"nil";
}
And then here is my cellForRowAtIndexPath method implementation which does most of the work in creating the UITableView and which actually creates the UIButton settings for each row. The if else statement really has 2 sets of nearly identical code, the only difference is one is for section 1 of the table view and the other is for section 2:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"SettingsCell";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (indexPath.section == 0) {
NSString *firstNameForTableView = [self.potentiaFriendsInParseFirstNamesArray objectAtIndex:indexPath.row];
PFUser *user = [self.allUsersInParse objectAtIndex:indexPath.row];
UIImage *addUserButtonImage = [UIImage imageNamed:#"SliderThumb-Normal-g"];
UIImage *addUserButtonImageHighlighted = [UIImage imageNamed:#"SliderThumb-Normal"];
UIButton *addUserButton = [[UIButton alloc]init];
addUserButton.frame = CGRectMake(237, -10, 64, 64);
[addUserButton setImage:addUserButtonImage forState:UIControlStateNormal];
[addUserButton setImage:addUserButtonImageHighlighted forState:UIControlStateHighlighted];
[addUserButton setImage:addUserButtonImageHighlighted forState:UIControlStateSelected];
[addUserButton addTarget:self action:#selector(handleTouchUpInside:) forControlEvents:UIControlEventTouchUpInside];
addUserButton.tag = indexPath.row;
[cell.textLabel setText:firstNameForTableView];
[cell.detailTextLabel setText:user.username];
[cell.contentView addSubview:addUserButton];
} else {
NSString *firstNameForTableView2 = [self.potentiaFriendsNotInParseFirstNamesArray objectAtIndex:indexPath.row];
NSString *userNameForTableView2 = [self.potentiaFriendsPhoneNumberArray objectAtIndex:indexPath.row];
UIImage *addFriendButtonImage = [UIImage imageNamed:#"SliderThumb-Normal-G"];
UIImage *addFriendButtonImageHighlighted = [UIImage imageNamed:#"SliderThumb-Normal"];
UIButton *addFriendButton = [[UIButton alloc]init];
addFriendButton.frame = CGRectMake(237, -10, 64, 64);
[addFriendButton setImage:addFriendButtonImage forState:UIControlStateNormal];
[addFriendButton setImage:addFriendButtonImageHighlighted forState:UIControlStateHighlighted];
[addFriendButton setImage:addFriendButtonImageHighlighted forState:UIControlStateSelected];
[addFriendButton addTarget:self action:#selector(handleTouchUpInsideForNonUsers:) forControlEvents:UIControlEventTouchUpInside];
addFriendButton.tag = indexPath.row;
[cell.textLabel setText:firstNameForTableView2];
[cell.detailTextLabel setText:userNameForTableView2];
[cell.contentView addSubview:addFriendButton];
}
return cell;
}
I have not included the full method implementations that these 2 statements trigger because they only handle the functionality attached to each button, and most likely have nothing to do with this issue, but I will post them here anyways. These 2 statements can be found in the if else for cellForRowAtIndexPath and handle the touch events for the 2 sections of the table view:
[addFriendButton addTarget:self action:#selector(handleTouchUpInsideForNonUsers:) forControlEvents:UIControlEventTouchUpInside];
[addFriendButton addTarget:self action:#selector(handleTouchUpInside:) forControlEvents:UIControlEventTouchUpInside];
I see the pattern of trying to set up a custom UITableViewCell from within tableView:cellForRowAtIndexPath: quite a lot. The trouble is that I believe it to be the wrong place to do it. If you're really only using a built-in UITableViewCell, then it's the right place; for custom cells, it's not.
I'd recommend making a UITableViewCell subclass with a "setup" method that takes an object and uses that object to set up the cell's UI.
For instance, take section 0 from your UITableView. I'd do something like this:
#interface UserTableViewCell : UITableViewCell
// properties to IBOutlet connections for UI setup
- (void)setupWithUser:(PFUser *)user;
#end
#implementation UserTableViewCell
- (void)setupWithUser:(PFUser *)user {
// Set up your UI with properties from 'user'
}
- (IBAction)buttonPressed:(UIButton *)sender {
// Respond to the button press
}
This way, you can set up the cell's layout as well as images for the button in IB, rather than code. This also makes the code a lot easier to read (and re-read 6 months later!).
Also, unless the 2 cells (section 0 and section 1) are really interchangeable, I'd recommend two different subclasses of UITableViewCell to give you greater control, rather than trying to force one to act like the other or vice versa. Then, you simply assign different identifiers and recycle the appropriate type.

IOS: Maintaining button state in uitableviewcell

I have an iPhone app problem that's been bugging me for a few days and it really doesn't seem like it should be this difficult so I'm sure I'm missing something obvious. I have researched plenty of forum discussions on "similar" topics but nothing that actually addresses this issue, specifically.
To be clear, if there is some piece of documentation or some other source that I should research, please point me in the right direction.
Here goes...
I have a list of items that I display to the user within a table (uitableview). The cell (uitableviewcell) for each item is custom and contains an image and a Like button (uibutton). As expected, for each item in the the table, the user can click the Like button or ignore it. The like button calls a separate process to update the server. Simple, right?
So, here is the issue:
When the Like button is clicked on a particular cell, the Selected state works fine but the moment you scroll the cell out of view, other random cells in the table show the Like button as Selected even though they were never touched. Because the cells are reused, for obvious performance reasons, I understand why this could happen. What I don't understand is why my approach (see code below) would not override or reset the button's state the way I think it should. For brevity, I am only including the relevant code here (hopefully formatted properly):
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"MyCustomCell";
MyCustomViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[MyCustomViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
}
NSString *myRating = [[self.dataArray objectAtIndex:indexPath.row] valueForKey:#"my_rating"];
// Create the Like button
UIButton *likeButton = [[UIButton alloc] initWithFrame:CGRectMake(260, 68, 40, 40)];
[likeButton setImage:[UIImage imageNamed:#"thumbsUp"] forState:UIControlStateNormal];
[likeButton setImage:[UIImage imageNamed:#"thumbsUpSelected"] forState:UIControlStateSelected];
if (myRating == #"9") {
[likeButton setSelected:YES];
}
[likeButton setTitle:#"9" forState:UIControlStateNormal];
[likeButton setTag:indexPath.row];
[cell.contentView addSubview:likeButton];
[likeButton addTarget:self action:#selector(likeButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
return cell;
}
- (void)likeButtonPressed:(UIButton *)sender {
// Changed the Selected state on the button
UIButton *button = (UIButton *)sender;
button.selected = !button.selected;
// Create a new object with the user's rating and then replace it in the dataArray
NSString *ratingText = sender.titleLabel.text;
NSMutableArray *myMutableArray = [[self.dataArray objectAtIndex:row] mutableCopy];
[myMutableArray setValue:ratingText forKey:#"my_rating"];
[self.dataArray replaceObjectAtIndex:row withObject:myMutableArray];
}
So, I've been through many iterations of this but I can't seem to get the state of the button to show the Selected image for those items that are Liked and keep the normal image for those items that have not been Liked.
Any help or advice would be greatly appreciated.
there is a simple way out of this. you can trick the button to keep being in the latest selected state.
make a mutable array, for the purpose of keeping the selected state of the button
selectedButton = [[NSMutableArray alloc]init];//i've already defined the array at the .h file
for (int i = 0; i<yourTableSize; i++) //yourTableSize = how many rows u got
{
[selectedButton addObject:#"NO"];
}
at the tableviewcell method, declare your button and set it so that it refers to the mutablearray to set it's selected state
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil)
{
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:nil];
}
UIImage *img = [UIImage imageNamed:#"btn_unselected.png"];
UIButton *toggleButton = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, img.size.width, img.size.height)];
[toggleButton setImage:img forState:UIControlStateNormal];
img = [UIImage imageNamed:#"btn_selected.png"];
[toggleButton setImage:img forState:UIControlStateSelected];
[toggleButton setTag:indexPath.row+100];//set the tag whichever way you wanted it, i set it this way so that the button will have tags that is corresponding with the table's indexpath.row
[toggleButton addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:toggleButton];
//and now we set the button's selected state, everytime the table reuse/redraw the cell the button will set it's selected state according to the array
if([[selectedButton objectAtIndex:indexPath.row]isEqualToString:#"NO"])
{
[toggleButton setSelected:NO];
}
else
{
[toggleButton setSelected:YES];
}
return cell;
and finally, create the method which the button triggered when the button is pressed, to change it's selected state
-(void)buttonPressed:(UIButton*)sender
{
int x = sender.tag - 100; //get the table's row
if([sender isSelected]) //if the button is selected, deselect it, and then replace the "YES" in the array with "NO"
{
[selectedButton replaceObjectAtIndex:x withObject:#"NO"];
[sender setSelected:NO];
}
else if (![sender isSelected]) //if the button is unselected, select it, and then replace the "NO" in the array with "YES"
{
[selectedButton replaceObjectAtIndex:x withObject:#"YES"];
[sender setSelected:YES];
}
}
The problem is that every time you create or reuse a cell you're giving it a new like button, so when you reuse a cell where the like button has been activated, you're giving it a deactivated like button but the old, activated like button is still there as well.
Instead of creating a like button every time you need a cell, you should just be setting the state of an existing like button. See the answers to this question for some possible ways of handling that.
This is not valid (At least not if you are trying to compare strings my contents instead of addresses):
if (myRating == #"9")
Try this:
if ([myRating isEqualToString:#"9"])
And +1 to yuji for noticing the multiple button creation.

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