UIButton gets created twice on cell reload - ios

Question

I have a UIButton inside a UITableViewCell. When the app is first launched, it works as expected, where I created it's frame.
When I scroll pass the cell which holds the button, it creates a second instance of the button slightly below the button.
Here's a video to illustrate my problem: http://pixori.al/DJ1k
Here's the code for the UITableViewCell and also how I populate the cells.
Not sure why it's behaving like this.
#pragma mark - UITableViewDataSource
// 3 sections, (1 = mistarOverview) (2 = hourlyForecast) (3 = dailyForecast)
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 3;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if (section == 0) {
return MAX(6,6) + 1; //TODO add getNumberOfClasses for people with 7 or 8 classes
} else if (section == 1) {
return MIN([[MAManager sharedManager].hourlyForecast count], 6) + 1;
} else {
return MIN([[MAManager sharedManager].dailyForecast count], 6) + 1;
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
// Redefine layout variables in method from `viewDidLoad`
CGFloat inset = 20; // For padding
if (! cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
}
// Sets up attributes of each cell
cell.selectionStyle = UITableViewCellSelectionStyleNone; //TODO none
cell.backgroundColor = [UIColor colorWithWhite:0 alpha:0.2];
cell.textLabel.textColor = [UIColor whiteColor];
cell.detailTextLabel.textColor = [UIColor whiteColor];
QBFlatButton* loginButton = nil;
if (indexPath.section == 0) {
if (indexPath.row == 0) {
[self configureHeaderCell:cell title:#"Grades"];
if ([cell.textLabel.text isEqual: #"Grades"] && (!loginButton) && (indexPath.row == 0) && (indexPath.section == 0)) {
UIView *cellView = cell.contentView;
CGRect loginButtonFrame = CGRectMake((cellView.frame.size.width - (80 + inset)), 18, 80, (cellView.frame.size.height));
loginButton = [[QBFlatButton alloc] initWithFrame:loginButtonFrame];
[loginButton addTarget:self action:#selector(loginButtonWasPressed)forControlEvents:UIControlEventTouchUpInside];
loginButton.faceColor = [UIColor grayColor];
loginButton.sideColor = [UIColor clearColor];
loginButton.radius = 6.0;
loginButton.margin = 4.0;
loginButton.depth = 3.0;
loginButton.alpha = 0.3;
loginButton.titleLabel.font = [UIFont fontWithName:#"HelveticaNeue-Light" size:20];
[loginButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[loginButton setTitle:#"Login" forState:UIControlStateNormal];
[cellView addSubview:loginButton];
}
} else {
cell.selectionStyle = UITableViewCellSelectionStyleBlue;
cell.textLabel.text = [NSString stringWithFormat:#"Period %ld A+", (long)indexPath.row];
cell.detailTextLabel.text = #"Class name";
//TODO get grades and config using method (TB Created)
}
} else if (indexPath.section == 1) {
if (indexPath.row == 0) {
[self configureHeaderCell:cell title:#"Hourly Forecast"];
}
else {
// Get hourly weather and configure using method
MACondition *weather = [MAManager sharedManager].hourlyForecast[indexPath.row - 1];
[self configureHourlyCell:cell weather:weather];
}
}
else if (indexPath.section == 2) {
if (indexPath.row == 0) {
[self configureHeaderCell:cell title:#"Daily Forecast"];
}
else if (indexPath.section == 2) {
// Get daily weather and configure using method
MACondition *weather = [MAManager sharedManager].dailyForecast[indexPath.row - 1];
[self configureDailyCell:cell weather:weather];
}
}
return cell;
}

Answer 1

Implement the following UITableView Delegate Method
-(void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
//In here, check the index path. When you have the cell that contains the button, pop it out from there by using [button removeFromSuperView];
}
Your problem occurs when you dequeue the cell. Since the cell is being reused, it already has the button and you're simply re-adding it again. This will solve your issue. However, I'd recommend you create a subclass for the UITableViewCell, and in it's prepareForReuse method, pop the button out. Up to you. Both will work.

Answer 2

Table view cells are not just deallocated then they move out of visible area. They are stored for reusing and then returned in tableView dequeueReusableCellWithIdentifier:CellIdentifier];
So you need to clean your cells after using or before reusing. There are several ways:
1.Add tag to your button when you create it
loginButton.tag = SOME_TAG;
just after
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
search for view with this tag
loginButton = [cell viewWithTag:SOME_TAG];
if loginButton != nil you can reuse it or remove from cell and then create a new one.
2.Implement UITableViewDelegate method
-(void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
and erase login button inside it.
3.Create custom UITableViewCellclass and implement prepareForReuse method.

Answer 3

You're adding the button every time you return a cell in this method. If you scroll the cell off the screen and back on, this method is called again for the same index path, and you will add the button again.
You declare the variable, do nothing with it, then check if it is nil. It will always be nil, so you always add the button.
A quick and dirty solution is to give the button a tag, then check for its existence using viewWithTag:.
A better solution is to make a custom cell subclass, and set one-time properties like this in the init method. Your cell contents seem very different for each section as well, so use different reuse identifiers for each section, and possibly a different cell subclass. Clearing out sub views is expensive and could hurt your scrolling performance.

Answer 4

When you run your project first time then cellForRowAtIndexPath is called.....
Then whenever you scroll tableView it again calls cellForRowAtIndexPath and reload data automatically..
So you have to take CellIdentifier as unique for each cell.
you have to remove static keyword from
static NSString *CellIdentifier = #"CellIdentifier";
now you have
NSString *CellIdentifier = #"CellIdentifier";
only this things
Now you have to write like below
NSString *CellIdentifier = [NSString stringWithFormat:#"%#",indexPath];
Now Enjoy.....