Cell and TextField not showing serialwise in UITableView - ios

Question

I am using UITextField, and every row have a CellLable and TextField. Lable and TextField data comes from array. While running the app, all data are comes fine but when scrolling the Tableview, Last 2-3 Rows unorganized.
NSMutableArray
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
ArrFieldData= [NSMutableArray arrayWithObjects:#"Fist Name", #"Last Name",#"User Name", #"Password",#"Confirm Password", #"Gender",#"DOB", #"Profile Pic",#"Deparment", #"Joining Date",#"Education", #"Role", nil];
Now cellForRowAtIndexPath Function
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
UITextField *txtField ;
if (cell ==nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
txtField = [[UITextField alloc]initWithFrame:CGRectMake([UIScreen mainScreen].bounds.size.width/3 + 40, 2, [UIScreen mainScreen].bounds.size.width/2, cell.layer.frame.size.height -5)];
[self setUpCell:cell withIndexPath:indexPath withTextField:txtField];
}
[self UpdateCell:cell withIndexPath:indexPath withTextField:txtField];
return cell;
}
SetUp Cell Function
-(void)setUpCell:(UITableViewCell *)cell withIndexPath:(NSIndexPath *)indexPath withTextField: (UITextField *)txtField {
cell.textLabel.text = [ArrFieldData objectAtIndex:indexPath.row];
cell.textLabel.font = [UIFont systemFontOfSize:12.0];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
txtField.tag = indexPath.row+1;
txtField.layer.borderColor = [UIColor grayColor].CGColor;
txtField.delegate = self;
txtField.layer.borderWidth = 1.0f;
txtField.layer.cornerRadius = 4.0f;
txtField.placeholder = cell.textLabel.text;
txtField.font = [UIFont systemFontOfSize:12.0];
[cell.contentView addSubview: txtField];
}
Update Cell Function
-(void)UpdateCell:(UITableViewCell *)cell withIndexPath:(NSIndexPath *)indexPath withTextField: (UITextField *)txtField {
[self setUpCell:cell withIndexPath:indexPath withTextField:txtField];
}
First time Running the application, It is showing all cell and textfield data are Serialize. but when scroll some cell and TextField are not serialize as per Array Value. I am attaching the Simulator Screenshot.
First Screenshot for First time running, and second for when i scroll the Tableview. See the last 4-5 cell and Textfield Placeholder text. They are un-organized. I want it shouldn't change.

Answer 1

As you are using reusable cells, like
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
UITextField *txtField ;
if (cell ==nil)
{
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
txtField = [[UITextField alloc]initWithFrame:CGRectMake([UIScreen mainScreen].bounds.size.width/3 + 40, 2, [UIScreen mainScreen].bounds.size.width/2, cell.layer.frame.size.height -5)];
[self setUpCell:cell withIndexPath:indexPath withTextField:txtField];
}
[self UpdateCell:cell withIndexPath:indexPath withTextField:txtField];
return cell;
}
UITableView uses the concept of reusable cell to achieve maximum performance by reducing the memory consumption, and to exploit this feature of reusing cells you can use the above UITableView's API's to achieve that.
But before using any feature it's very important to understand the working and the usage of any feature.
In your above implementation of tableView: cellForRowAtIndexPath: method, you have used the concept of cell reusability.
If the cells doesn't exist and are created for the first time, than they are allocated(every subview is created and added on the content view of the cell), customized and initialized with the data from the data source of the respective index path.
But in case the cells are reused(as they were already created for any other index path), there subviews exist with the data already filled for the previous index path for which it was created.
Now there are two things we can do to use already created cell for the current index path,
1) if the cells contain subview with data then remove the subviews and recreate the new ones, customize and populate them with the data.
2) rather than releasing the previous subviews and creating new ones, refill the data for the data model of the corresponding index path.
In your case, if the cell is being created for any index path, than the text filed for it is also created and if it's reused than the new text field is not created and it's being reused from the previously created cell thus the issue of the placeholder text not matching with the left text.
So, in order to solve your problem I think you should either create the textfield when the cell is created and if the cells are reused than refill the data in the text filed from the data source of the corresponding index path.

Answer 2

Your problem is due to a feature of UITableView. When you scroll a UITableView the indexPath is updated so you are not getting the index values you are expecting from the tableView.
Instead of adding a UITextField programmatically. Create a Custom UITableViewCell and from the method cellForRowAtIndexPath: update the placeHolder of your UITextField. The tableView will take care of scrolling for you.
Use this code :
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
UITextField *txtField ;
if (cell ==nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
cell.textField.placeholder= cell.textLabel.text;
}
cell.textField.placeholder= cell.textLabel.text;
return cell;
}