UILabel isn't added to view - ios

Question

I have two viewControllers where one of them contains a UILabel and a UIButton, and the other one a UITableView. When the UIButton in the first view is pressed the new ViewController is presented and when a row in the tableview is selected the tableview is dismissed and the UILabel in the first viewController should be updated so its text is the same as the cell name tapped in the tableview.
Code:
In the first Viewcontroller:
- (void)changeTitleWithString:(NSString *)title
{
UILabel* selected_station = [[UILabel alloc ]initWithFrame:CGRectMake(45, 153+45, 231, 20)];
[selected_station setFont:[UIFont systemFontOfSize:16.0]];
selected_station.textAlignment = NSTextAlignmentCenter;
selected_station.text = [NSString stringWithFormat:#"%#", title];
[self.view addSubview:selected_station];
NSLog(#"%#", selected_station);
NSLog(#"%#", title);
}
In second viewController
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
self.currentString = [NSString stringWithFormat:#"Cell %d", indexPath.row+1];
NewViewController *viewCOntroller = [[NewViewController alloc] init];
[viewController changeTitleWithString:self.currentString];
[self.navigationController dismissViewControllerAnimated:YES completion:nil];
}
The changeTitleWithString function is called and the string from tableview is successfully received in the function, but the UILabel won't show up. When I log out the UILabel (selected_station) it's not nil and its text is correct. Why doesn't the string show up on the view?

Answer 1

This does not look like you are referencing back to a previous allocated view controller (NewViewController). Rather you are allocating a new NewViewController.
A better approach might be to create a delegate protocol for the second view controller and make the NewViewController it's delegate --
So create a second view controller with a delegate property.
something like this
#protocol SecondViewControllerDelegate;
#interface SecondViewController : UIViewController
#property (nonatomic, strong) NSString *currentString;
#property (nonatomic, assign) id<SecondViewControllerDelegate>delegate;
#end
//----------------------------------------------------------------------------------
#protocol SecondViewControllerDelegate <NSObject>
#optional
-(void) secondViewController:(SecondViewController*)secondViewController didChangeSelectionText:(NSString *)string;
#end
Now in the implementation of the SecondViewController do something like this
#implementation SecondViewController
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
self.currentString = [NSString stringWithFormat:#"Cell %ld", indexPath.row+1];
if ([self.delegate respondsToSelector:#selector(secondViewController:didChangeSelectionText:)]) {
[self.delegate secondViewController:self didChangeSelectionText:self.currentString];
}
[self.navigationController dismissViewControllerAnimated:YES completion:nil];
}
#end
Now in the implementation of the FirstViewController (your NewViewController) do something like this
#implementation FirstViewController
-(void) showSecondController
{
SecondViewController *viewController = [[SecondViewController alloc] init];
[viewController setDelegate:self]; // set this controller as the delegate
// add the rest of the display code here
}
#pragma mark - SecondViewControllerDelegate Methods
-(void) secondViewController:(SecondViewController*)secondViewController didChangeSelectionText:(NSString *)string
{
//change your text here
}
#end
This should be enough to get you pointed in the right direction

Answer 2

In FirstViewController
- (void)changeTitleWithString:(NSString *)title :(UIView *)labelView
{
UILabel* selected_station = [[UILabel alloc ]initWithFrame:CGRectMake(45, 153+45, 231, 20)];
[selected_station setFont:[UIFont systemFontOfSize:16.0]];
selected_station.textAlignment = NSTextAlignmentCenter;
selected_station.text = title;
[labelView addSubview:selected_station];
NSLog(#"%#", selected_station);
NSLog(#"%#", title);
}
InSecondViewController
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
self.currentString = [NSString stringWithFormat:#"Cell %d", indexPath.row+1];
NewViewController *viewCOntroller = [[NewViewController alloc] init];
[viewController changeTitleWithString:self.currentString:self.view];
[self.navigationController dismissViewControllerAnimated:YES completion:nil];
}
I hope it helps