Adding a UILabel Programmatically with the Current Time - iphone

Question

I have an issue. Maybe I've got something in the wrong place or something, but dang I just can't figure it out! Any help would be appreciated.
I am trying to simply make a clock programmatically that shows only in my subview.
I've setup a timer along with an updater -(void) that I want to show in my subView that I create. I am building the subview programmatically which is the reason for not adding an IBOutlet and just connecting it in my storyboard - I'm trying do do it all with just code.
I am getting the error on my updateTimer label that says - Use of undeclared identifier 'rightLabel' and it's just not working out for me. HA HA - any help would be GREATLY appreciated!
.h
#interface DemoRootViewController : UIViewController <PaperFoldViewDelegate> {
NSTimer *timer;
}
#property (nonatomic, strong) UIView *rightView;
-(void)updateTimer;
.m
- (id)init
{
self = [super init];
if (self) {
//Timer Setup
timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(updateTimer) userInfo:nil repeats:YES];
//PaperFold Setup
_paperFoldView = [[PaperFoldView alloc] initWithFrame:CGRectMake(0,0,[self.view bounds].size.width,[self.view bounds].size.height)];
[_paperFoldView setAutoresizingMask:UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth];
[self.view addSubview:_paperFoldView];
//Setup Subview
_rightView = [[UIView alloc] initWithFrame:CGRectMake(0,0,240,[self.view bounds].size.height)];
//Setup UILabel
UILabel *rightLabel = [[UILabel alloc] initWithFrame:_rightView.frame];
[_rightView addSubview:rightLabel];
//Using PaperFold Framework to Add the Subview (this works fine)
[_paperFoldView setRightFoldContentView:_rightView foldCount:2 pullFactor:1];
}
return self;
}
-(void)updateTimer {
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"hh:mm:ss"];
//This is where I get my error "Use of Undeclared Identifier 'rightLabel'
rightLabel.text = [formatter stringFromDate:[NSDate date]];
}
#end

Answer 1

You don't have rightLabel declared as a property (or instance variable). Just change your .m to the code below:
.m
#interface DemoRootViewController ()
#property (nonatomic, strong) UILabel *rightLabel;
#property (nonatomic, strong) NSDateFormatter *dateFormatter;
#end
#implementation DemoRootViewController
- (id)init
{
self = [super init];
if (self) {
//Timer Setup
timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(updateTimer) userInfo:nil repeats:YES];
//PaperFold Setup
_paperFoldView = [[PaperFoldView alloc] initWithFrame:CGRectMake(0,0,[self.view bounds].size.width,[self.view bounds].size.height)];
[_paperFoldView setAutoresizingMask:UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth];
[self.view addSubview:_paperFoldView];
//Setup Subview
_rightView = [[UIView alloc] initWithFrame:CGRectMake(0,0,240,[self.view bounds].size.height)];
//Setup UILabel
self.rightLabel = [[UILabel alloc] initWithFrame:_rightView.frame];
[_rightView addSubview:self.rightLabel];
//Using PaperFold Framework to Add the Subview (this works fine)
[_paperFoldView setRightFoldContentView:_rightView foldCount:2 pullFactor:1];
//Formatter setup
self.formatter = [[NSDateFormatter alloc] init];
[self.formatter setDateFormat:#"hh:mm:ss"];
}
return self;
}
-(void)updateTimer {
self.rightLabel.text = [self.formatter stringFromDate:[NSDate date]];
}
#end
The #interface DemoRootViewController () part is called a class extension. It essentially allows you "private" properties, so they are not exposed through the header file. If you want them exposed, simply put the two property definitions into the .h file.

Answer 2

Since you want to update the label, make the label variable an instance variable. Then you can create it in the init method and access it in the updateTimer method.
Also, make the date formatter an instance variable so you only need to create it once in the init method. No need to create a new date formatter every half second.
And since your timer should be a private instance variable, remove it from the .h file and put in the .m file.
#implementation DemoRootViewController {
NSTimer *timer;
}
Add the rightLabel and formatter ivars there too.
Also, remove the declaration of updateTimer from the .h file. This is a private method only used by the implementation in the .m file. Adding it to the .h file allows other classes to call the method.

Answer 3

You have to declare UILabel *rightLabel in .h file because you are using rightLabel in another method also.