How to call ViewController's UILabel in Singleton - ios

Question

I asked a question：link
After discussing this issue, I will rewrite the original program, become Singleton methods.
I'll call timer which way to write in MySingleton,then TimerViewController inside to call MySingleton's method :
MySingleton.h
#interface MySingleton : NSObject
{
int remainder;
NSTimer *timer;
NSTimeInterval countDownInterval;
int hours;
int mins;
int secs;
}
#property(nonatomic, retain)NSString *displayText;
#property int afterRemainder;
+(MySingleton*) getInstance;
-(void)doSomethingWithString:(int*)parameter;
#end
MySingleton.m
-(void)doSomethingWithString:(int*)parameter {
remainder = *parameter;
_afterRemainder = *parameter - remainder % 60 ;
timer=[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:#selector(updateCountDown)userInfo:nil repeats:YES];
}
-(void)updateCountDown{
_afterRemainder --;
hours = (int)(_afterRemainder/(60*60));
mins = (int)(((int)_afterRemainder/60)-(hours * 60));
secs = (int)(((int)_afterRemainder - (60 * mins) - (60 * hours *60)));
displayText = [[NSString alloc]initWithFormat:#"%02u : %02u : %02u",hours,mins,secs];
}
TimerViewController.h
#interface TimerViewController : UIViewController
#property (retain, nonatomic) IBOutlet UIDatePicker *CountDown;
#property (retain, nonatomic) IBOutlet UILabel *LabTimer;
#property (retain, nonatomic) IBOutlet UIButton *BtnStart;
- (IBAction)StartCmd:(id)sender;
#end
TimerViewController.m
Here to call timer,UILabel is placed TimerViewController.m
- (IBAction)StartCmd:(id)sender {
MySingleton* singleton = [MySingleton getInstance];
nowInterval=(NSTimeInterval)CountDown.countDownDuration;
nowTimer = nowInterval;
[singleton doSomethingWithString:&(nowTimer)];
}
TimerViewContorller have one Label call LabTimer, MySingleton have a NSString call display text I want to call LabTimer in MySingleton,and displays displaytext in LabTimer
I don't know how to do it?

Answer 1

don't understand u're question. But show u how singleton may work.
so:
u have some Singleton class: MySingleton.
h.file
#interface MySingleton : NSObject {
}
+ (id)sharedManager;
- (void)SomeMethod:(int)someParameter;
#end
m file
#implementation MySingleton
+ (id)sharedManager {
static MySingleton *sharedMyManager = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedMyManager = [[self alloc] init];
});
return sharedMyManager;
}
#pragma mark - Some public Method
- (void)SomeMethod:(int)someParameter
{
// code here
[self somePrivateMethod];
}
#pragma mark - Some private Method
- (void)somePrivateMethod {
// code here
}
And u can use this class inside u're MainClassController:
like this:
// some code before
/* call singleton `Some Method` */
[[MySingleton sharedManager] SomeMethod:'int value'];
// code after
Maybe its helps u . Good luck)

Answer 2

You need to set the text of the UILabel when the timer fires. Move the assignment statement that assigns displayText into the timer's action method (updateCountDown).
By the way, I don't understand UILabel.text = ... I assume that this is a syntax error in your code.
When you do an assignment like this:
myLabel.text = displayText;
what happens is that the right-hand side expression (a single variable in this case) is evaluated and its value at the time the statement is executed is assigned to the text property of the UILabel (and the user sees it). If you change the value of displayText later, that will make no difference to what the user sees - the assignment to the text property has to be executed again. I hope this is clear.
To solve your problem:
Add a weak reference to TimeViewController to MySingleton:
#property (weak) TimeViewController* myViewController;
Before calling doSomethingWithString, assign self to singleton
MySingleton* singleton = [MySingleton getInstance];
nowInterval=(NSTimeInterval)CountDown.countDownDuration; nowTimer =
nowInterval; singleton.myViewController = self; [singleton
doSomethingWithString:&(nowTimer)];
Whenever the timer fires, call a method of TimeViewController
... displayText = [[NSString alloc]initWithFormat:#"%02u : %02u :
%02u",hours,mins,secs]; [self.myViewController
updateDisplay:displayText];