iphone - アプリがフォアグラウンドに入ったときにViewControllerのラベルを変更する方法

Question

アプリがフォアグラウンドに入ったときにビュー コントローラーのラベルを変更したい....:

SalaryAppV4AppDelegate.h

@interface SalaryAppV4AppDelegate : NSObject {

//----------------------------------------------

NSTimeInterval appEnteredBackground;

NSTimeInterval appEnteredForeground;

NSTimeInterval difference;

NSString *times;

//-----------------------------------------------------

SalaryAppV4AppDelegate.m

• (void)applicationWillEnterForeground:(UIApplication *)アプリケーション

{

//perform -(IBAction)DoThis

FirstViewController* controller = [FirstViewController alloc];
[controller DoThis]; 




//releasing
[dateFormatter release];

}

//------------------------------------------------ ----------------------

FirstViewController.h

import UIKit/UIKit.h > import "SalaryAppV4AppDelegate.h"

@interface FirstViewController : UIViewController {

IBOutlet UITextField *text1;
IBOutlet UILabel *label;
IBOutlet UILabel *labeltotal;
IBOutlet UILabel *differenceLabel;


int i;
float number1;
NSTimer *timer;

SalaryAppV4AppDelegate *appDelegate;

}

//行動

-(IBAction)リセット:(id)送信者;

-(IBAction)backgroundTouched:(id)送信者;

-(IBAction) beginTimer;

-(無効) DoThis;

//プロパティ

@終わり

//------------------------------------------------ --------------------

FirstViewController.m

-(IBAction) DoThis {

appDelegate = [[[UIApplication sharedApplication] delegate] retain];

//This Doesn't Work :(
label.text = @"IT Has Worked";


//This Works
NSLog(@"%@", appDelegate.times);

}

//------------------------------------------------ --------

私はちょうどlabel.text tiを何かに変更したいだけですが、viewcontrollerの変更は何もしません...