我正在嘗試編寫iphone應用程序的Objective-C中工作。如何通知對象?
背景: 有一個導航控制器管理我的視圖控制器。 ViewDidLoad上的我的FirstLevelViewController創建一些SecondLevelViewController對象,將它們存儲在一個數組中,然後在推入各種表格單元格時加載它們。另外,在viewDidLoad上,我的FirstLevelViewController創建一個類的實例來存放關於該對象的變量。這個類可能有多個實例,所以我不想創建一個單例。
各種視圖控制器想要消息數據對象。我怎麼做?第一個levelviewcontroller可以發信息給它,因爲它至少創建了第一個。第二級視圖控制器的行爲就像他們不知道數據對象存在一樣。
我知道它的基本。我知道關於生命,宇宙和一切的意義有很多知識。答案應用程序委託嗎?不是以單例數據存儲方式,而是以類之間的消息方式?我是否需要引用或指針?
我真的很感謝幫助。我已經失去了一個星期的睡眠,並失去了我的彈珠。謝謝。
FirstLevelViewController
#import <Foundation/Foundation.h>
@interface FirstLevelViewController : UITableViewController
<UITableViewDataSource, UITableViewDelegate> {
NSArray *controllers;
}
@property (nonatomic, retain) NSArray *controllers;
@end
#import "FirstLevelViewController.h"
#import "BirthDay.h"
#import "Height.h"
#import "Model.h"
@implementation FirstLevelViewController
@synthesize controllers;
-(void)viewDidLoad {
NSMutableArray *array = [[NSMutableArray alloc]init];
Model *frank = [[Model alloc]init];
frank.date = @"Oh No You Didn't";
self.title = [frank date];
BirthDay *birthday = [[BirthDay alloc]initWithNibName:@"Birthday" bundle:nil];
birthday.title = @"Birth Date";
[array addObject:birthday];
[birthday release];
Height *height = [[Height alloc]initWithNibName:@"Height" bundle:nil];
height.title = @"Height";
[array addObject:height];
[height release];
self.controllers = array;
ModelClass(數據類)
#import <Foundation/Foundation.h>
#import "FirstLevelViewController.h"
#import "BirthDay.h"
#import "model.h"
@interface Model : NSObject {
NSString *date;
}
@property (nonatomic, retain) NSString *date;
@end
#import "Model.h"
@implementation Model
@synthesize date;
@end
SecondLevelViewController
@interface BirthDay : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource>{
UILabel *dateLabel;
UIPickerView *datePicker;
}
@property (nonatomic, retain) IBOutlet UILabel *dateLabel;
@property (nonatomic, retain) IBOutlet UIPickerView *datePicker;
@end
#import "BirthDay.h"
#import "FirstLevelViewController.h"
#import "Model.h"
@implementation BirthDay
@synthesize datePicker;
@synthesize dateLabel;
-(IBAction)updateLabel {
NSDate *dateOfBirth = [datePicker date];
NSDate *todaysDate = [NSDate date];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit;
NSDateComponents *components = [gregorian components:unitFlags fromDate:dateOfBirth toDate:todaysDate options:0];
NSInteger months = [components month];
NSInteger days = [components day];
float Months = months;
if (days > 14) {
Months = Months + 0.5;
}
NSString *message = [[NSString alloc]initWithFormat: @"%.1f Months and %d Days old", Months, days];
dateLabel.text = message;
}
@end
(基本上,我想對於更新標籤調用以更新不僅標籤時,但也是名爲弗蘭克的對象。)
我可以直接發送通知給frank嗎? – Justagruvn 2010-06-19 22:52:23