使用@property將值從一個類傳遞到另一個類使用@property

Question

我一直在下拉我的頭髮，試圖弄清楚爲什麼下面的代碼不起作用。我所要做的就是傳遞一個字符串，從一個類到另一個類。

在我FirstDetailViewController.h文件我宣佈NSString的

@property(nonatomic, retain) NSString *infoForArray; 

然後在我的Grinding01_DetailViewController.m我嘗試的字符串

#import "Grinding01_DetailViewController.h" 
#import "FirstDetailViewController.h" 

@implementation Grinding01_DetailViewController 


... 

    NSString *didLoadMessage = @"Grinding01 Loaded"; 

    FirstDetailViewController *temp = [[FirstDetailViewController alloc] initWithNibName:@"FirstDetailView" bundle:nil]; 

    temp.infoForArray = didLoadMessage; 

    [self.navigationController pushViewController:temp animated:YES]; 

} 

設定的值。當我輸出的infoForArray從FirstDetailViewController.h它是空的。

任何幫助將不勝感激，我認爲有一個簡單的步驟，我失蹤，但我只是看不到它。

---

編輯：下面是來自FirstDetailViewController

FirstDetailViewController.h

#import <UIKit/UIKit.h> 
#import "Protocols.h" 

@interface FirstDetailViewController : UIViewController <SubstitutableDetailViewController> { 

    //for the output 
    IBOutlet UITextView *outputView; 

    UIToolbar *navigationBar; 

    NSMutableArray *logMessages; 

} 

@property (nonatomic, retain) IBOutlet UIToolbar *navigationBar; 

//for incoming messages 
@property(nonatomic, retain) NSString *infoForArray; 


@end 

FirstDetailViewController.m

#import "FirstDetailViewController.h" 

@implementation FirstDetailViewController 

@synthesize navigationBar, infoForArray; 

-(void)viewDidLoad{ 

    [super viewDidLoad]; 

    //The log cannot be changed 
    outputView.editable = NO;  

} 


#pragma mark - 
#pragma mark View lifecycle 

- (void)viewDidUnload { 

    [super viewDidUnload]; 

    self.navigationBar = nil; 

} 

-(void)viewWillAppear:(BOOL)animated{ 

    [super viewWillAppear:YES]; 

    NSLog(@"message: %@", infoForArray); 

    outputView.text = infoForArray; 

} 

#pragma mark - 
#pragma mark Managing the popover 

- (void)showRootPopoverButtonItem:(UIBarButtonItem *)barButtonItem { 

    // Add the popover button to the toolbar. 
    NSMutableArray *itemsArray = [navigationBar.items mutableCopy]; 
    [itemsArray insertObject:barButtonItem atIndex:0]; 
    [navigationBar setItems:itemsArray animated:NO]; 
    [itemsArray release]; 
} 


- (void)invalidateRootPopoverButtonItem:(UIBarButtonItem *)barButtonItem { 

    // Remove the popover button from the toolbar. 
    NSMutableArray *itemsArray = [navigationBar.items mutableCopy]; 
    [itemsArray removeObject:barButtonItem]; 
    [navigationBar setItems:itemsArray animated:NO]; 
    [itemsArray release]; 
} 


#pragma mark - 
#pragma mark Rotation support 

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { 
    return YES; 
} 


#pragma mark - 
#pragma mark Memory management 

- (void)dealloc { 
    [navigationBar release]; 
    [super dealloc]; 
} 


@end 

Answer 1

這聽起來像麻煩的區域是在FirstDetailViewController。我會建議發佈代碼，以便我們可以看到發生了什麼。

Answer 2

我的猜測是，你在什麼地方檢查infoForArray代碼FirstDetailViewController的實例化過程發生s之前，你設置temp.infoForArray = didLoadMessage。

僅供參考，如果您在viewDidLoad中檢查infoForArray，那就太早了。 viewDidLoad將視圖放入內存時觸發。你想要的是viewDidAppear，你可能需要添加自己