爲什麼plist中的項目被覆蓋？

Question

我想添加一個新項目給我的plist。但是，每當我按下保存時它都會被覆蓋：

-(IBAction)save:(id)sender { 

appDelegate = (JobTestAppDelegate*)[[UIApplication sharedApplication]delegate]; 

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"Work.plist"]; 

NSMutableDictionary* newNote = [[NSMutableDictionary alloc] init]; 

NSMutableDictionary *set = [NSMutableDictionary dictionaryWithObjects:[NSArray arrayWithObjects:@"", @"", nil] forKeys:[NSArray arrayWithObjects:@"Work Name", @"Work ID", nil]]; 

NSArray *work = [NSArray arrayWithObjects:set, nil]; 

int row = 0; 
newNote = [appDelegate.job objectAtIndex:row]; 
[newNote setValue:work forKey:@"Work"];   

[appDelegate.job writeToFile:fileName atomically:TRUE]; 

[newNote release]; 

[self dismissModalViewControllerAnimated:YES]; 
} 

我不知道哪部分代碼是錯誤的。我一直在努力解決這個問題好幾天。

編輯： appDelegate.job - 在我的主要應用程序委託類的可變數組創建的plist：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"Work.plist"]; 

job = [[NSMutableArray alloc] initWithContentsOfFile:fileName]; 


[job writeToFile:fileName atomically:YES]; 

EDIT2：

我需要存儲的用戶輸入（NSArray的*作）進入工作陣列

根（陣列）

 Item 0 (Dict) 
         Name (String) 
         Work (Array) 
             Item 0 (Dict) 
                Work Name (String) 
                Work ID (String) 
             Item 1 (Dict) 
                Work Name (String) 
                Work ID (String) 
     Item 1 (Dict) 
         Name (String) 
         Analysis (Array) 
             Item 0 (Dict) 
                Work Name (String) 
                Work ID (String) 
             Item 1 (Dict) 
                Work Name (String) 
                Work ID (String) 

編輯3： NSMutableDictionary * newNote = [[NSMutableDictionary alloc] init];

NSMutableDictionary *set = [NSMutableDictionary dictionaryWithObjects:[NSArray arrayWithObjects:@"", @"", nil] forKeys:[NSArray arrayWithObjects:@"Work Name", @"Work ID", nil]]; 

NSArray *work = [NSArray arrayWithObjects:set, nil]; 

int row = item; 
newNote = [appDelegate.job objectAtIndex:row]; 
[newNote setValue:work forKey:@"Work"];   

//i think this is the line which i am having problem with. 
//without this line my data in the plist gets overwritten, 
//with this code it copies the who item and create a new item into my root array 
[appDelegate.job addObject:newNote]; 

[appDelegate.job writeToFile:fileName atomically:TRUE]; 

[newNote release]; 

由於事先 李亞男

Answer 1

您將要覆蓋不管是在工作指數爲零的新項目。你也在這裏分配內存：

NSMutableDictionary* newNote = [[NSMutableDictionary alloc] init]; 

然後再分配別的東西給這個變量在這裏：

newNote = [appDelegate.job objectAtIndex:row]; 

如果你想添加一個新的項目，你應該做的是這樣的：

NSMutableDictionary* newNote = [[NSMutableDictionary alloc] init]; 
[newNote setValue:work forKey:@"Work"]; 
[appDelegate.job addObject:newNote]; 
[appDelegate.job writeToFile:fileName atomically:TRUE]; 

然後，您將新的字典添加到您的作業數組，並寫出整個數組。

編輯：從您的意見，它看起來像newNote應該是一個字典，一個名稱和一個數組。所以，你需要添加一個新的對象到現有的數組中 - 你正在設置一個單一的數組作爲這個字典的「工作」鍵。

你需要的東西，如：

NSMutableDictionary* newNote = [appDelegate.job objectAtIndex:0]; 
NSArray *oldWork = [newNote objectForKey:@"Work"]; 
NSArray *newWork = [oldWork arrayByAddingObject:set]; 
[newNote setObject:newWork forKey:@"Work"];