添加一個NSString到.plist（屬性列表）文件

Question

我試圖閱讀很多問題/教程，但我找不到答案！ 我試圖從一個文本框得到一個字符串，並將其保存在我創建了一個datas.plist文件（默認鍵根目錄下） 我試過這段代碼：

//Save Name to plist 
     if([name.text length] > 0){ 
      NSString *string = name.text; 
      [array addObject:string]; 
      //plist path 
      NSString *path = [[NSBundle mainBundle] pathForResource:@"datas" ofType:@"plist"]; 
      //save object 
      [array writeToFile: path atomically:YES]; 

     } 

其中陣列是

@interface DetailViewController(){ 
    NSMutableArray* array; 
} 

但是當我嘗試應用程序崩潰，以節省給這個錯誤（我連接到一個按鈕之前寫的動作）：

* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Cannot create an NSPersistentStoreCoordinator with a nil model'

我認爲WR代碼它是不正確的，因爲我從來沒有鍵入鑰匙保存（如@「根」）或類似的東西。 在此先感謝

編輯：

我想這代碼，但不寫什麼：

- (void)addToMyPlist { 
    NSString *destPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]; 
    destPath = [destPath stringByAppendingPathComponent:@"dati"]; 

    // If the file doesn't exist in the Documents Folder, copy it. 
    NSFileManager *fileManager = [NSFileManager defaultManager]; 

    if (![fileManager fileExistsAtPath:destPath]) { 
     NSString *sourcePath = [[NSBundle mainBundle] pathForResource:@"dati" ofType:@"plist"]; 
     [fileManager copyItemAtPath:sourcePath toPath:destPath error:nil]; 
    } 

    // Load the Property List. 
    array = [[NSMutableArray alloc] initWithContentsOfFile:destPath]; 

     //NSString *path = [[NSBundle mainBundle] pathForResource:@"dati" ofType:@"plist"]; 
     NSString *string = self.name.text; 

     NSArray *values = [[NSArray alloc] initWithObjects:string, nil]; 
     NSArray *keys = [[NSArray alloc] initWithObjects:@"Root", nil]; 
     NSDictionary *dict = [[NSDictionary alloc] initWithObjects:values forKeys:keys]; 
     [array addObject:dict]; 
     [array writeToFile:destPath atomically:YES]; 
} 

有什麼不對？

Answer 1

包中的所有文件都是隻讀的。

您必須將您的pList移動​​到您的應用程序的私有文檔（或其他文件，其中有3個可用）文件夾才具有寫入權限。

例如，複製文件目錄中的包文件：

if([name.text length] > 0){ 
     NSString *string = name.text; 
     [array addObject:string]; 

     NSFileManager *fileManager = [NSFileManager defaultManager]; 
     NSError *error; 
     //Path to document directory 
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
     NSString *documentsDirectory = [paths objectAtIndex:0]; 

     //Path to your datas.plist inside documents directory 
     NSString *documentsPath = [documentsDirectory stringByAppendingPathComponent:@"datas.plist"]; 

     //If the file doesn't exists yet 
     if ([fileManager fileExistsAtPath:documentsPath] == NO) { 
      //Let's copy it in your Documents folder 
      NSString *bundlePath = [[NSBundle mainBundle] pathForResource:@"datas" ofType:@"plist"]; 

      [fileManager copyItemAtPath:bundlePath toPath:documentsPath error:&error]; 
     } 

     [array writeToFile: documentsPath atomically:YES]; 

    }