xcode更新NSMutableArray

Question

我有一個全局的NSMutableArray，我需要用值更新它。 NSMutableArray在.h中定義如下：

@property (strong, nonatomic) NSMutableArray *myDetails; 

在viewDidLoad中預先填充像這樣;

NSDictionary *row1 = [[NSDictionary alloc] initWithObjectsAndKeys:@"1", @"rowNumber", @"125", @"yards", nil]; 
    NSDictionary *row2 = [[NSDictionary alloc] initWithObjectsAndKeys:@"2", @"rowNumber", @"325", @"yards", nil]; 
    NSDictionary *row3 = [[NSDictionary alloc] initWithObjectsAndKeys:@"3", @"rowNumber", @"525", @"yards", nil]; 
self.myDetails = [[NSMutableArray alloc] initWithObjects:row1, row2, row3, nil]; 

然後，當用戶更改文本字段時，此代碼運行此;

-(void)textFieldDidEndEditing:(UITextField *)textField{ 
    NSObject *rowData = [self.myDetails objectAtIndex:selectedRow]; 

    NSString *yards = textField.text; 

    [rowData setValue:yards forKey:@"yards"]; 

    [self.myDetails replaceObjectAtIndex:selectedRow withObject:rowData]; 
} 

當單步執行代碼時[rowData setValue：yards forKey：@「yards」];它返回這個錯誤;

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object' 

Answer 1

該數組是可變的，但它是什麼... NSDictionary ...不是。你搶的對象從數組中......

NSObject *rowData = [self.myDetails objectAtIndex:selectedRow]; 

，然後你嘗試變異那個對象......

[rowData setValue:yards forKey:@"yards"]; 

數組中的對象是要改變的東西...它是NSDictionary，不可變的，你不能改變它。如果你希望字典是可變的，你必須使用NSMutableDictionary