xcode更新NSMutableArray

Question

我有一个全局的NSMutableArray，我需要用值更新它。 NSMutableArray在.h中定义如下：

@property (strong, nonatomic) NSMutableArray *myDetails; 

在viewDidLoad中预先填充像这样;

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]; 

然后，当用户更改文本字段时，此代码运行此;

-(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]; 
} 

当单步执行代码时[rowData setValue：yards forKey：@“yards”];它返回这个错误;

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

Answer 1

该数组是可变的，但它是什么... NSDictionary ...不是。你抢的对象从数组中......

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

，然后你尝试变异那个对象......

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

数组中的对象是要改变的东西...它是NSDictionary，不可变的，你不能改变它。如果你希望字典是可变的，你必须使用NSMutableDictionary