ios - 在字典中查找字典键和字典数组

Question

我有一个包含多个NSMutableDictionary对象的数组。

每次填写文本字段并按下提交按钮时：

//The strings
NSString *dateString = @"Date";
NSString *timeString = @"Time";
NSString *typeString = @"Type";

- (IBAction)addData:(id)sender {

[_myDictionary setObject:_dateLabel.text forKey:dateString];
[_myDictionary setObject:_nNumber.text forKey:timeString];
[_myDictionary setObject:_type.text forKey:typeString];

[_myArray addObject:_myDictionary];

[self display]
}

然后我试图在 UItextView 中显示结果（在这个例子中是日期），但我不知道如何。

    -(void)displayData{

    for (int i = 0; i<_myArray.count; i++) {
        [_myArray objectAtIndex:i];
        outputString = [outputString stringByAppendingFormat:@"%@\n",[_myDictionary objectForKey:@"Date"]];

    }
    _myTextView.text = [NSString stringWithFormat:@"%@",outputString];

}

这最终显示了数组中最后一个字典的日期。我什至无法弄清楚如何从特定字典中记录日期。
说[_myArray objectAtIndex:3] [_myDictionary objectForKey:@"Date"]。我将如何记录第三个索引的日期？

希望这是有道理的

EDIT SOLUTION

for (int i = 0; i<_myArray.count; i++)
    {

        outputString = [outputString stringByAppendingFormat:@"%@ %@\n",[[_myArray objectAtIndex:i]objectForKey:@"Date"], [[_myArray objectAtIndex:i]objectForKey:@"Time"]];

    }
    _myTextView.text = [NSString stringWithFormat:@"%@",outputString];

}

感谢所有快速帮助！

Answer 1

for(int i =0 ;i <[array count];i++)
{
  NSLog(@"%@",[[array objectAtIndex:i]allKeys]);
 }

此方法将打印所有键

Answer 2

第一件事是每次向数组添加新对象时都必须分配一个新字典，否则你的字典将只保存最后一个值，所以

 - (IBAction)addData:(id)sender 
 {

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

   [_myDictionary setObject:_dateLabel.text forKey:dateString];
   [_myDictionary setObject:_nNumber.text forKey:timeString];
   [_myDictionary setObject:_type.text forKey:typeString];

   [_myArray addObject:_myDictionary];

   [self display]
}

现在显示值的部分

-(void)displayData
{
   for (int i = 0; i<_myArray.count; i++) 
  {
      NSMutableDictionary *dictionary = [_myArray objectAtIndexPath:i];

      outputString = [outputString stringByAppendingFormat:@"%@\n",[dictionary objectForKey:@"Date"]];

   }
   _myTextView.text = [NSString stringWithFormat:@"%@",outputString]; 

}

Answer 3

尝试

-(void)displayData{
    NSMutableString *outputString = [NSMutableString string];
    for (NSDictionary *dict in _myArray) {
        [outputString stringByAppendingFormat:@"%@\n",dict[@"Date"]];
    }

    _myTextView.text = [NSString stringWithString:outputString];
}

Answer 4

您混合了实例变量和局部变量，并且没有在循环中正确更新。

理想情况下：

1. myArray 将是一个实例变量（就像你现在拥有它一样）。
2. myDictionary 将是您需要的每个方法中的局部变量。

这区分了您的持久数据和您的工作数据。

试试这个：

NSString *dateString = @"Date";
NSString *timeString = @"Time";
NSString *typeString = @"Type";

- (IBAction)addData:(id)sender {

    NSMutableDictionary *dict = [NSMutableDictionary dictionary];

    [dict setObject:_dateLabel.text forKey:dateString];
    [dict setObject:_nNumber.text forKey:timeString];
    [dict setObject:_type.text forKey:typeString];

    [_myArray addObject:dict];

    [self display]
}


-(void)displayData{

    NSString *outputString = @"";

    for (int i = 0; i<_myArray.count; i++) {
        NSDictionary *dict = [_myArray objectAtIndex:i];
        outputString = [outputString stringByAppendingFormat:@"%@\n",[dict objectForKey:@"Date"]];
    }

    _myTextView.text = outputString;
}