ios - 在不同的 UIViewController 上管理多个 NSArrays？

Question

是否可以在不同的 View Controller 上管理多个 NSArrays？

这是我的例子:

我目前正在使用两个 View Controller :

TableViewController 用作主菜单。我设置了多个 UIButtons，每个都有一个标签，当用户按下按钮时，它会将它们带到 TableOneViewController。

在 TableOneViewController 中，到目前为止，我已经设置了一个 UIImageView 和一个 UIButton，每次用户按下按钮时，< strong>UIImageView 通过 NSArray 更改图像。

我想使用TableViewController 上的标签 来管理TableOneViewController 的NSArrays。这可能吗？到目前为止，我的代码不起作用。

这是代码。谢谢!

TableViewController.m

- (IBAction)tableSelection:(id)sender
{

    TableOneViewController *TOVC = [self.storyboard instantiateViewControllerWithIdentifier:@"TableOneViewController"];


    if ([sender tag] == 1) {
        [[NSUserDefaults standardUserDefaults] setObject:TOVC.numOne forKey:@"num"];
        [[NSUserDefaults standardUserDefaults] setObject:@"1.png" forKey:@"num2"];

    }


    if ([sender tag] == 2) {
        [[NSUserDefaults standardUserDefaults] setObject:TOVC.numTwo forKey:@"num"];
        [[NSUserDefaults standardUserDefaults] setObject:@"2.png" forKey:@"num2"];

    }

    if ([sender tag] == 3) {
        [[NSUserDefaults standardUserDefaults] setObject:TOVC.numThree forKey:@"num"];
        [[NSUserDefaults standardUserDefaults] setObject:@"3.png" forKey:@"num2"];

    }


    [self presentViewController:TOVC animated:YES completion:nil];


}

TableOneViewController.m

- (IBAction)nextButton:(id)sender
{
    int index = tableCounter++ % [self.numOne count];
    self.num.image = self.numOne[index];
}

- (void)viewDidLoad
{

    self.num.image = [UIImage imageNamed:[[NSUserDefaults standardUserDefaults] objectForKey:@"num"]];
    self.num2.image = [UIImage imageNamed:[[NSUserDefaults standardUserDefaults] objectForKey:@"num2"]];




    [super viewDidLoad];

    tableCounter = 10;

    self.numOne = [NSArray arrayWithObjects:
                   [UIImage imageNamed:@"2.png"],
                   [UIImage imageNamed:@"3.png"],
                   [UIImage imageNamed:@"4.png"],
                   [UIImage imageNamed:@"5.png"],
                   [UIImage imageNamed:@"6.png"],
                   [UIImage imageNamed:@"7.png"],
                   [UIImage imageNamed:@"8.png"],
                   [UIImage imageNamed:@"9.png"],
                   [UIImage imageNamed:@"10.png"],
                   [UIImage imageNamed:@"1.png"],
                   nil];

    self.numTwo = [NSArray arrayWithObjects:
                   [UIImage imageNamed:@"20.png"],
                   [UIImage imageNamed:@"30.png"],
                   [UIImage imageNamed:@"40.png"],
                   [UIImage imageNamed:@"50.png"],
                   [UIImage imageNamed:@"60.png"],
                   [UIImage imageNamed:@"70.png"],
                   [UIImage imageNamed:@"80.png"],
                   [UIImage imageNamed:@"90.png"],
                   [UIImage imageNamed:@"100.png"],
                   [UIImage imageNamed:@"10.png"],
                   nil];

    self.numThree = [NSArray arrayWithObjects:
                   [UIImage imageNamed:@"200.png"],
                   [UIImage imageNamed:@"300.png"],
                   [UIImage imageNamed:@"400.png"],
                   [UIImage imageNamed:@"500.png"],
                   [UIImage imageNamed:@"600.png"],
                   [UIImage imageNamed:@"700.png"],
                   [UIImage imageNamed:@"800.png"],
                   [UIImage imageNamed:@"900.png"],
                   [UIImage imageNamed:@"1000.png"],
                   [UIImage imageNamed:@"100.png"],
                   nil];
}

Answer 1

问题是你在呈现 View Controller 之前传递了数组(viewDidLoad 还没有被调用)，然后你呈现它，但是你初始化了 numOne(和其他数组)在 viewDidLoad 中。我建议使用惰性初始化，这里是 numOne 的示例，为其他两个数组编写相同的代码:

- (NSArray*) numOne
{
    if(!_numOne)
    {
       _numOne= [NSArray arrayWithObjects:
                   [UIImage imageNamed:@"2.png"],
                   [UIImage imageNamed:@"3.png"],
                   [UIImage imageNamed:@"4.png"],
                   [UIImage imageNamed:@"5.png"],
                   [UIImage imageNamed:@"6.png"],
                   [UIImage imageNamed:@"7.png"],
                   [UIImage imageNamed:@"8.png"],
                   [UIImage imageNamed:@"9.png"],
                   [UIImage imageNamed:@"10.png"],
                   [UIImage imageNamed:@"1.png"],
                   nil];
    }
    return _numOne;
}

然而这不是 NSUserDefaults 的目的，我认为这种方法是糟糕的设计。最好在 TableOneViewController 中保留一个指向三个数组之一的 ivar(图像名称相同)。

编辑

这就是我实现该机制的方式:指向 TableOneViewController 中三个数组之一的附加属性:

@property (nonatomic, weak) NSArray* currentArray;

根据触发 tableSelection: 的发送者的标签，这个指针应该指向正确的数组:

// TableViewController
- (IBAction)tableSelection:(id)sender
{

    TableOneViewController *TOVC = [self.storyboard instantiateViewControllerWithIdentifier:@"TableOneViewController"];
    switch([sender tag]) {
        case 1:
            TOVC.currentArray= TOVC.numOne;
            break;
        case 2:
            TOVC.currentArray= TOVC.numTwo;
            break;
        case 3:
            TOVC.currentArray= TOVC.numThree;
            break;
        default:
            return;
    }
    [self presentViewController:TOVC animated:YES completion:nil];
}

// TableOneViewController
- (IBAction)nextButton:(id)sender
{
    int index = tableCounter++ % [self.currentArray count];
    self.num.image = self.currentArray[index];
}