Question

对于我的iOS应用程序我想启动NSMutableArray并使用按钮更改运行期间数组保存的Object。到目前为止，我能够在ViewController.m中的viewDidLoad {}中启动一个数组，但现在我无法在我的buttonPressed方法中访问它。如何使数组可以访问保存文件？

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    NSMutableArray *toCalculate = [@[@0] mutableCopy];
}


- (IBAction)numbersButtonsPressed:(UIButton *)sender {
    NSLog(@"%ld\n", sender.tag);
    [toCalculate addObject:[NSNumber numberWithLong:sender.tag]];
}

Answer 1

谢谢保罗，如果你在ViewController.h文件中将它实现为@property，它就像他说的那样工作。

   @interface ViewController: UIViewController

   @propety NSMutableArray *giveItAName

   @end

Answer 2

将变量声明为全局（类变量）而不是局部变量（函数）。

What is global variable?

问题的解决方案是：

#import "ViewController.h"

@interface ViewController (){
    NSMutableArray *toCalculate;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    toCalculate = [@[@0] mutableCopy];
    // Do any additional setup after loading the view, typically from a nib.
}



- (IBAction)numbersButtonsPressed:(UIButton *)sender {
    NSLog(@"%@",toCalculate);
    [toCalculate addObject:[NSNumber numberWithLong:sender.tag]];
}


@end

按下按钮时如何在NSMutableArray中添加值

2 个答案: