引用另一个方法objective-c中的变量

Question

我是Obj-C的新手，如果问题很明显，我很抱歉！

无论如何，我只是进入objective-c，并试图创建一个基本的iOS计数器，每次用户单击/触摸UI时，都会增加一个点计数器。

我已经创建了currentScore int，可以将其记录到控制台。我还成功地将UI的每次触摸记录到控制台。

我现在要做的是，在每次触摸时访问currentScore int，并将int递增1。

正如我所说，可能很容易，但不能100%确定如何在其他函数中引用其他变量！

提前谢谢。

//
//  JPMyScene.m
//
#import "JPMyScene.h"
@implementation JPMyScene
-(id)initWithSize:(CGSize)size {    
    if (self = [super initWithSize:size]) {
        /* Setup your scene here */
        self.backgroundColor = [UIColor redColor];
        //Initiate a integer point counter, at 0.
        int currentScore = 0;
        NSLog(@"Your score is: %d", currentScore);
    }
    return self;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    /* Called when a touch begins */
    for (UITouch *touch in touches) {
        NSLog(@"Tap, tap, tap");
        //TODO: For each tap, increment currentScore int by 1
    }
}
-(void)update:(CFTimeInterval)currentTime {
    /* Called before each frame is rendered */
}
@end

Answer 1

首先在interface.h接口中将整数声明为全局变量或属性。然后从任意位置进行访问和修改。这是您的界面和实现：

@interface JPMyScene
{
int currentScore;
}
@end
@implementation JPMyScene
-(id)initWithSize:(CGSize)size {    
    if (self = [super initWithSize:size]) {
        self.backgroundColor = [UIColor redColor];
        currentScore = 0;
        NSLog(@"Your score is: %d", currentScore);
    }
  return self;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
     for (UITouch *touch in touches) {
        NSLog(@"Tap, tap, tap");
        currentScore++;
     }
}
-(void)update:(CFTimeInterval)currentTime {
}

Answer 2

您的问题与ObjC无关，而是与OOP有关。基本上，您需要一个在对象的多个方法中可用的变量。解决方案是将currentScore声明为JPMyScene的实例变量。

Answer 3

将currentScore变量更改为全局变量，如本代码所示。

//
//  JPMyScene.m
//
#import "JPMyScene.h"
@implementation JPMyScene
int currentScore = 0;
-(id)initWithSize:(CGSize)size {
            /* Setup your scene here */
        self.view.backgroundColor = [UIColor redColor];
        //Initiate a integer point counter, at 0.

        NSLog(@"Your score is: %d", currentScore);
    return self;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    /* Called when a touch begins */
    for (UITouch *touch in touches) {
        NSLog(@"Tap, tap, tap");
        currentScore++;
       NSLog(@"Your score is: %d", currentScore);
        //TODO: For each tap, increment currentScore int by 1
    }
}
-(void)update:(CFTimeInterval)currentTime {
    /* Called before each frame is rendered */
}
@end