SpriteKit - 创建一个计时器 [英] SpriteKit - Creating a timer

问题描述

如何创建一个计时器，每两秒触发一次，将我在屏幕上的HUD上的分数增加一个？这是我对HUD的代码：

How can I create a timer that fires every two seconds that will increment the score by one on a HUD I have on my screen? This is the code I have for the HUD:

    @implementation MyScene
{
    int counter;
    BOOL updateLabel;
    SKLabelNode *counterLabel;
}

-(id)initWithSize:(CGSize)size
{
    if (self = [super initWithSize:size])
    {
        counter = 0;

        updateLabel = false;

        counterLabel = [SKLabelNode labelNodeWithFontNamed:@"Chalkduster"];
        counterLabel.name = @"myCounterLabel";
        counterLabel.text = @"0";
        counterLabel.fontSize = 20;
        counterLabel.fontColor = [SKColor yellowColor];
        counterLabel.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeCenter;
        counterLabel.verticalAlignmentMode = SKLabelVerticalAlignmentModeBottom;
        counterLabel.position = CGPointMake(50,50); // change x,y to location you want
        counterLabel.zPosition = 900;
        [self addChild: counterLabel];
    }
}

推荐答案

In Sprite Kit 不使用 NSTimer ， performSelector：afterDelay：或Grand Central Dispatch（GCD） ，即任何 dispatch _... 方法）因为这些计时方法忽略节点，场景或视图的暂停状态。此外，你不知道它们在游戏循环中的哪个位置被执行，这可能会导致各种问题，具体取决于你的代码实际做了什么。

In Sprite Kit do not use NSTimer, performSelector:afterDelay: or Grand Central Dispatch (GCD, ie any dispatch_... method) because these timing methods ignore a node's, scene's or the view's paused state. Moreover you do not know at which point in the game loop they are executed which can cause a variety of issues depending on what your code actually does.

只有两个受制裁的方式在Sprite Kit中执行基于时间的操作是使用SKScene update：方法并使用传入的currentTime参数来跟踪时间。

The only two sanctioned ways to perform something time-based in Sprite Kit is to either use the SKScene update: method and using the passed-in currentTime parameter to keep track of time.

或者更常见的是你会使用以等待动作开头的动作序列：

Or more commonly you would just use an action sequence that starts with a wait action:

id wait = [SKAction waitForDuration:2.5];
id run = [SKAction runBlock:^{
    // your code here ...
}];
[node runAction:[SKAction sequence:@[wait, run]]];

并重复运行代码：

[node runAction:[SKAction repeatActionForever:[SKAction sequence:@[wait, run]]]];

或者你也可以使用 performSelector：onTarget：而不是 runBlock：或者使用 customActionWithDuration：actionBlock：如果你需要模仿SKScene 更新：方法，不知道如何将其转发到节点或转发不方便的地方。

Alternatively you can also use performSelector:onTarget: instead of runBlock: or perhaps use a customActionWithDuration:actionBlock: if you need to mimick the SKScene update: method and don't know how to forward it to the node or where forwarding would be inconvenient.

参见 SKAction参考了解详情。

更新：使用Swift的代码示例

UPDATE: Code examples using Swift

Swift 3

let wait = SKAction.wait(forDuration:2.5)
let action = SKAction.run {
    // your code here ...
}
run(SKAction.sequence([wait,action]))

Swift 2

let wait = SKAction.waitForDuration(2.5)
let run = SKAction.runBlock {
    // your code here ...
}
runAction(SKAction.sequence([wait, run]))

Aund重复运行代码：

Aund to run the code repeatedly:

runAction(SKAction.repeatActionForever(SKAction.sequence([wait, run])))

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