如何在SpriteKit游戏中获取键盘输入？

Question

我是一名SpriteKit编程的初学者，一直在尝试弄清如何处理来自键盘的输入。

目前我发现，你应该创建一个NSResponder子类并像这样实现它：

@interface AppDelegate : NSResponder <NSApplicationDelegate>
-(void)keyUp:(NSEvent *)theEvent;
-(void)keyDown:(NSEvent *)theEvent;
@end

@implementation AppDelegate
-(void)keyUp:(NSEvent *)theEvent
{
   NSLog(@"Key Released");
}
-(void)keyDown:(NSEvent *)theEvent
{
  NSLog(@"Key Pressed");
}
@end

显然，接口和实现中还有一些方法/属性在AppDelegate中，但我没有将它们放在那里以保持问题的相关性。

接下来，我会开始使用关键代码来检测按下了哪些键，但是keyUp和keyDown方法甚至没有被调用。我不知道为什么。

需要帮助吗？

更新： 谢谢你们的答案！我发现你必须直接在场景类中实现keyUp和keyDown，因为它们不会从AppDelegate中调用。再次感谢您的帮助！

- Dovahkiin

Answer 1

我知道的最简单的方法是在你的SKScene中实现keyDown方法（而不是直接在AppDelegate中）。你不需要子类化任何东西。

- (void)keyDown:(NSEvent *)event {
    [self handleKeyEvent:event keyDown:YES];
}

- (void)keyUp:(NSEvent *)event {
    [self handleKeyEvent:event keyDown:NO];
}

然后使用方法handleKeyEvent:(NSEvent *)event keyDown:(BOOL)downOrUp来检查按下了哪个键：

- (void)handleKeyEvent:(NSEvent *)event keyDown:(BOOL)downOrUp {
    // First check the arrow keys since they are on the numeric keypad.
    if ([event modifierFlags] & NSNumericPadKeyMask) { // arrow keys have this mask
        NSString *theArrow = [event charactersIgnoringModifiers];
        unichar keyChar = 0;
        if ([theArrow length] == 1) {
            keyChar = [theArrow characterAtIndex:0];
            switch (keyChar) {
                case NSUpArrowFunctionKey:
                    self.defaultPlayer.moveForward = downOrUp;
                    break;
                case NSLeftArrowFunctionKey:
                    self.defaultPlayer.moveLeft = downOrUp;
                    break;
                case NSRightArrowFunctionKey:
                    self.defaultPlayer.moveRight = downOrUp;
                    break;
                case NSDownArrowFunctionKey:
                    self.defaultPlayer.moveBack = downOrUp;
                    break;
            }
        }
    }

    // Now check the rest of the keyboard
    NSString *characters = [event characters];
    for (int s = 0; s<[characters length]; s++) {
        unichar character = [characters characterAtIndex:s];
        switch (character) {
            case 'w':
                self.defaultPlayer.moveForward = downOrUp;
                break;
            case 'a':
                self.defaultPlayer.moveLeft = downOrUp;
                break;
            case 'd':
                self.defaultPlayer.moveRight = downOrUp;
                break;
            case 's':
                self.defaultPlayer.moveBack = downOrUp;
                break;
            case ' ':
                self.defaultPlayer.fireAction = downOrUp;
                break;
        }
    }
}

我从苹果的SpriteKit Adventure游戏中获取了这段代码。我发现它对学习SpriteKit非常有用 :)

- Heyfara

Answer 2

以下是HeyFara答案的Swift (2.0)版本。我只是在你实际调用函数的位置加入了"breaks"。

    public override func keyDown(theEvent: NSEvent) {
    handleKeyEvent(theEvent, keyDown: true)
}

public override func keyUp(theEvent: NSEvent) {
    handleKeyEvent(theEvent, keyDown: false)
}

public func handleKeyEvent(event:NSEvent, keyDown:Bool){
    if event.modifierFlags.contains(NSEventModifierFlags.NumericPadKeyMask){
        if let theArrow = event.charactersIgnoringModifiers, keyChar = theArrow.unicodeScalars.first?.value{
            switch Int(keyChar){
            case NSUpArrowFunctionKey:
                break
            case NSDownArrowFunctionKey:
                break
            case NSRightArrowFunctionKey:
                break
            case NSLeftArrowFunctionKey:
                break
            default:
                break
            }
        }
    } else {
        if let characters = event.characters{
            for character in characters.characters{
                switch(character){
                case "w":
                    break
                default:
                    print(character)
                }
            }
        }
    }
}

- rougeExciter

Answer 3

这是HeyFara的回答的rougeExciter版本，但是用Swift 4.2编写...以防有人发现这篇旧帖子...就像几分钟前的我一样 :)...

public override func keyDown(with event: NSEvent) {
    handleKeyEvent(event, keyDown: true)
}

public override func keyUp(with event: NSEvent) {
    handleKeyEvent(event, keyDown: false)
}

public func handleKeyEvent(_ event: NSEvent, keyDown: Bool){
    if event.modifierFlags.contains(NSEvent.ModifierFlags.numericPad) {
        if let theArrow = event.charactersIgnoringModifiers, let keyChar = theArrow.unicodeScalars.first?.value{
            switch Int(keyChar){
            case NSUpArrowFunctionKey:
                break
            case NSDownArrowFunctionKey:
                break
            case NSRightArrowFunctionKey:
                break
            case NSLeftArrowFunctionKey:
                break
            default:
                break
            }
        }
    } else {
        if let characters = event.characters{
            for character in characters {
                switch(character){
                case "w":
                    break
                default:
                    print(character)
                }
            }
        }
    }
}

- Beny

Answer 4

如果你想知道何时按下了某个键，你应该订阅全局事件管理器。

[NSEvent addGlobalMonitorForEventsMatchingMask:(NSKeyDownMask) handler:^(NSEvent *event) {
[NSEvent removeMonitor:event];

每当有键被按下，这将调用处理程序。

- user3339357