如何在视频游戏风格的Cocoa应用程序中收集键输入？

Question

我正在攻击一个简单的Cocoa应用程序,以便像电子游戏一样让屏幕在屏幕上移动.我需要检测按键,但我不会像对话框那样有文本输入字段.

如何在没有文本控件的情况下获得按键操作？特别是,我需要获得箭头键.

Answer 1

在游戏视图中,定义keyUp和keyDown方法:

@interface MyView : NSView
-(void)keyUp:(NSEvent*)event;
-(void)keyDown:(NSEvent*)event;
@end

@implementation MyView

-(void)keyUp:(NSEvent*)event
{
    NSLog(@"Key released: %@", event);
}

-(void)keyDown:(NSEvent*)event
{   
    // I added these based on the addition to your question :)
    switch( [event keyCode] ) {
        case 126:   // up arrow
        case 125:   // down arrow
        case 124:   // right arrow
        case 123:   // left arrow
            NSLog(@"Arrow key pressed!");
            break;
        default:
            NSLog(@"Key pressed: %@", event);
            break;
    }
}
@end

有关详细信息,请参阅NSView和NSEvent的文档.请注意,keyDown和keyUp事件实际上是在NSResponder(NSView的超类)上定义的.