Question

I’m hacking on a simple Cocoa app to make blocks move around the screen like a video game. I need to detect key presses, but I’m not going to have text entry fields like a dialog box would have.

How do I get key presses without text controls? In particular, I need to get arrow keys.

Answer 1

In your game view, define the keyUp and keyDown methods:

@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 

See the documentation for NSView and NSEvent for more info. Note that the keyDown and keyUp events are actually defined on NSResponder, the super class for NSView.