积少成多Flash(7) - ActionScript 3.0 交互之鼠标事件和键盘事件

package 
{ 
        import flash.events.Event; 
        import flash.events.KeyboardEvent; 
        import flash.display.MovieClip; 
        import flash.ui.Keyboard; 
        import flash.events.MouseEvent; 
         
        public class Main extends MovieClip 
        { 
                // 保存用户是否按下了上/下/左/右键 
                public var isUp:Boolean = false; 
                public var isDown:Boolean = false; 
                public var isLeft:Boolean = false; 
                public var isRight:Boolean = false; 
                 
                // 每次 ENTER_FRAME 物体所需移动的距离 
                public var step:Number = 5; 
                 
                public function Main() 
                { 
                        // 设置四个用于显示方向的 MovieClip 的初始状态为停在第一帧 
                        btnUp.stop(); 
                        btnDown.stop(); 
                        btnLeft.stop(); 
                        btnRight.stop();                         
                         
                        // 处理按键的按下、放开事件（在舞台上侦测该事件） 
                        stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressHandler); 
                        stage.addEventListener(KeyboardEvent.KEY_UP, keyReleaseHandler); 
                        // 用于响应按键事件的 ENTER_FRAME 
                        this.addEventListener(Event.ENTER_FRAME, enterFrameHandlerForKeyboard); 
                } 
                 
                protected function keyPressHandler(event:KeyboardEvent):void 
                { 
                        // 检测用户按下的键 
                        switch (event.keyCode) 
                        { 
                                case Keyboard.UP:    
                                        isUp = true; 
                                        btnUp.gotoAndStop(2); 
                                        block.rotation = 0; 
                                        break; 
                                         
                                case Keyboard.DOWN: // 按的是“下”键 
                                        isDown = true; // 保存用户的按键信息。即用户正在按“下”键 
                                        btnDown.gotoAndStop(2); // 用于显示方向“下”的 MovieClip 停到第二帧 
                                        block.rotation = 180; // 物体旋转 180 度 
                                        break; 
                                         
                                case Keyboard.LEFT: 
                                        isLeft = true; 
                                        btnLeft.gotoAndStop(2); 
                                        block.rotation = 270; 
                                        break; 
                                         
                                case Keyboard.RIGHT: 
                                        isRight = true; 
                                        btnRight.gotoAndStop(2); 
                                        block.rotation = 90; 
                                        break; 
                        } 
                } 
                 
                protected function keyReleaseHandler(event:KeyboardEvent):void 
                { 
                        // 检测用户放开的键 
                        switch( event.keyCode ) 
                        { 
                                case Keyboard.UP: // 按的是“上”键 
                                        isUp = false; // 保存用户的按键信息。即用户已经不再按“上”键了 
                                        btnUp.gotoAndStop(1); // 用于显示方向“上”的 MovieClip 停到第一帧 
                                        break; 
                                         
                                case Keyboard.DOWN: 
                                        isDown = false; 
                                        btnDown.gotoAndStop(1); 
                                        break; 
                                         
                                case Keyboard.LEFT: 
                                        isLeft = false; 
                                        btnLeft.gotoAndStop(1); 
                                        break; 
                                         
                                case Keyboard.RIGHT: 
                                        isRight = false; 
                                        btnRight.gotoAndStop(1); 
                                        break; 
                        } 
                } 
                 
                protected function enterFrameHandlerForKeyboard(event:Event):void 
                { 
                        // 根据用户的按键情况。将物体向上/下/左/右移动指定的距离 
                        if (isLeft)    
                        { 
                                block.x -= step; 
                        } 
                        if (isRight)    
                        { 
                                block.x += step; 
                        } 
                        if (isUp)    
                        { 
                                block.y -= step; 
                        } 
                        if (isDown)    
                        { 
                                block.y += step; 
                        } 
                } 
        } 
}

package 
{ 
        import flash.events.Event; 
        import flash.events.KeyboardEvent; 
        import flash.display.MovieClip; 
        import flash.ui.Keyboard; 
        import flash.events.MouseEvent; 
         
        public class Main extends MovieClip 
        { 
                // 鼠标单击位置的坐标 
                public var targetX:Number = 0; 
                public var targetY:Number = 0; 
                // 物体是否再向鼠标单击的位置移动 
                public var moving:Boolean = false; 
                 
                // 每次 ENTER_FRAME 物体所需移动的距离 
                public var step:Number = 5; 
                 
                public function Main() 
                { 
                        // 处理鼠标的按下事件（在舞台上侦测该事件） 
                        stage.addEventListener(MouseEvent.MOUSE_DOWN, mouseDownHandler); 
                        // 用于响应鼠标按下事件的 ENTER_FRAME 
                        this.addEventListener(Event.ENTER_FRAME, enterFrameHandlerForMouse); 
                } 
                 
                protected function mouseDownHandler(event:MouseEvent):void 
                { 
                        // 当用户在舞台上按下鼠标后，获取鼠标的坐标 
                        targetX = event.stageX; 
                        targetY = event.stageY; 
                         
                        // 物体正在向鼠标单击的位置移动 
                        moving = true; 
                }                 

                protected function enterFrameHandlerForMouse(event:Event):void 
                { 
                        if (moving) 
                        { 
                                // 计算物体在 X 方向和 Y 方向上分别需要移动的距离 
                                var offsetX:Number = block.x - targetX; 
                                var offsetY:Number = block.y - targetY; 
                                 
                                // 计算物体需要旋转的角度 
                                var targetRotation:Number = -Math.atan2(offsetX, offsetY) / (Math.PI / 180); 
                                block.rotation = targetRotation; 
                                 
                                if( Math.sqrt((offsetX*offsetX) + (offsetY*offsetY)) > step ) 
                                { 
                                        // 如果还没有移动到目标位，则继续移动指定的距离 
                                        block.y -= step * Math.cos(targetRotation * (Math.PI/180)); 
                                        block.x += step * Math.sin(targetRotation * (Math.PI/180)); 
                                } 
                                else 
                                { 
                                        // 物体已经移动到鼠标所单击的位置 
                                        moving = false; 
                                } 
                        } 
                } 
        } 
}