如果你是flash编程师，你改用哪些代码做一个2048

如果我是 Flash 编程师，我会使用 ActionScript 3.0 编写一个 2048 游戏。以下是可能的代码实现：

首先，定义一个 `Tile` 类来表示游戏面板上的每一个方块：

package {
    import flash.display.Sprite;
    import flash.text.TextField;
    import flash.text.TextFormat;
    
    public class Tile extends Sprite {
        private var value:int;
        private var label:TextField;
        
        public function Tile() {
            value = 0;
            draw();
        }
        
        public function setValue(v:int):void {
            value = v;
            draw();
        }
        
        private function draw():void {
            graphics.clear();
            graphics.beginFill(getColor(value));
            graphics.drawRect(0, 0, 100, 100);
            graphics.endFill();
            
            if (value > 0) {
                if (!label) {
                    label = new TextField();
                    label.width = 100;
                    label.height = 100;
                    label.defaultTextFormat = new TextFormat("Arial", 36, 0xFFFFFF, true, null, null, null, null, "center");
                    addChild(label);
                }
                label.text = value.toString();
            } else if (label) {
                removeChild(label);
                label = null;
            }
        }
        
        private function getColor(v:int):uint {
            switch (v) {
                case 2: return 0xEEEEEE;
                case 4: return 0xDDDDDD;
                case 8: return 0xCCCCCC;
                case 16: return 0xBBBBBB;
                case 32: return 0xAAAAAA;
                case 64: return 0x999999;
                case 128: return 0x888888;
                case 256: return 0x777777;
                case 512: return 0x666666;
                case 1024: return 0x555555;
                case 2048: return 0x444444;
                default: return 0xDDDDDD;
            }
        }
    }
}

然后，定义一个 `Board` 类来管理游戏面板：

package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.KeyboardEvent;
    import flash.ui.Keyboard;
    
    public class Board extends Sprite {
        private var tiles:Array;
        private var gameOver:Boolean;
        private var score:int;
        private var scoreText:TextField;
        private var restartText:TextField;
        
        public function Board() {
            tiles = [];
            gameOver = false;
            score = 0;
            addEventListener(Event.ADDED_TO_STAGE, init);
        }
        
        private function init(e:Event):void {
            removeEventListener(Event.ADDED_TO_STAGE, init);
            addEventListener(Event.REMOVED_FROM_STAGE, destroy);
            stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
            
            for (var i:int = 0; i < 4; i++) {
                tiles[i] = [];
                for (var j:int = 0; j < 4; j++) {
                    var tile:Tile = new Tile();
                    tile.x = j * 100;
                    tile.y = i * 100;
                    addChild(tile);
                    tiles[i][j] = tile;
                }
            }
            
            spawnTile();
            spawnTile();
            
            scoreText = new TextField();
            scoreText.x = 400;
            scoreText.y = 20;
            scoreText.width = 200;
            scoreText.height = 50;
            scoreText.defaultTextFormat = new TextFormat("Arial", 24, 0x000000, true, null, null, null, null, "right");
            addChild(scoreText);
            updateScore();
            
            restartText = new TextField();
            restartText.x = 250;
            restartText.y = 300;
            restartText.width = 300;
            restartText.height = 50;
            restartText.defaultTextFormat = new TextFormat("Arial", 36, 0xFF0000, true, null, null, null, null, "center");
            restartText.text = "Press R to restart";
            addChild(restartText);
        }
        
        private function destroy(e:Event):void {
            removeEventListener(Event.REMOVED_FROM_STAGE, destroy);
            stage.removeEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
        }
        
        private function onKeyDown(e:KeyboardEvent):void {
            if (gameOver) {
                if (e.keyCode == Keyboard.R) {
                    restart();
                }
                return;
            }
            
            var moved:Boolean = false;
            
            switch (e.keyCode) {
                case Keyboard.LEFT:
                    moved = moveLeft();
                    break;
                case Keyboard.RIGHT:
                    moved = moveRight();
                    break;
                case Keyboard.UP:
                    moved = moveUp();
                    break;
                case Keyboard.DOWN:
                    moved = moveDown();
                    break;
            }
            
            if (moved) {
                spawnTile();
                checkGameOver();
                updateScore();
            }
        }
        
        private function moveLeft():Boolean {
            var moved:Boolean = false;
            for (var i:int = 0; i < 4; i++) {
                for (var j:int = 1; j < 4; j++) {
                    var tile:Tile = tiles[i][j];
                    if (tile.value > 0) {
                        var k:int = j;
                        while (k > 0 && tiles[i][k - 1].value == 0) {
                            k--;
                        }
                        if (k > 0 && tiles[i][k - 1].value == tile.value) {
                            tiles[i][k - 1].setValue(tile.value * 2);
                            tiles[i][j].setValue(0);
                            score += tile.value * 2;
                            moved = true;
                        } else if (k < j) {
                            tiles[i][k].setValue(tile.value);
                            tiles[i][j].setValue(0);
                            moved = true;
                        }
                    }
                }
            }
            return moved;
        }
        
        private function moveRight():Boolean {
            var moved:Boolean = false;
            for (var i:int = 0; i < 4; i++) {
                for (var j:int = 2; j >= 0; j--) {
                    var tile:Tile = tiles[i][j];
                    if (tile.value > 0) {
                        var k:int = j;
                        while (k < 3 && tiles[i][k + 1].value == 0) {
                            k++;
                        }
                        if (k < 3 && tiles[i][k + 1].value == tile.value) {
                            tiles[i][k + 1].setValue(tile.value * 2);
                            tiles[i][j].setValue(0);
                            score += tile.value * 2;
                            moved = true;
                        } else if (k > j) {
                            tiles[i][k].setValue(tile.value);
                            tiles[i][j].setValue(0);
                            moved = true;
                        }
                    }
                }
            }
            return moved;
        }
        
        private function moveUp():Boolean {
            var moved:Boolean = false;
            for (var j:int = 0; j < 4; j++) {
                for (var i:int = 1; i < 4; i++) {
                    var tile:Tile = tiles[i][j];
                    if (tile.value > 0) {
                        var k:int = i;
                        while (k > 0 && tiles[k - 1][j].value == 0) {
                            k--;
                        }
                        if (k > 0 && tiles[k - 1][j].value == tile.value) {
                            tiles[k - 1][j].setValue(tile.value * 2);
                            tiles[i][j].setValue(0);
                            score += tile.value * 2;
                            moved = true;
                        } else if (k < i) {
                            tiles[k][j].setValue(tile.value);
                            tiles[i][j].setValue(0);
                            moved = true;
                        }
                    }
                }
            }
            return moved;
        }
        
        private function moveDown():Boolean {
            var moved:Boolean = false;
            for (var j:int = 0; j < 4; j++) {
                for (var i:int = 2; i >= 0; i--) {
                    var tile:Tile = tiles[i][j];
                    if (tile.value > 0) {
                        var k:int = i;
                        while (k < 3 && tiles[k + 1][j].value == 0) {
                            k++;
                        }
                        if (k < 3 && tiles[k + 1][j].value == tile.value) {
                            tiles[k + 1][j].setValue(tile.value * 2);
                            tiles[i][j].setValue(0);
                            score += tile.value * 2;
                            moved = true;
                        } else if (k > i) {
                            tiles[k][j].setValue(tile.value);
                            tiles[i][j].setValue(0);
                            moved = true;
                        }
                    }
                }
            }
            return moved;
        }
        
        private function spawnTile():void {
            var emptyTiles:Array = [];
            for (var i:int = 0; i < 4; i++) {
                for (var j:int = 0; j < 4; j++) {
                    if (tiles[i][j].value == 0) {
                        emptyTiles.push({x: i, y: j});
                    }
                }
            }
            if (emptyTiles.length == 0) {
                return;
            }
            var index:int = Math.floor(Math.random() * emptyTiles.length);
            var value:int = Math.random() < 0.9 ? 2 : 4;
            tiles[emptyTiles[index].x][emptyTiles[index].y].setValue(value);
        }
        
        private function checkGameOver():void {
            gameOver = true;
            for (var i:int = 0; i < 4; i++) {
                for (var j:int = 0; j < 4; j++) {
                    if (tiles[i][j].value == 0) {
                        gameOver = false;
                        return;
                    }
                    if (i > 0 && tiles[i - 1][j].value == tiles[i][j].value) {
                        gameOver = false;
                        return;
                    }
                    if (i < 3 && tiles[i + 1][j].value == tiles[i][j].value) {
                        gameOver = false;
                        return;
                    }
                    if (j > 0 && tiles[i][j - 1].value == tiles[i][j].value) {
                        gameOver = false;
                        return;
                    }
                    if (j < 3 && tiles[i][j + 1].value == tiles[i][j].value) {
                        gameOver = false;
                        return;
                    }
                }
            }
        }
        
        private function updateScore():void {
            scoreText.text = "Score: " + score.toString();
        }
        
        private function restart():void {
            gameOver = false;
            score = 0;
            updateScore();
            for (var i:int = 0; i < 4; i++) {
                for (var j:int = 0; j < 4; j++) {
                    tiles[i][j].setValue(0);
                }
            }
            spawnTile();
            spawnTile();
            removeChild(restartText);
        }
    }
}

最后，在主场景中创建一个 `Board` 对象：

var board:Board = new Board();
addChild(board);

这样就完成了一个简单的 2048 游戏！