g2048游戏2-android

接着上一篇g2048游戏1-android

g2048主界面

主界面（MainView）其实就是需要绘制表格，首要考虑android自带的ShapeDrawable资源。
MainView需要绘制：
1：整个表格背景background_rectangle.xml
2：每一小格背景

• 小格无数字背景cell_rectangle.xml
• 小格有数字x背景cell_rectangle_x.xml
• 绘制背景上的数字canvas.drawText

主界面MainView

j\i 0 1 2 3 0 4 2 1 4 2 2 3 2

MainView需要自定义，在该类中只负责绘制，而数据逻辑交给辅助MainGame .java

背景使用ShapeDrawable

整个表格背景background_rectangle.xml
小格无数字背景cell_rectangle.xml
小格有数字x背景cell_rectangle_x.xml

这个三个背景是一样的，都使用ShapeDrawable，只是颜色背景不一样

如background_rectangle.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="rectangle" android:padding = "10dp">    <solid android:color="#bbada0"/>    <corners        android:bottomRightRadius="10dp"        android:bottomLeftRadius="10dp"        android:topLeftRadius="10dp"        android:topRightRadius="10dp"/></shape>

其他背景颜色
color=”#d6cdc4”
color=”#eee4da”
color=”#ede0c8”
color=”#f2b179”
color=”#f59563”
color=”#f67c5f”
color=”#f65e3b”
color=”#edcf72”
color=”#edcc61”
color=”#edc850”
color=”#edc53f”
color=”#edc22e”

自定义MainView

其中MainGame 对象负责数据逻辑，GestureDetector手势对象负责监听上下左右滑动

public class MainView extends View {    public MainGame game;    private GestureDetector gesture;    private int numCellTypes = 13;    // Layout    private Paint paint = new Paint();    private int cellSize;    private int gridWidth;    private float textSize;    private float cellTextSize;    private int startX;    private int endX;    private int startY;    private int endY;    // Text    private int TEXT_WHITE;    private int TEXT_BLACK;    // asssets drawable    private Drawable backgroundRectangle;    private BitmapDrawable[] bitmapCell = new BitmapDrawable[numCellTypes];    private Bitmap background = null;    public MainView(Context context) {        super(context);        game = new MainGame(this);        //Loading resources        Resources resources = context.getResources();        try {            //Getting assets            backgroundRectangle = resources.getDrawable(R.drawable.background_rectangle);            TEXT_WHITE = resources.getColor(R.color.text_white);            TEXT_BLACK = resources.getColor(R.color.text_black);            this.setBackgroundColor(resources.getColor(R.color.background));            Typeface font = Typeface.createFromAsset(resources.getAssets(), "ClearSans-Bold.ttf");            paint.setTypeface(font);            paint.setAntiAlias(true);        } catch (Exception e) {            System.out.println("Error getting assets?");        }        gesture = new GestureDetector(context, new InputListener(this));        game.newGame();    }    @Override    protected void onDraw(Canvas canvas) {        canvas.drawBitmap(background, 0, 0, paint);        drawCells(canvas);    }    @Override    protected void onSizeChanged(int width, int height, int oldw, int oldh) {        super.onSizeChanged(width, height, oldw, oldh);        getLayout(width, height);        createBitmapCells();        createBackgroundBitmap(width, height);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        return gesture.onTouchEvent(event);    }    private void drawCells(Canvas canvas) {        paint.setTextSize(textSize);        paint.setTextAlign(Paint.Align.CENTER);        for (int i = 0; i < game.numSquaresX; i++) {            for (int j = 0; j < game.numSquaresY; j++) {                int sX = startX + gridWidth + (cellSize + gridWidth) * i;                int eX = sX + cellSize;                int sY = startY + gridWidth + (cellSize + gridWidth) * j;                int eY = sY + cellSize;                CellData currentCellData = game.grid.getCellContent(i, j);                if (currentCellData != null) {                    int value = currentCellData.getValue();                    int index = Utils.log2(value) >= numCellTypes ? numCellTypes - 1 : Utils.log2(value);                    bitmapCell[index].setBounds(sX, sY, eX, eY);                    bitmapCell[index].draw(canvas);                }            }        }    }    private void getLayout(int width, int height) {        cellSize = Math.min(width / (game.numSquaresX + 1), height / (game.numSquaresY + 3));        gridWidth = cellSize / 7;        int screenMiddleX = width / 2;        int screenMiddleY = height / 2;        paint.setTextAlign(Paint.Align.CENTER);        paint.setTextSize(cellSize);        textSize = cellSize * cellSize / Math.max(cellSize, paint.measureText("0000"));        cellTextSize = textSize;        //Grid Dimensions        double halfNumSquaresX = game.numSquaresX / 2d;        double halfNumSquaresY = game.numSquaresY / 2d;        startX = (int) (screenMiddleX - (cellSize + gridWidth) * halfNumSquaresX - gridWidth / 2);        endX = (int) (screenMiddleX + (cellSize + gridWidth) * halfNumSquaresX + gridWidth / 2);        startY = (int) (screenMiddleY - (cellSize + gridWidth) * halfNumSquaresY - gridWidth / 2);        endY = (int) (screenMiddleY + (cellSize + gridWidth) * halfNumSquaresY + gridWidth / 2);    }    private void createBitmapCells() {        Resources resources = getResources();        int[] cellRectangleIds = getCellRectangleIds();        paint.setTextAlign(Paint.Align.CENTER);        for (int i = 1; i < bitmapCell.length; i++) {            int value = (int) Math.pow(2, i);            paint.setTextSize(cellTextSize);            float tempTextSize = cellTextSize * cellSize * 0.9f / Math.max(cellSize * 0.9f, paint.measureText(String.valueOf(value)));            paint.setTextSize(tempTextSize);            Bitmap bitmap = Bitmap.createBitmap(cellSize, cellSize, Bitmap.Config.ARGB_8888);            Canvas canvas = new Canvas(bitmap);            drawDrawable(canvas, resources.getDrawable(cellRectangleIds[i]), 0, 0, cellSize, cellSize);            drawCellText(canvas, value, 0, 0);            bitmapCell[i] = new BitmapDrawable(resources, bitmap);        }    }    private int[] getCellRectangleIds() {        int[] cellRectangleIds = new int[numCellTypes];        cellRectangleIds[0] = R.drawable.cell_rectangle;        cellRectangleIds[1] = R.drawable.cell_rectangle_2;        cellRectangleIds[2] = R.drawable.cell_rectangle_4;        cellRectangleIds[3] = R.drawable.cell_rectangle_8;        cellRectangleIds[4] = R.drawable.cell_rectangle_16;        cellRectangleIds[5] = R.drawable.cell_rectangle_32;        cellRectangleIds[6] = R.drawable.cell_rectangle_64;        cellRectangleIds[7] = R.drawable.cell_rectangle_128;        cellRectangleIds[8] = R.drawable.cell_rectangle_256;        cellRectangleIds[9] = R.drawable.cell_rectangle_512;        cellRectangleIds[10] = R.drawable.cell_rectangle_1024;        cellRectangleIds[11] = R.drawable.cell_rectangle_2048;        cellRectangleIds[12] = R.drawable.cell_rectangle_4096;        return cellRectangleIds;    }    private void createBackgroundBitmap(int width, int height) {        background = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(background);        drawBackground(canvas);        drawBackgroundGrid(canvas);    }    private void drawBackground(Canvas canvas) {        drawDrawable(canvas, backgroundRectangle, startX, startY, endX, endY);    }    private void drawBackgroundGrid(Canvas canvas) {        Resources resources = getResources();        Drawable backgroundCell = resources.getDrawable(R.drawable.cell_rectangle);        for (int i = 0; i < game.numSquaresX; i++) {            for (int j = 0; j < game.numSquaresY; j++) {                int sX = startX + gridWidth + (cellSize + gridWidth) * i;                int eX = sX + cellSize;                int sY = startY + gridWidth + (cellSize + gridWidth) * j;                int eY = sY + cellSize;                drawDrawable(canvas, backgroundCell, sX, sY, eX, eY);            }        }    }    private void drawDrawable(Canvas canvas, Drawable draw, int startX, int startY, int endX, int endY) {        draw.setBounds(startX, startY, endX, endY);        draw.draw(canvas);    }    private void drawCellText(Canvas canvas, int value, int sX, int sY) {        int textShiftY = Utils.centerText(paint);        if (value >= 8) {            paint.setColor(TEXT_WHITE);        } else {            paint.setColor(TEXT_BLACK);        }        canvas.drawText("" + value, sX + cellSize / 2, sY + cellSize / 2 - textShiftY, paint);    }}

添加工具类Utils

工具类一般添加固定通用的方法，便于以后快速开发调用。
下面Utils中是对自定义MainView增加两种方法：一种是计算绘画字符串的基准线；一种是计算一个数是2的几次方

public class Utils {    public static int centerText(Paint paint) {        return (int) ((paint.descent() + paint.ascent()) / 2);    }    public static int log2(int n) {        if (n <= 0) throw new IllegalArgumentException();        return 31 - Integer.numberOfLeadingZeros(n);    }}

上面“计算一个数是2的几次方”还有其他方法：
(int) (Math.log10(n) / Math.log10(2))

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