Android SurfaceView游戏开发示例

 

当我们需要开发一个复杂游戏的时候，而且对程序的执行效率要求很高时，View类就不能满足需求了，这时必须用SurfaceView类进行开发。

例如，对速度要求很高的游戏时，View类就不能满足需求了，这时必须使用SurfaceView类进行开发。例如，对速度要求很高的游戏，可以使用双缓冲来显示。游戏中的背景、人物、动画等都需要绘制在一个画布(Canvas)上，而SurfaceView可以直接访问一个画布，SurfaceView 是提供给需要直接画像素而不是使用窗体部件的应用使用的。 每个Surface创建一个Canvas对象(但属性时常改变),用来管理View和Surface上的绘图操作。 

 

具体示例：

Activity

 

public class Activity01 extends Activity {

    GameSurfaceView gameView = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        gameView = new GameSurfaceView(this);
        setContentView(gameView);
    }
}

 

 

GameSurfaceView

 

public class GameSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Runnable{

    private Activity01 mActivity = null;

    private SurfaceHolder mHolder = null;
    private Thread mThread = null;;
    private boolean mLoop = false;

    private Canvas mCanvas = null;
    private Paint mPaint = null;
    private long drawStartTime = 0, drawCostTime = 0, drawTotalTime = 30;

    private float x, y;
    private int screenWidth = 480, screenHeight = 800;

    public GameSurfaceView(Context context) {
        super(context);

        mActivity = (Activity01)context;

        mHolder = this.getHolder();
        mHolder.addCallback(this);
        setFocusable(true);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        mPaint = new Paint();
        mPaint.setColor(Color.CYAN);
        mLoop = true;

        new Thread(this).start();
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        screenWidth = width;
        screenHeight = height;

        x = screenWidth / 2;
        y = screenHeight / 2;
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        mLoop = false;
    }

    @Override
    public void run() {
        while(mLoop){
            drawStartTime = SystemClock.uptimeMillis();

            synchronized (mHolder) {
                try {
                    mCanvas = mHolder.lockCanvas();
                    onDraw();       // repaint
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if(mCanvas != null){
                        mHolder.unlockCanvasAndPost(mCanvas);
                    }
                }
            }

            drawCostTime = SystemClock.uptimeMillis() - drawStartTime;
            Log.i("drawCostTime", "drawCostTime = " + drawCostTime);
            try {
                if(drawCostTime < drawTotalTime){
                    Thread.sleep(drawTotalTime - drawCostTime);     // sleep elapse time
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    private void onDraw(){
        if(mHolder == null && mPaint == null){
            return;
        }

        mPaint.setAntiAlias(true);
        mPaint.setAlpha(100);

        mPaint.setColor(Color.CYAN);    // paint background color
        mCanvas.drawRect(0, 0, screenWidth, screenHeight, mPaint);

        mPaint.setColor(Color.BLUE);    // paint foreground color
        mCanvas.drawCircle(x, y, 50, mPaint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        super.onTouchEvent(event);

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            this.x = event.getX();
            this.y = event.getY();
            break;

        case MotionEvent.ACTION_MOVE:
            this.x = event.getX();
            this.y = event.getY();
            break;

        case MotionEvent.ACTION_UP:
            this.x = event.getX();
            this.y = event.getY();
            break;

        default:
            this.x = event.getX();
            this.y = event.getY();
            break;
        }

        return true;    // true then event can be implemented again
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event){
        super.onKeyDown(keyCode, event);

        if(keyCode == KeyEvent.ACTION_DOWN){
            this.mActivity.finish();
        }

        return true;
    }
}

运行效果：

 

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