Android遊戲開發中對象移動的例子

轉載 ： http://cwq.yfjhh.com/2009/05/android.html

該遊戲對象移動，以view的背景作動畫，假設開始的位置是父View座標的(0,0)
遊戲角色view的事件監聽應該在父view中監聽。
同時注意，AnimationDrawable.start()不能在Activity.onCreate事件未執行完就調用,
但可以用在比如點擊按紐後就調用等。

public class Dog extends View implements OnKeyListener, Runnable {
       
        // 左右移動對應不同的背景動畫,用這個記下當前的背景動畫
        private AnimationDrawable nowAnim;
        // 左移動對應的背景動畫
        private AnimationDrawable animLeft;
        // 右移動對應的背景動畫
        private AnimationDrawable animRight;
        private View parent;
       
        // 記下view的座標位置，用於移動後重畫該地區。該座標是相對於父View的。
        // 同時要注意，如果父View是有padding的，要算上，因為是以父Vew的左上方點為原點的
        // padding最好為每次位移量的正倍數。l,t,r,b為即時的座標位置,step為每次位移量
        private int l=0,t=0,r=22,b=20,step=3;

        public Dog(Context context, View parent) {
                super(context);
                // TODO Auto-generated constructor stub
                this.parent = parent;
                // 記下父容器,即父View
               
                l += parent.getPaddingLeft(); t += parent.getPaddingTop();
                r += parent.getPaddingRight(); b += parent.getPaddingBottom();
                // 如果父view有padding,要算上，因為view的座標是以父view的左上方為原點的
               
                // 產生左和右移動對應的背景動畫,其實只是一個png,有對象移動時是的幾個圖片,將其分拆成移動的動畫
                animLeft = AndroidUtils.animationFromSplitImage(
                                context, R.drawable.woniu, 22, 20, 200);
                // 只需一個移動方向的png就行了,該animationFromSplitImage函數是將映像水來翻轉。
                animRight = AndroidUtils.animationFromSplitImage(
                                AndroidUtils.imageFlipHorizintal(context, R.drawable.woniu), 22, 20, 200);
               
                setAnimationDrawable( animRight );
                //this.setOnKeyListener( this );
               
        }
       
        private void setAnimationDrawable(AnimationDrawable anim) {
                if( nowAnim != null ) {
                        nowAnim.stop();
                        // 必須要先stop才行，不然會影響到下一個動畫的情況
                        nowAnim = null;
                }
                nowAnim = anim;
                this.setBackgroundDrawable(nowAnim);
        }
       
        // 返回當前的動畫，用於在其它地方控制停止等。
        public AnimationDrawable getBgAnimationDrawable() {
                return nowAnim;
        }
       
        public boolean onKey(View v, int keyCode, KeyEvent event) {
                // TODO Auto-generated method stub
                if( event.getAction() == KeyEvent.ACTION_DOWN )
                {
                        switch (keyCode)
                        {
                        case KeyEvent.KEYCODE_DPAD_LEFT: {
                                if( getLeft()>parent.getPaddingLeft() ) {
                                        // 左或右位移量，是相對當前View的座標
                                        offsetLeftAndRight(-1*step);
                                        // 記下當前的座標值，用於在父view中重畫經過的地區。
                                        l -= step;
                                }
                                if( animLeft != nowAnim ) {
                                        setAnimationDrawable( animLeft );
                                        nowAnim.start();
                                }
                                break ;
                        }
                        case KeyEvent.KEYCODE_DPAD_RIGHT: {
                                if( getRight()<(parent.getWidth() - parent.getPaddingRight()) ) {
                                        offsetLeftAndRight(step);
                                        r += step;
                                }
                                if( animRight != nowAnim ) {
                                        setAnimationDrawable( animRight );
                                        nowAnim.start();
                                }
                                break ;
                        }
                        case KeyEvent.KEYCODE_DPAD_UP: {
                                if( getTop()>parent.getPaddingTop() ) {
                                        offsetTopAndBottom(-1*step);
                                        t -= step;
                                }
                                break ;
                        }
                        case KeyEvent.KEYCODE_DPAD_DOWN: {
                                if( getBottom()<(parent.getHeight() - parent.getPaddingBottom()) ) {
                                        offsetTopAndBottom(step);
                                        b += step;
                                }
                                break ;
                        }
                        case KeyEvent.KEYCODE_DPAD_CENTER: {
                                break ;
                        }
                        default: {}
                        }
                        repaint();
                }
                return true;
        }

        public void run() {
                // TODO Auto-generated method stub
                // 每次位移後，都重畫位移前的地區的內容
                parent.invalidate(l,t,r,b);
        }
       
        public void repaint() {
                this.post(this);
        }
}