从最简单的源代码开始,切勿眼高手低---(第一波)

从正式学习安卓到现在,差不多整整一年了,去年暑假,大约也就是6,7月份的样子,从图书馆借了好多书,安卓的,java的,假期里算是把李刚的<疯狂安卓讲义>完完整整的看完了,当时就只顾着看书,很少敲代码,也没做笔记,凭着脑子看,看完感觉收获还是挺大的,又看了mars老师的视频,没看完,大约看了第一季十几集差不多,终归停留在好像懂了的层面,也没做什么东西.

暑假过后,断断续续的学一点,发现java有点薄弱,毕竟没系统的学过,寒假之后到前段时间系统的把java过了一遍.到这时候我开始意识到做笔记和敲代码的重要性了,不做笔记,很快就会把当时明白的知识点遗忘掉,不敲代码,等真正用到的时候不知道怎么下手.

直到前段时间,自己亲手写了个小游戏,我才真正体会到学习的乐趣.还是要多实际的去操作才行.期末了,忙着各种考试,也有点迷茫接下来该怎么继续学习,感觉自己挺懂了,其实大多还是眼高手低.前天,碰巧在安卓巴士上找到一个别人分享的文件,里面是二十来个游戏的源代码,有点如获至宝的感觉啊.

于是按照从小到大的顺序排列了下来,打算现在开始加上暑假,挨着看一遍,自己实现一遍.

最小的一个便是下面这个.界面就是下面一个挡板,可控制左右移动,把下落的球弹上去.很常见的一个案例.看了一遍源代码,大体自己重写了一遍.收货真的很大,以后写完一个贴上来一个,也算是给代码做个笔记.

如果你也是新手,一定要多写.自己多写.亲手写.

下面是源码

public class PinBall extends Activity{

private int tableHeight;
private int tableWidth;
Random random = new Random();

//挡板大小和坐标
private final int racket_width = 70;
private final int racket_height = 20;
private int racketY;
private int racketX;

//球体大小,速度,坐标
private final int ballR = 12;
private int ballX;
private int ballY;
private int Vy = 3;
//生成一个比率(-0.5~0.5之间),用于产生随机方向
private double xyRate = random.nextDouble() - 0.5;
private int Vx = (int) (Vy * 2 * xyRate);

//游戏进行时标志
private boolean isLose = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
//全屏无标题
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
//设置游戏界面
final GameView game = new  GameView(this);
setContentView(game);
//获取桌面大小
WindowManager manager = getWindowManager();
Display display = manager.getDefaultDisplay();
tableHeight = display.getHeight();
tableWidth = display.getWidth();
//根据获取的桌面大小初始化坐标
initXY();

//重绘
final Handler handler = new Handler(){
public void handleMessage(Message message){
if(message.what == 0x123){
game.invalidate();
}
}
};

final Timer timer = new Timer();
timer.schedule(new TimerTask() {

@Override
public void run() {
//左右边框
if(ballX < 0 || (ballX + ballR > tableWidth)){
Vx = -Vx;
}
//超过下边界且未被球拍接住
if((ballY + ballR > racketY) && (ballX + ballR < racketX || ballX > racketX + racket_width)){
timer.cancel();
isLose = true;
}
//被球拍打回或者反弹时到达顶部
if(ballY < 0 || (ballY + ballR > racketY && ballX > racketX && ballX < racketX + racket_width )){
Vy = -Vy;
}
ballX += Vx;
ballY += Vy;
handler.sendEmptyMessage(0x123);
}
}, 0, 10);

//给游戏view加监听器
game.setOnTouchListener(new OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
int x = (int) event.getX();
int mid = tableWidth/2;
switch (x > mid ? 1 : 2) {
case 1:
if(racketX + racket_width < tableWidth){
racketX += 10;
}
break;
case 2:
if(racketX > 0){
racketX -= 10;
}
break;
}
game.invalidate();
return true;
}
});

}

private void initXY(){
racketY = tableHeight - 80;
racketX = random.nextInt(tableWidth);
ballX = random.nextInt(tableWidth);
ballY = random.nextInt(10) + 20;
}

class GameView extends View{

private static final float TEXT_SIZE = 40;

public GameView(Context context) {
super(context);
// TODO Auto-generated constructor stub
setFocusable(true);
}

@Override
protected void onDraw(Canvas canvas) {
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
//游戏结束
if (isLose) {
paint.setTextSize(TEXT_SIZE);
paint.setColor(Color.RED);
canvas.drawText("Game Over!", tableWidth/2 - paint.getTextSize()*2, tableHeight/2 - paint.getTextSize()/2, paint);
}
//游戏继续
else {
paint.setColor(Color.BLUE);
canvas.drawCircle(ballX, ballY, ballR, paint);
paint.setColor(Color.GREEN);
canvas.drawRect(racketX, racketY, racketX + racket_width, racketY + racket_height, paint);

}
}

}
}