Android自定义View实现游戏摇杆键盘的方法示例

public class RemoteViewBg {private Bitmap bitmapBg;public RemoteViewBg(Bitmap bitmap) { bitmapBg = bitmap;}//背景的绘图函数public void draw(Canvas canvas, Paint paint, Rect src0 ,Rect dst0 ) { canvas.drawBitmap(bitmapBg, src0, dst0, paint);}}

 @Overridepublic boolean onTouchEvent(MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() ==  MotionEvent.ACTION_MOVE) { //   // 在范围外触摸  if (Math.sqrt(Math.pow((bigCircleX - (int) event.getX()), 2) + Math.pow((bigCircleY - (int) event.getY()), 2)) >= bigCircleR) {   double tempRad = getRad(bigCircleX, bigCircleY, event.getX(), event.getY());   getXY(bigCircleX, bigCircleY, bigCircleR, tempRad);  } else {//范围内触摸   smallCircleX = (int) event.getX();   smallCircleY = (int) event.getY();  } } else if (event.getAction() == MotionEvent.ACTION_UP) {  smallCircleX = bigCircleX;  smallCircleY = bigCircleY; } return true;}

/*** * 得到两点之间的弧度 */public float getRad(float px1, float py1, float px2, float py2) { float x = px2 - px1; float y = py1 - py2; //斜边的长 float z = (float) Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)); float cosAngle = x / z; float rad = (float) Math.acos(cosAngle); if (py2 < py1) {  rad = -rad; } return rad;}

public void draw() { try {  canvas = sfh.lockCanvas();  canvas.drawColor(getResources().getColor(R.color.ghostwhite)); // 指定图片绘制区域(左上角的四分之一)  Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());  // 指定图片在屏幕上显示的区域  Rect dst = new Rect(bigCircleX - bigCircleR, bigCircleY - bigCircleR, bigCircleX + bigCircleR, bigCircleY + bigCircleR);  // 绘制图片  remoteViewBg.draw(canvas, paint, src, dst);  paint.setColor(0x70ff0000);  //绘制摇杆  canvas.drawCircle(smallCircleX, smallCircleY, smallCircleR, paint); } catch (Exception e) {  // TODO: handle exception } finally {  try {   if (canvas != null)    sfh.unlockCanvasAndPost(canvas);  } catch (Exception e2) {   e2.printStackTrace();  } }}

 RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.dance_relative_layout); remoteSurfaceView = new RemoteSurfaceView(this); params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,  RelativeLayout.LayoutParams.MATCH_PARENT); remoteSurfaceView.setLayoutParams(params); relativeLayout.addView(remoteSurfaceView);

public class RemoteSurfaceView extends SurfaceView implements Callback, Runnable {private float scale = this.getResources().getDisplayMetrics().density;private Thread th;private SurfaceHolder sfh;private Canvas canvas;private Paint paint;private boolean flag;private int bigCircleX = 0;private int bigCircleY =0;private int bigCircleR = 0;//摇杆的X,Y坐标以及摇杆的半径private float smallCircleX = 0;private float smallCircleY = 0;private float smallCircleR = 0;private Bitmap bitmap;private RemoteViewBg remoteViewBg;public RemoteSurfaceView(Context context) { super(context); sfh = this.getHolder(); sfh.addCallback(this); paint = new Paint(); paint.setAntiAlias(true); setFocusable(true); setFocusableInTouchMode(true); setZOrderOnTop(true); getHolder().setFormat(PixelFormat.TRANSPARENT);}public void surfaceCreated(SurfaceHolder holder) { int width = getWidth(); int height = getHeight(); bigCircleX = width / 2; bigCircleY = height / 2; bigCircleR = width / 4; smallCircleX = width / 2; smallCircleY = height / 2; smallCircleR = width / 8; bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.fangxiang); remoteViewBg = new RemoteViewBg(bitmap); th = new Thread(this); flag = true; th.start();}/*** * 得到两点之间的弧度 */public float getRad(float px1, float py1, float px2, float py2) { float x = px2 - px1; float y = py1 - py2; //斜边的长 float z = (float) Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)); float cosAngle = x / z; float rad = (float) Math.acos(cosAngle); if (py2 < py1) {  rad = -rad; } return rad;}@Overridepublic boolean onTouchEvent(MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE) {  // 在范围外触摸  if (Math.sqrt(Math.pow((bigCircleX - (int) event.getX()), 2) + Math.pow((bigCircleY - (int) event.getY()), 2)) >= bigCircleR) {   double tempRad = getRad(bigCircleX, bigCircleY, event.getX(), event.getY());   getXY(bigCircleX, bigCircleY, bigCircleR, tempRad);  } else {//范围内触摸   smallCircleX = (int) event.getX();   smallCircleY = (int) event.getY();  } } else if (event.getAction() == MotionEvent.ACTION_UP) {  smallCircleX = bigCircleX;  smallCircleY = bigCircleY; } return true;}public void getXY(float x, float y, float R, double rad) { //获取圆周运动的X坐标 smallCircleX = (float) (R * Math.cos(rad)) + x; //获取圆周运动的Y坐标 smallCircleY = (float) (R * Math.sin(rad)) + y;}public void draw() { try {  canvas = sfh.lockCanvas();  canvas.drawColor(getResources().getColor(R.color.ghostwhite));  // 指定图片绘制区域(左上角的四分之一)  Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());  // 指定图片在屏幕上显示的区域  Rect dst = new Rect(bigCircleX - bigCircleR, bigCircleY - bigCircleR, bigCircleX + bigCircleR, bigCircleY + bigCircleR);  // 绘制图片  remoteViewBg.draw(canvas, paint, src, dst);  paint.setColor(0x70ff0000);  //绘制摇杆  canvas.drawCircle(smallCircleX, smallCircleY, smallCircleR, paint); } catch (Exception e) {  // TODO: handle exception } finally {  try {   if (canvas != null)    sfh.unlockCanvasAndPost(canvas);  } catch (Exception e2) {   e2.printStackTrace();  } }}public void run() { while (flag) {  draw();  try {   Thread.sleep(50);  } catch (Exception ex) {   ex.printStackTrace();  } }}public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {}public void surfaceDestroyed(SurfaceHolder holder) { flag = false;} }