LZ最近接手公司一个项目，需要写一个圆形的旋转菜单，并且支持菜单之间的移动换位，本来以为这种demo应该网上是很多的，想不到度娘也是帮不了我，，空有旋转功能但是却不能换位置，所以LZ就只能靠自己摸索了。
最终LZ参考了网上的部分代码，重写了一个自定义的view终于实现了这个看似很吊，却没有实际意义的功能。在此贡献出来给广大码农们共享。
话不多说，先上代码：
自定义view类：
public class RoundSpinView extends View {private Paint mPaint = new Paint();private PaintFlagsDrawFilter pfd;private int startMenu; //菜单的第一张图片的资源id// stone列表private BigStone[] mStones;// 数目private static final int STONE_COUNT = 3;// 圆心坐标private int mPointX = 0, mPointY = 0;// 半径private int mRadius = 0;// 每两个点间隔的角度private int mDegreeDelta;private int menuRadius; // 菜单的半径private int mCur = -1; // 正在被移动的menu;private boolean[] quadrantTouched; //对每个象限触摸情况的记录// Touch detectionprivate GestureDetector mGestureDetector;private onRoundSpinViewListener mListener; //自定义事件监听器private final static int TO_ROTATE_BUTTON = 0; //旋转按钮；private Handler handler = new Handler(){public void handleMessage(Message msg) {switch (msg.what) {case TO_ROTATE_BUTTON:float velocity = Float.parseFloat(msg.obj.toString());rotateButtons(velocity/75);velocity /= 1.0666F;new Thread(new FlingRunnable(velocity)).start();break;default:break;}};};public interface onRoundSpinViewListener{public void onSingleTapUp(int position); //监听每个菜单的单击事件}public RoundSpinView(Context context,AttributeSet attrs) {super(context,attrs);if(attrs!=null){TypedArray a = getContext().obtainStyledAttributes(attrs,R.styleable.RoundSpinView);startMenu = a.getResourceId(R.styleable.RoundSpinView_menuStart, 0);}pfd = new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG); mPaint.setColor(Color.WHITE);mPaint.setStrokeWidth(2);mPaint.setAntiAlias(true); //消除锯齿mPaint.setStyle(Paint.Style.STROKE); //绘制空心圆 PathEffect effects = new DashPathEffect(new float[]{5,5,5,5},1);mPaint.setPathEffect(effects);quadrantTouched = new boolean[] { false, false, false, false, false };mGestureDetector = new GestureDetector(getContext(),new MyGestureListener());setupStones();}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {// TODO Auto-generated method stubsuper.onMeasure(widthMeasureSpec, heightMeasureSpec);mPointX = this.getMeasuredWidth()/2;mPointY = this.getMeasuredHeight()/2;//初始化半径和菜单半径mRadius = mPointX-mPointX/5;menuRadius = (int)(mPointX/5.5);computeCoordinates();}/** * 初始化每个点 */private void setupStones() {mStones = new BigStone[STONE_COUNT];BigStone stone;int angle = 270;mDegreeDelta = 360 / STONE_COUNT;for (int index = 0; index < STONE_COUNT; index++) {stone = new BigStone();if (angle >= 360) {angle -= 360;}else if(angle < 0){angle += 360;}stone.angle = angle;stone.bitmap = BitmapFactory.decodeResource(getResources(),startMenu + index);angle += mDegreeDelta;mStones[index] = stone;}}/** * 重新计算每个点的角度 */private void resetStonesAngle(float x, float y) {int angle = computeCurrentAngle(x, y);Log.d("RoundSpinView", "angle:" + angle);for (int index = 0; index < STONE_COUNT; index++) {mStones[index].angle = angle;angle += mDegreeDelta;}}/** * 计算每个点的坐标 */private void computeCoordinates() {BigStone stone;for (int index = 0; index < STONE_COUNT; index++) {stone = mStones[index];stone.x = mPointX+ (float) (mRadius * Math.cos(Math.toRadians(stone.angle)));stone.y = mPointY+ (float) (mRadius * Math.sin(Math.toRadians(stone.angle)));}}/** * 计算某点的角度 * * @param x * @param y * @return */private int computeCurrentAngle(float x, float y) {float distance = (float) Math.sqrt(((x – mPointX) * (x – mPointX) + (y – mPointY)* (y – mPointY)));int degree = (int) (Math.acos((x – mPointX) / distance) * 180 / Math.PI);if (y < mPointY) {degree = -degree;}Log.d("RoundSpinView", "x:" + x + ",y:" + y + ",degree:" + degree);return degree;}private double startAngle;@Overridepublic boolean dispatchTouchEvent(MotionEvent event) {// resetStonesAngle(event.getX(), event.getY());// computeCoordinates();// invalidate();int x, y;if (event.getAction() == MotionEvent.ACTION_DOWN) {x = (int) event.getX();y = (int) event.getY();mCur = getInCircle(x, y);if (mCur == -1) {startAngle = computeCurrentAngle(x, y);}} else if (event.getAction() == MotionEvent.ACTION_MOVE) {x = (int) event.getX();y = (int) event.getY();if (mCur != -1) {mStones[mCur].x = x;mStones[mCur].y = y;invalidate();} else {double currentAngle = computeCurrentAngle(x, y);rotateButtons(startAngle – currentAngle);startAngle = currentAngle;}} else if (event.getAction() == MotionEvent.ACTION_UP) {x = (int) event.getX();y = (int) event.getY();if (mCur != -1) {computeCoordinates();int cur = getInCircle(x, y);if (cur != mCur && cur != -1) {int angle = mStones[mCur].angle;mStones[mCur].angle = mStones[cur].angle;mStones[cur].angle = angle;}computeCoordinates();invalidate();mCur = -1;}}// set the touched quadrant to truequadrantTouched[getQuadrant(event.getX() – mPointX,mPointY – event.getY())] = true;mGestureDetector.onTouchEvent(event);return true;}private class MyGestureListener extends SimpleOnGestureListener {@Overridepublic boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,float velocityY) {// get the quadrant of the start and the end of the flingint q1 = getQuadrant(e1.getX() – mPointX, mPointY – e1.getY());int q2 = getQuadrant(e2.getX() – mPointX, mPointY – e2.getY());// the inversed rotationsif ((q1 == 2 && q2 == 2 && Math.abs(velocityX) < Math.abs(velocityY))|| (q1 == 3 && q2 == 3)|| (q1 == 1 && q2 == 3)|| (q1 == 4 && q2 == 4 && Math.abs(velocityX) > Math.abs(velocityY))|| ((q1 == 2 && q2 == 3) || (q1 == 3 && q2 == 2))|| ((q1 == 3 && q2 == 4) || (q1 == 4 && q2 == 3))|| (q1 == 2 && q2 == 4 && quadrantTouched[3])|| (q1 == 4 && q2 == 2 && quadrantTouched[3])) {// CircleLayout.this.post(new FlingRunnable(-1// * (velocityX + velocityY)));new Thread(new FlingRunnable(velocityX+velocityY)).start();} else {// the normal rotation// CircleLayout.this// .post(new FlingRunnable(velocityX + velocityY));new Thread(new FlingRunnable(-(velocityX+velocityY))).start();}return true;}@Overridepublic boolean onSingleTapUp(MotionEvent e) {int cur = getInCircle((int)e.getX(),(int)e.getY());if(cur!=-1){if(mListener!=null){mListener.onSingleTapUp(cur);}//Toast.makeText(getContext(), "position:"+cur, 0).show();return true;}return false;}}private class FlingRunnable implements Runnable{private float velocity;public FlingRunnable(float velocity){this.velocity = velocity;}@Overridepublic void run() {// TODO Auto-generated method stubif(Math.abs(velocity)>=200){Message message = Message.obtain();message.what = TO_ROTATE_BUTTON;message.obj = velocity;handler.sendMessage(message);}}}/** * @return The selected quadrant. */private static int getQuadrant(double x, double y) {if (x >= 0) {return y >= 0 ? 1 : 4;} else {}return y >= 0 ? 2 : 3;}/* * 旋转菜单按钮 */private void rotateButtons(double degree) {for (int i = 0; i < STONE_COUNT; i++) {mStones[i].angle -= degree;if (mStones[i].angle < 0) {mStones[i].angle += 360;}else if(mStones[i].angle >=360){mStones[i].angle -= 360;}}computeCoordinates();invalidate();}@Overridepublic void onDraw(Canvas canvas) {//画一个白色的圆环canvas.drawCircle(mPointX, mPointY, mRadius, mPaint);//将每个菜单画出来for (int index = 0; index < STONE_COUNT; index++) {if (!mStones[index].isVisible)continue;drawInCenter(canvas, mStones[index].bitmap, mStones[index].x,mStones[index].y);}}/** * 把中心点放到中心处 * * @param canvas * @param bitmap * @param left * @param top */private void drawInCenter(Canvas canvas, Bitmap bitmap, float left,float top) {Rect dst = new Rect();dst.left = (int) (left – menuRadius);dst.right = (int) (left + menuRadius);dst.top = (int) (top – menuRadius);dst.bottom = (int) (top + menuRadius);canvas.setDrawFilter(pfd); canvas.drawBitmap(bitmap, null, dst, mPaint);}private int getInCircle(int x, int y) {for (int i = 0; i < STONE_COUNT; i++) {BigStone stone = mStones[i];int mx = (int) stone.x;int my = (int) stone.y;if (((x – mx) * (x – mx) + (y – my) * (y – my)) < menuRadius* menuRadius) {return i;}}return -1;}public void setOnRoundSpinViewListener(onRoundSpinViewListener listener){this.mListener = listener;}class BigStone {// 图片Bitmap bitmap;// 角度int angle;// x坐标float x;// y坐标float y;// 是否可见boolean isVisible = true;}}layout文件代码：<LinearLayout xmlns:android=""xmlns:app=""android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"><com.example.roundspinviewdemo.view.RoundSpinViewandroid:id="@+id/rsv_test"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_gravity="center"android:background="@drawable/menubkground"app:menuStart="@drawable/menu1" /></LinearLayout>注意：必须加上这一条 ：xmlns:app=""如果没法忘记他，就不要忘记好了。真正的忘记，是不需要努力的。
