public class BezierGestureTrackView extends View {

    private Bitmap mBufferBitmap;
    private Canvas mBufferCanvas;

    public BezierGestureTrackView(Context context) {
        super(context);
    }
    PointF pointF;

    Paint paint;
    Paint paint2;

    Path p,path ;

    @ColorInt public static final int YELLOW      = 0xFFFFFF00;
    @ColorInt
    public static final int CYAN        = 0xFF00FFFF;
    public static final int c1        = 0xEF8A97;
    public static final int c2        = 0xFBD2A8;

    public BezierGestureTrackView(Context context, AttributeSet attrs) {
        super(context, attrs);
        paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);//設定畫筆的填充模式
        paint.setStrokeJoin(Paint.Join.ROUND);//設定畫筆圖形接觸時筆跡的形狀
        paint.setStrokeCap(Paint.Cap.ROUND);//設定畫筆離開畫板時筆跡的形狀
        paint.setStrokeWidth(8);//設定畫筆粗細  6
        paint.setAntiAlias(true);//設定抗鋸齒
        paint.setColor(Color.WHITE);
        initPaint();
       // BitmapFactory.decodeResource(getResources(), R.drawable.hbbg);
    }


    //新建兩個SparseArray<Path>用來儲存我們畫出的Path物件,具體為什麼之後會解釋
    //mActivePointers用來儲存當前正在畫的Path
    SparseArray<Path> mActivePointers = new SparseArray<>();
    //truePointers用來儲存所有的Path，在onDraw()方法裡面我們也是繪製這裡的所有Path
    SparseArray<Path> truePointers = new SparseArray<>();

    //儲存單個點
    private int i=0;
    private float[] a= new float[1000];

//重寫onTouchEvent()方法
    @Override
    public boolean onTouchEvent(MotionEvent event) {

        //獲取當前DOWN或者UP的是手指的index
        int curPointerIndex = event.getActionIndex();
        //通過index獲得當前手指的id
        int curPointerId = event.getPointerId(curPointerIndex);
      //獲取當前正在發生的事件
        int actionMasked = event.getActionMasked();

        switch (actionMasked) {
        //不管是第一個還是第N個手指落下，都執行以下方法：
            case MotionEvent.ACTION_DOWN:


            case MotionEvent.ACTION_POINTER_DOWN:
            //新建一個PointF物件用來儲存點的座標
                pointF = new PointF();
                pointF.x = event.getX(curPointerIndex);
                pointF.y = event.getY(curPointerIndex);
                //每當有手指下落時，都新建一個Path，並移動到手指落下的點
                Path p = new Path();
                p.moveTo(pointF.x, pointF.y);
                //將新建的path新增到mActivePointers中
                mActivePointers.append(curPointerId, p);


                //儲存單個點位置

                if (i<998){
                    a[i++]=event.getX(curPointerIndex);
                    a[i++]=event.getY(curPointerIndex);
                }


                break;

            case MotionEvent.ACTION_MOVE:
            //當有手指移動時，遍歷mActivePointers，注意這裡遍歷的條件並不是mActivePointers.size(),而是event.getPointerCount()
            //也就是隻監控當前所有正在滑動的手指數，另外在MotionEvent.ACTION_UP事件中，抬起的手指已經從mActivePointers中刪除了
                for (int size = event.getPointerCount(), i = 0; i < size; i++) {
                //獲取mActivePointers中的每一個Path
                    path = mActivePointers.get(event.getPointerId(i));
                    if (path != null) {
                    //更新每一個Path將得到的點連線
                        path.lineTo(event.getX(i), event.getY(i));

                    }
                }

                break;
            case MotionEvent.ACTION_UP:


            case MotionEvent.ACTION_POINTER_UP:
            //當手指抬起時，代表已經繪製完畢，取得抬起的手指繪製圖線例項，傳入truePointers讓Drow()繪製
             path = mActivePointers.get(curPointerId);
                truePointers.append(truePointers.size(), path);
            //從mActivePointers中將抬起的手指刪除
                mActivePointers.remove(curPointerId);
                break;

        }
        //重繪
        invalidate();
        return true;
    }

    private void initBuffer(){
        mBufferBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
        mBufferCanvas = new Canvas(mBufferBitmap);
    }




    @Override
    protected void onDraw(Canvas canvas) {
         //canvas.drawColor(Color.BLACK);


//            Bitmap srcBitmap= BitmapFactory.decodeResource(getResources(), R.drawable.hbbg);
//            canvas.drawBitmap(srcBitmap,0f,0f,null);





        //遍歷mActivePointers，因為只有當手指抬起時Path才被加入truePointers,此時truePointers裡面還沒有儲存當前正在繪製的圖線
        //如果沒有遍歷mActivePointers，則圖線不會即時顯示，只有在抬起手指的瞬間，圖線才會一起顯示
                for (int size = mActivePointers.size(), i = 0; i < size; i++) {
                  Path path = mActivePointers.valueAt(i);
                  canvas.drawPath(path, paint);
        }
        //遍歷truePointers，這裡儲存的是當前正在畫的圖線
        for (int size = truePointers.size(), i = 0; i < size; i++) {
             path = truePointers.valueAt(i);
            //繪製truePointers裡的所有Path
            canvas.drawPath(path, paint);
        }

        if (pointF!=null){
            //canvas.drawPoint(pointF.x, pointF.y,paint2);
            canvas.drawPoints(a, paint2);


            for (int j = 0; j < a.length; j++) {
                Log.e("TAG","a:"+a[i]+"a的長度："+a.length);
            }
        }

    }
//    public void clean(){
////        Canvas canvas = sh.lockCanvas();
////
////
////        if(canvas!=null){
////            Paint paint = new Paint();
////            paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
////            canvas.drawPaint(paint);
//////canvas.drawColor(Color.BLUE);
////        }
//        Log.e("BezierGestureTrackView","CLEAN");
//    }

    public void clear() {


        if (mBufferBitmap != null) {
            if (mActivePointers!=null){
                mActivePointers.clear();
            }
            if (truePointers != null) {
                truePointers.clear();
            }

            mBufferBitmap.eraseColor(Color.TRANSPARENT);
            invalidate();

        }

    }


    private void initPaint() {
        paint2 = new Paint();
        //LinearGradient lg=new LinearGradient(0,0,100,100,Color.RED,Color.BLUE, Shader.TileMode.MIRROR); //引數一為漸變起初點座標x位
        LinearGradient lg=new LinearGradient(0,0,100,100,CYAN,YELLOW, Shader.TileMode.MIRROR); //引數一為漸變起初點座標x位
        paint2.setStyle(Paint.Style.STROKE);//設定畫筆的填充模式
        paint2.setStrokeJoin(Paint.Join.ROUND);//設定畫筆圖形接觸時筆跡的形狀
        paint2.setStrokeCap(Paint.Cap.ROUND);//設定畫筆離開畫板時筆跡的形狀
        paint2.setStrokeWidth(45);//設定畫筆粗細 50
        paint2.setAntiAlias(true);//設定抗鋸齒
        paint2.setColor(Color.WHITE);//設定抗鋸齒
        paint2.setShader(lg);
    }
}