paint触摸轨迹监听，主要是三种而已，ACTION_DOWN，ACTION_MOVE，ACTION_UP

public boolean onTouchEvent(MotionEvent event){   int action = event.getAction();   float x = event.getX();   float y = event.getY();   switch(action){   case MotionEvent.ACTION_DOWN:    mPath.moveTo(x, y);    break;   case MotionEvent.ACTION_MOVE:    mPath.quadTo(mPosX, mPosY, x, y);    break;   case MotionEvent.ACTION_UP:    //mPath.reset();    break;   }   //记录当前触摸点得当前得坐标   mPosX = x;   mPosY = y;return true;}

但是触摸绘制轨迹有两种效果，一种是手指移动完毕，轨迹出现，那么设置在ACTION_UP中：在ACTION_UP中绘制cacheCanvas.drawPath(path, paint);

public boolean onTouchEvent(MotionEvent event) {        // TODO Auto-generated method stub        float x = event.getX();        float y = event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN : {                cur_x = x;                cur_y = y;                path.moveTo(cur_x, cur_y);                isMoving = true;                break;            }            case MotionEvent.ACTION_MOVE : {                if (!isMoving)                    break;                // 二次曲线方式绘制                path.quadTo(cur_x, cur_y, x, y);        //        cacheCanvas.drawPath(path, paint);                // 下面这个方法貌似跟上面一样                // path.lineTo(x, y);                cur_x = x;                cur_y = y;                break;            }            case MotionEvent.ACTION_UP : {                // 鼠标弹起保存最后状态                cacheCanvas.drawPath(path, paint);                path.reset();                isMoving = false;                break;            }        }

第二种是触摸的时候显示绘制轨迹，那么就在ACTION_MOVE中设置：cacheCanvas.drawPath(path, paint);

public boolean onTouchEvent(MotionEvent event) {        // TODO Auto-generated method stub        float x = event.getX();        float y = event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN : {                cur_x = x;                cur_y = y;                path.moveTo(cur_x, cur_y);                isMoving = true;                break;            }            case MotionEvent.ACTION_MOVE : {                if (!isMoving)                    break;                // 二次曲线方式绘制                path.quadTo(cur_x, cur_y, x, y);                cacheCanvas.drawPath(path, paint);                // 下面这个方法貌似跟上面一样                // path.lineTo(x, y);                cur_x = x;                cur_y = y;                break;            }            case MotionEvent.ACTION_UP : {                // 鼠标弹起保存最后状态        //        cacheCanvas.drawPath(path, paint);                path.reset();                isMoving = false;                break;            }        }