Question

我想在MPAndroidChart库中新添加的时间序列图表中添加以下类型的数据（可以是1000以下任意数量的此类对）

Value :  50.0   at   1472112259
Value :  49.0   at   1472112294
Value :  50.0   at   1472112329
Value :  50.0   at   1472112360
Value :  50.0   at   1472112392

将从阵列中获取以下数据。现在，我想时间戳有些混乱。以下是完整的代码：https://gist.github.com/utkarshns/e1723dcc57022fcd392bc3b127b6c898

在我可以成功向图表添加值之后，UNIX时间戳将被解析为所需的时间格式。

目前，我遇到的问题是时间戳可能会被剪裁而且值会被覆盖，这会导致一个非常混乱的图形，其中包含非常奇怪的x轴值。

更新：截图： http://imgur.com/a/dGfmz

Answer 1

问题是Float值不能保持非常大的数字且仍然准确，因此您需要单独的List以及这些时间戳值。 # python ball_tracking.py --video ball_tracking_example.mp4 # python ball_tracking.py # import the necessary packages from collections import deque import numpy as np import argparse import imutils import cv2 # construct the argument parse and parse the arguments ap = argparse.ArgumentParser() ap.add_argument("-v", "--video", help="path to the (optional) video file") ap.add_argument("-b", "--buffer", type=int, default=64, help="max buffer size") args = vars(ap.parse_args()) # define the lower and upper boundaries of the "green" # ball in the HSV color space, then initialize the # list of tracked points greenLower = (29, 86, 6) greenUpper = (64, 255, 255) pts = deque(maxlen=args["buffer"]) # if a video path was not supplied, grab the reference # to the webcam if not args.get("video", False): camera = cv2.VideoCapture(0) # otherwise, grab a reference to the video file else: camera = cv2.VideoCapture(args["video"]) # keep looping while True: # grab the current frame (grabbed, frame) = camera.read() # if we are viewing a video and we did not grab a frame, # then we have reached the end of the video if args.get("video") and not grabbed: break # resize the frame, blur it, and convert it to the HSV # color space frame = imutils.resize(frame, width=600) # blurred = cv2.GaussianBlur(frame, (11, 11), 0) hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV) # construct a mask for the color "green", then perform # a series of dilations and erosions to remove any small # blobs left in the mask mask = cv2.inRange(hsv, greenLower, greenUpper) mask = cv2.erode(mask, None, iterations=2) mask = cv2.dilate(mask, None, iterations=2) # find contours in the mask and initialize the current # (x, y) center of the ball cnts = cv2.findContours(mask.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2] center = None # only proceed if at least one contour was found if len(cnts) > 0: # find the largest contour in the mask, then use # it to compute the minimum enclosing circle and # centroid c = max(cnts, key=cv2.contourArea) ((x, y), radius) = cv2.minEnclosingCircle(c) M = cv2.moments(c) center = (int(M["m10"] / M["m00"]), int(M["m01"] / M["m00"])) # only proceed if the radius meets a minimum size if radius > 10: # draw the circle and centroid on the frame, # then update the list of tracked points cv2.circle(frame, (int(x), int(y)), int(radius), (0, 255, 255), 2) cv2.circle(frame, center, 5, (0, 0, 255), -1) # update the points queue pts.appendleft(center) # loop over the set of tracked points for i in xrange(1, len(pts)): # if either of the tracked points are None, ignore # them if pts[i - 1] is None or pts[i] is None: continue # otherwise, compute the thickness of the line and # draw the connecting lines thickness = int(np.sqrt(args["buffer"] / float(i + 1)) * 2.5) cv2.line(frame, pts[i - 1], pts[i], (0, 0, 255), thickness) # show the frame to our screen cv2.imshow("Frame", frame) key = cv2.waitKey(1) & 0xFF # if the 'q' key is pressed, stop the loop if key == ord("q"): break # cleanup the camera and close any open windows camera.release() cv2.destroyAllWindows()应该没问题。距离是根据时间间隔。只需从开始日期到结束日期进行迭代，记录您拥有的时间戳数量，并根据您希望您的值具有的时间戳添加条目。

BigDecimal

你的ValueFormatter应该是这样的：

Long myValues[] = {1472112259L, 1472112294L, 1472112329L, 1472112360L, 1472112392L};// your values

   ArrayList<Entry> values = new ArrayList<>();// Entry List
   Long start = 1472112259L;//start
   Long end = 1472112392L;//end
   List<BigDecimal> mList = new ArrayList<>(); //Decimal list which holds timestamps
   int count = 0;

   for (Long i = start; i <= end; i++) {

       mList.add(new BigDecimal(i));
       if (myValues.equals(i)) {
           values.add(new Entry(count, 50));
       }
       count++;//always increment
   }

如果您有任何问题或某些事情不明确，我会很乐意提供帮助。

如何处理MPAndroidChart中的时间序列？

1 个答案: