Django动态展示Pyecharts图表数据的几种方法

Django 模板渲染

1. 新建一个 Django 项目

命令行中输入以下命令

1	`django-admin startproject pyecharts_django_demo`

创建一个应用程序

1	`python manage.py startapp demo`

创建完之后，在 Pycharm 中打开该项目，当然你也可以直接在 Pycharm 中创建

同时在pyecharts_django_demo/settings.py中注册应用程序INSTALLED_APPS中添加应用程序demo

在pyecharts_django_demo/urls.py中新增demo.urls

2. 新建项目 urls 文件

编辑demo/urls.py文件，没有就新建一个

from django.conf.urls import url
from . import views
  
urlpatterns = [
    url(r'^pie/$', views.ChartView.as_view(), name='demo'),
    url(r'^index/$', views.IndexView.as_view(), name='demo'),
]

3. 编写 Django 和 pyecharts 代码渲染图表

由于 json 数据类型的问题，无法将 pyecharts 中的 JSCode 类型的数据转换成 json 数据格式返回到前端页面中使用。

因此在使用前后端分离的情况下尽量避免使用 JSCode 进行画图。

将下列代码保存到demo/views.py中

from django.shortcuts import render
  
# Create your views here.
  
import json
from random import randrange
  
from django.http import HttpResponse
from rest_framework.views import APIView
  
from pyecharts.charts import Bar, Pie
from pyecharts.faker import Faker
from pyecharts import options as opts
  
  
# Create your views here.
def response_as_json(data):
    json_str = json.dumps(data)
    response = HttpResponse(
        json_str,
        content_type="application/json",
    )
    response["Access-Control-Allow-Origin"] = "*"
    return response
  
  
def json_response(data, code=200):
    data = {
        "code": code,
        "msg": "success",
        "data": data,
    }
    return response_as_json(data)
  
  
def json_error(error_string="error", code=500, **kwargs):
    data = {
        "code": code,
        "msg": error_string,
        "data": {}
    }
    data.update(kwargs)
    return response_as_json(data)
  
  
JsonResponse = json_response
JsonError = json_error
  
  
def pie_base() -> Pie:
    c = (
        Pie()
            .add("", [list(z) for z in zip(Faker.choose(), Faker.values())])
            .set_colors(["blue", "green", "yellow", "red", "pink", "orange", "purple"])
            .set_global_opts(title_opts=opts.TitleOpts(title="Pie-示例"))
            .set_series_opts(label_opts=opts.LabelOpts(formatter="{b}: {c}"))
            .dump_options_with_quotes()
    )
    return c
  
class ChartView(APIView):
    def get(self, request, *args, **kwargs):
        return JsonResponse(json.loads(pie_base()))
  
class IndexView(APIView):
    def get(self, request, *args, **kwargs):
        return HttpResponse(content=open("./templates/index.html").read())

在根目录下新建一个templates的文件夹,并在该文件夹下新建一个index.html文件

index.html

代码如下:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Awesome-pyecharts</title>
    <script src="https://cdn.bootcss.com/jquery/3.0.0/jquery.min.js"></script>
    <script type="text/javascript" src="https://assets.pyecharts.org/assets/echarts.min.js"></script>
  
</head>
<body>
<div id="pie" style="width:1000px; height:600px;"></div>
<script>
    var chart = echarts.init(document.getElementById('pie'), 'white', {renderer: 'canvas'});
  
    $(
        function () {
            fetchData(chart);
        }
    );
  
    function fetchData() {
        $.ajax({
            type: "GET",
            url: "http://127.0.0.1:8000/demo/pie",
            dataType: 'json',
            success: function (result) {
                chart.setOption(result.data);
            }
        });
    }
</script>
</body>
</html>

运行之后，在浏览器中打开，效果如下：

定时全量更新图表

前面讲的是一个静态数据的展示的方法，用 Pyecharts 和 Django 结合最主要是实现一种动态更新数据，增量更新数据等功能！

定时全量更新主要是前端主动向后端进行数据刷新，定时刷新的核心在于 HTML 的 setInterval 方法。

那么index.html代码就是下面这样的：

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Awesome-pyecharts</title>
    <script src="https://cdn.bootcss.com/jquery/3.0.0/jquery.min.js"></script>
    <script type="text/javascript" src="https://assets.pyecharts.org/assets/echarts.min.js"></script>
  
</head>
<body>
    <div id="bar" style="width:1600px; height:800px;"></div>
    <script>
        var chart = echarts.init(document.getElementById('bar'), 'white', {renderer: 'canvas'});
  
        $(
            function () {
                fetchData(chart);
                setInterval(fetchData, 100);
            }
        );
  
        function fetchData() {
            $.ajax({
                type: "GET",
                url: "http://127.0.0.1:8000/demo/bar",
                dataType: 'json',
                success: function (result) {
                    chart.setOption(result.data);
                }
            });
        }
    </script>
</body>
</html>

同时在demo/views.py中，增加并修改代码:

views.py

demo/urls.py中，增加如下代码：

运行之后，效果如下:

贴一张以前做的图(因为我懒)，效果和上面一样

定时增量更新图表

原理一样，先修改 index.html ，代码如下：

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Awesome-pyecharts</title>
    <script src="https://cdn.bootcss.com/jquery/3.0.0/jquery.min.js"></script>
    <script type="text/javascript" src="https://assets.pyecharts.org/assets/echarts.min.js"></script>
  
</head>
<body>
    <div id="bar" style="width:1600px; height:800px;"></div>
    <script>
        var chart = echarts.init(document.getElementById('bar'), 'white', {renderer: 'canvas'});
        var old_data = [];
        $(
            function () {
                fetchData(chart);
                setInterval(fetchData, 2000);
            }
        );
  
        function fetchData() {
            $.ajax({
                type: "GET",
                url: "http://127.0.0.1:8000/demo/line",
                dataType: "json",
                success: function (result) {
                    var options = result.data;
                    chart.setOption(options);
                    old_data = chart.getOption().series[0].data;
                }
            });
        }
  
        function getDynamicData() {
            $.ajax({
                type: "GET",
                url: "http://127.0.0.1:8000/demo/lineUpdate",
                dataType: 'json',
                success: function (result) {
                    var options = result.data;
                    old_data.push([options.name, options.value]);
                    chart.setOption({
                        series: [{
                            data: old_data
                        }]
                    });
                }
            });
        }
  
    </script>
</body>
</html>

细心的你应该可以发现，里面新增了两个请求地址demo/line,demo/lineUpdate

so，在urlpatterns中增加以下路径的匹配

1 2	`url(r'^line/$', views.ChartView.as_view(), name='demo'),` `url(r'^lineUpdate/$', views.ChartView.as_view(), name='demo'),`

最后在views.py中增加以下代码:

def line_base() -> Line:
    line = (
        Line()
            .add_xaxis(["{}".format(i) for i in range(10)])
            .add_yaxis(
            series_name="",
            y_axis=[randrange(50, 80) for _ in range(10)],
            is_smooth=True,
            label_opts=opts.LabelOpts(is_show=False),
        )
            .set_global_opts(
            title_opts=opts.TitleOpts(title="动态数据"),
            xaxis_opts=opts.AxisOpts(type_="value"),
            yaxis_opts=opts.AxisOpts(type_="value"),
        )
            .dump_options_with_quotes()
    )
    return line
  
class ChartView(APIView):
    def get(self, request, *args, **kwargs):
        return JsonResponse(json.loads(line_base())
cnt = 9
  
class ChartUpdateView(APIView):
    def get(self, request, *args, **kwargs):
        global cnt
        cnt = cnt + 1
        return JsonResponse({"name": cnt, "value": randrange(0, 100)})

运行并打开，效果如下：

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