d3饼图不会重新显示

Question

I've got a pie chart and it will only draw once. I got it from Mike Bostock's pie chart example . I'm new to D3 and I can't figure out why it won't redraw. I saw this post about redrawing a bar chart, but for some reason that technique doesn't work on my pie chart. I'm sure I'm doing something wrong.

var width = 960,
    height = 500,
    radius = Math.min(width, height) / 2;

var arc = d3.svg.arc()
    .outerRadius(radius - 10)
    .innerRadius(0);

var pie = d3.layout.pie()
    .sort(null)
    .value(function(d) { return d.percent; });

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
  .append("g")
    .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");

function drawChart(error, data) {
  console.log("here");

  data.forEach(function(d) {
    d.percent = +d.percent;
  });

  var g = svg.selectAll(".arc")
      .data(pie(data))
      .enter()
      .append("g")
      .attr("class", "arc");

  g.append("path")
      .attr("d", arc)
      .style("fill", function(d) { 
    console.log("inside path"); 
    return d.data.color;
  });

  g.append("text")
      .attr("transform", function(d) { console.log("inside transform", d);return "translate(" + arc.centroid(d) + ")"; })
      .attr("dy", ".35em")
      .style("text-anchor", "middle")
      .text(function(d) { return d.data.color; });

}

drawChart(undefined, [{"color": "green", "percent": 50}, {"color": "red", "percent": 50}]);

setTimeout(function () {
  drawChart(undefined, [{"color": "green", "percent": 75}, {"color": "red", "percent": 25}]);
}, 1000)

here's the jsbin .

Answer 1

Problem 1:

You are adding the d attribute to the DOM g which is wrong.

<g class="arc" d="M-240,2.939152317953648e-14A240,240 0 0,1 -4.408728476930471e-14,-240L0,0Z">
      <path d="M-9.188564877424678e-14,240A240,240 0 1,1 1.6907553595872533e-13,-240L0,0Z" style="fill: red;">
</path>
      <text transform="translate(-120,-9.188564877424678e-14)" dy=".35em" style="text-anchor: middle;">red</text>
</g>

d attribute is only for path not for g.

So this line is incorrect

g.transition().duration(750).attrTween("d", arcTween); // redraw the arcs

Problem 2:

Your update function is incorrect(same reason problem 1)

function update (data) {
    console.log("here", data);
    var value = this.value;
    g = g.data(pie(data)); // compute the new angles
    g.transition().duration(750).attrTween("d", arcTween); // redraw the arcs
  };

In my opinion you should call your drawChart function again for update. with an exception that you remove old g group like this.

svg.selectAll(".arc").remove();

The advantage is that we are using the same code for create and update (DRY). So your timeout function becomes like thsi

setTimeout(function () {
  drawChart(undefined, [{"color": "green", "percent": 75}, {"color": "red", "percent": 25}]);
}, 2000);

Full working code here

Hope this helps!