javascript - D3 布局强制从折叠的子项开始

Question

这就是我正在处理的内容:

var data =

{
 name: "flare",
 children: [
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},
  {name: "analytics", children:[{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"},{name: "testera1"}]},

 ]
};

var width = 960,
    height = 500,
    root;

var force = d3.layout.force()
    .linkDistance(80)
    .charge(-120)
    .gravity(.05)
    .size([width, height])
    .on("tick", tick);

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

var link = svg.selectAll(".link"),
    node = svg.selectAll(".node");



  root = data;
 
 update();
  


function update() {

  var nodes = flatten(root),
      links = d3.layout.tree().links(nodes);

  // Restart the force layout.
  force
      .nodes(nodes)
      .links(links)
      .start();

  // Update links.
  link = link.data(links, function(d) { return d.target.id; });

  link.exit().remove();

  link.enter().insert("line", ".node")
      .attr("class", "link");

  // Update nodes.
  node = node.data(nodes, function(d) { return d.id; });

  node.exit().remove();

  var nodeEnter = node.enter().append("g")
      .attr("class", "node")
      .on("click", click)
      .call(force.drag);

  nodeEnter.append("circle")
      .attr("r", function(d) { return Math.sqrt(d.size) / 10 || 4.5; });

  nodeEnter.append("text")
      .attr("dy", ".35em")
      .text(function(d) { return d.name; });

  node.select("circle")
      .style("fill", color);

}

function tick() {
  link.attr("x1", function(d) { return d.source.x; })
      .attr("y1", function(d) { return d.source.y; })
      .attr("x2", function(d) { return d.target.x; })
      .attr("y2", function(d) { return d.target.y; });

  node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
}

function color(d) {
  return d._children ? "#3182bd" // collapsed package
      : d.children ? "#c6dbef" // expanded package
      : "#fd8d3c"; // leaf node
}

// Toggle children on click.
function click(d) {
  if (d3.event.defaultPrevented) return; // ignore drag
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update();
}

// Returns a list of all nodes under the root.
function flatten(root) {
  var nodes = [], i = 0;

  function recurse(node) {
    if (node.children) node.children.forEach(recurse);
    if (!node.id) node.id = ++i;
    nodes.push(node);
  }

  recurse(root);
  return nodes;
}

.node circle {
  cursor: pointer;
  stroke: #3182bd;
  stroke-width: 1.5px;
}

.node text {
  font: 10px sans-serif;
  pointer-events: none;
  text-anchor: middle;
}

line.link {
  fill: none;
  stroke: #9ecae1;
  stroke-width: 1.5px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<script src="//d3js.org/d3.v3.min.js"></script>

基本上，一切正常，除了这将从所有子项展开开始，但我需要它加载折叠的子项。我尝试过运行

 function collapse(d) {
                        if (d.children) {
                          d._children = d.children;
                          d._children.forEach(collapse);
                          d.children = null;
                        }

但这并没有帮助。我尝试用以下方法折叠它们:

function collapseAll(){
    root.children.forEach(collapse);
    collapse(root);
    update(root);
}

也没有用。

Answer 1

您的collapse函数的实现似乎是正确的。然而，在您的 collapseAll 函数中，您为根节点的每个子节点以及根节点本身调用 collapse ，从而在树上递归两次。

这是一个working fiddle .

请注意，在折叠节点之前必须调用 update 函数一次，以便绘制它们。