Javascript D3.JS中的可折叠图：多个根点

我希望使用d3js创建一个可折叠图，但我想添加许多根点（下面示例中的顶级_1和顶级_2）

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这个例子不起作用。如何在同一个图中创建多个独立的可折叠树？

层次图只能有一个根；有人要求d3允许多根树，但到目前为止，所有的请求都被拒绝了。要创建具有多个根的树，我们可以创建两个独立的树，或者通过隐藏根节点来假装拥有两个独立的树

您的数据结构无效（最好使用代码格式化程序对缩进进行标准化，确保不会在这样复杂的数据结构中出错），因此我添加了一个根节点并编辑了现有节点，以正确表示层次结构

隐藏根节点的最简单方法是使用CSS。为此，我根据每个节点、链接和文本项在树中的深度（例如，

level-0

，

level-1

，等等），为每个节点、链接和文本项指定了一个类

level-n

。从根目录隐藏根目录和链接就是将class

level-0

元素设置为

opacity:0

使用中的代码，我们可以找到

更新

功能代码的相关部分，并添加到新的css类中：

  // add the class to the whole `g` element
  var nodeEnter = node.enter().append("g")
    .attr("class", function(d){
      return 'node level-'+d.depth; // add the node depth
    })
    .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
    .on("click", click);

对链接执行相同的操作：

  // each link has two nodes, the source and the target; we want to
  // label our links with the source node (the parent node)
  link.enter().insert("path", "g")
      .attr("class", function(d){
        return 'link level-' + d.source.depth})
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      });

在CSS页面中，将CSS类

级别0

设置为不透明度0：

  .level-0 {
    opacity: 0;
  }

因为我们现在在左边有一个空的空间，缺少的节点所在的位置，所以整个图表可以移到左边。您可能需要相应地更改树维度

代码现在如下所示：

var treeData = [{
  name: "null",
  children: [{
    "name": "Top Level_1",
    "parent": "null",
    "children": [{
      "name": "Level 2: A",
      "parent": "Top Level_1",
      "children": [{
        "name": "Son of A",
        "parent": "Level 2: A"
      }, {
        "name": "Daughter of A",
        "parent": "Level 2: A"
      }]
    },
    {
      "name": "Level 2: B",
      "parent": "Top Level"
    }],
  }, {
    "name": "Top Level_2",
    "parent": "null",
    "children": [
    {
      "name": "Level 2_2: A",
      "parent": "Top Level_2",
      "children": [
      {
        "name": "Son of A_2",
        "parent": "Level 2_2: A"
      },
      {
        "name": "Daughter of A_2",
        "parent": "Level 2_2: A"
      }]
    },
    {
      "name": "Level 2_2: B",
      "parent": "Top Level_2"
    }]
  }]
}];

// ************** Generate the tree diagram  *****************
var margin = {
    top: 20,
    right: 120,
    bottom: 20,
    left: 120
  },
  width = 960 - margin.right - margin.left,
  height = 500 - margin.top - margin.bottom;

var i = 0,
  duration = 750,
  root;

var tree = d3.layout.tree()
  .size([height, width]);

var diagonal = d3.svg.diagonal()
  .projection(function(d) {
    return [d.y, d.x];
  });

var svg = d3.select("body").append("svg")
  .attr("width", width + margin.right + margin.left)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
  .attr("transform", "translate(" + (margin.left - 120) + "," + margin.top + ")");

root = treeData[0];
root.x0 = height / 2;
root.y0 = 0;

update(root);

d3.select(self.frameElement).style("height", "500px");

function update(source) {

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse(),
    links = tree.links(nodes);

  // Normalize for fixed-depth.
  nodes.forEach(function(d) {
    d.y = d.depth * 120;
  });

  // Update the nodes…
  var node = svg.selectAll("g.node")
    .data(nodes, function(d) {
      return d.id || (d.id = ++i);
    });

  // Enter any new nodes at the parent's previous position.
  var nodeEnter = node.enter().append("g")
    .attr("class", function(d) {
      return 'node level-' + d.depth;
    })
    .attr("transform", function(d) {
      return "translate(" + source.y0 + "," + source.x0 + ")";
    })
    .on("click", click);

  nodeEnter.append("circle")
    .attr("r", 1e-6)
    .style("fill", function(d) {
      return d._children ? "lightsteelblue" : "#fff";
    });

  nodeEnter.append("text")
    .attr('class', function(d) {
      return 'node-text level-' + d.level
    })
    .attr("x", function(d) {
      return d.children || d._children ? -13 : 13;
    })
    .attr("dy", ".35em")
    .attr("text-anchor", function(d) {
      return d.children || d._children ? "end" : "start";
    })
    .text(function(d) {
      return d.name;
    })
    .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.
  var nodeUpdate = node.transition()
    .duration(duration)
    .attr("transform", function(d) {
      return "translate(" + d.y + "," + d.x + ")";
    });

  nodeUpdate.select("circle")
    .attr("r", 10)
    .style("fill", function(d) {
      return d._children ? "lightsteelblue" : "#fff";
    });

  nodeUpdate.select("text")
    .style("fill-opacity", 1);

  // Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit().transition()
    .duration(duration)
    .attr("transform", function(d) {
      return "translate(" + source.y + "," + source.x + ")";
    })
    .remove();

  nodeExit.select("circle")
    .attr("r", 1e-6);

  nodeExit.select("text")
    .style("fill-opacity", 1e-6);

  // Update the links…
  var link = svg.selectAll("path.link")
    .data(links, function(d) {
      return d.target.id;
    });

  // Enter any new links at the parent's previous position.
  link.enter().insert("path", "g")
    .attr("class", function(d) {
      return 'link level-' + d.source.depth
    })
    .attr("d", function(d) {
      var o = {
        x: source.x0,
        y: source.y0
      };
      return diagonal({
        source: o,
        target: o
      });
    });

  // Transition links to their new position.
  link.transition()
    .duration(duration)
    .attr("d", diagonal);

  // Transition exiting nodes to the parent's new position.
  link.exit().transition()
    .duration(duration)
    .attr("d", function(d) {
      var o = {
        x: source.x,
        y: source.y
      };
      return diagonal({
        source: o,
        target: o
      });
    })
    .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children on click.
function click(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update(d);
}

---

请发布您迄今为止尝试过的代码，并阅读上的建议。好的，对不起，我认为它很清楚。我将更新question@ialarmedalien完成。

var treeData = [{
  name: "null",
  children: [{
    "name": "Top Level_1",
    "parent": "null",
    "children": [{
      "name": "Level 2: A",
      "parent": "Top Level_1",
      "children": [{
        "name": "Son of A",
        "parent": "Level 2: A"
      }, {
        "name": "Daughter of A",
        "parent": "Level 2: A"
      }]
    },
    {
      "name": "Level 2: B",
      "parent": "Top Level"
    }],
  }, {
    "name": "Top Level_2",
    "parent": "null",
    "children": [
    {
      "name": "Level 2_2: A",
      "parent": "Top Level_2",
      "children": [
      {
        "name": "Son of A_2",
        "parent": "Level 2_2: A"
      },
      {
        "name": "Daughter of A_2",
        "parent": "Level 2_2: A"
      }]
    },
    {
      "name": "Level 2_2: B",
      "parent": "Top Level_2"
    }]
  }]
}];

// ************** Generate the tree diagram  *****************
var margin = {
    top: 20,
    right: 120,
    bottom: 20,
    left: 120
  },
  width = 960 - margin.right - margin.left,
  height = 500 - margin.top - margin.bottom;

var i = 0,
  duration = 750,
  root;

var tree = d3.layout.tree()
  .size([height, width]);

var diagonal = d3.svg.diagonal()
  .projection(function(d) {
    return [d.y, d.x];
  });

var svg = d3.select("body").append("svg")
  .attr("width", width + margin.right + margin.left)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
  .attr("transform", "translate(" + (margin.left - 120) + "," + margin.top + ")");

root = treeData[0];
root.x0 = height / 2;
root.y0 = 0;

update(root);

d3.select(self.frameElement).style("height", "500px");

function update(source) {

  // Compute the new tree layout.
  var nodes = tree.nodes(root).reverse(),
    links = tree.links(nodes);

  // Normalize for fixed-depth.
  nodes.forEach(function(d) {
    d.y = d.depth * 120;
  });

  // Update the nodes…
  var node = svg.selectAll("g.node")
    .data(nodes, function(d) {
      return d.id || (d.id = ++i);
    });

  // Enter any new nodes at the parent's previous position.
  var nodeEnter = node.enter().append("g")
    .attr("class", function(d) {
      return 'node level-' + d.depth;
    })
    .attr("transform", function(d) {
      return "translate(" + source.y0 + "," + source.x0 + ")";
    })
    .on("click", click);

  nodeEnter.append("circle")
    .attr("r", 1e-6)
    .style("fill", function(d) {
      return d._children ? "lightsteelblue" : "#fff";
    });

  nodeEnter.append("text")
    .attr('class', function(d) {
      return 'node-text level-' + d.level
    })
    .attr("x", function(d) {
      return d.children || d._children ? -13 : 13;
    })
    .attr("dy", ".35em")
    .attr("text-anchor", function(d) {
      return d.children || d._children ? "end" : "start";
    })
    .text(function(d) {
      return d.name;
    })
    .style("fill-opacity", 1e-6);

  // Transition nodes to their new position.
  var nodeUpdate = node.transition()
    .duration(duration)
    .attr("transform", function(d) {
      return "translate(" + d.y + "," + d.x + ")";
    });

  nodeUpdate.select("circle")
    .attr("r", 10)
    .style("fill", function(d) {
      return d._children ? "lightsteelblue" : "#fff";
    });

  nodeUpdate.select("text")
    .style("fill-opacity", 1);

  // Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit().transition()
    .duration(duration)
    .attr("transform", function(d) {
      return "translate(" + source.y + "," + source.x + ")";
    })
    .remove();

  nodeExit.select("circle")
    .attr("r", 1e-6);

  nodeExit.select("text")
    .style("fill-opacity", 1e-6);

  // Update the links…
  var link = svg.selectAll("path.link")
    .data(links, function(d) {
      return d.target.id;
    });

  // Enter any new links at the parent's previous position.
  link.enter().insert("path", "g")
    .attr("class", function(d) {
      return 'link level-' + d.source.depth
    })
    .attr("d", function(d) {
      var o = {
        x: source.x0,
        y: source.y0
      };
      return diagonal({
        source: o,
        target: o
      });
    });

  // Transition links to their new position.
  link.transition()
    .duration(duration)
    .attr("d", diagonal);

  // Transition exiting nodes to the parent's new position.
  link.exit().transition()
    .duration(duration)
    .attr("d", function(d) {
      var o = {
        x: source.x,
        y: source.y
      };
      return diagonal({
        source: o,
        target: o
      });
    })
    .remove();

  // Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children on click.
function click(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update(d);
}