Android树形控件绘制方法

前言

作为一个开发者，日常会接触到很多优秀的软件，其实，或多或少会有这样的想法，我能不能开发一个自己软件，甚至办公软件都希望是Markdown的文本，为何用office？我常常想自己做一个IDE什么的。但是，很多只是想了一下就过了，一直没有实现.
我接触思维导图软件已经很久的了，开始是使用微软的思维导图软件，接着XMind，后来使用了MindMaple Lite。感觉很好用的。也想过如何去实现一个思维导图的软件，加之我特别注意软件的快捷键，我选取软件常常是，看快捷如何，快捷键差的就不要了。基于自己的实践使用思维导图。前一个月我就在github上实现了一个树形图的Android控件，这个其实是我想实现思维导图的开始。实现后，才发现并没有多大的障碍。下面我就说说我如何打造一个树形控件的。先上效果：

效果1

效果2

实现

一步一步可夺城。将自己要实现的东西肢解，那些实现得了的？那些未知的？

思路步骤概要

整个结构分为：树形，节点；对于Android的结构有：模型（树形，节点），View；

实现树形的节点node 的Model；
实现树形Model;
实现View的绘制：1.添加View；2.确定Nodes的位置；3.连线Node；

详细步骤

看到思路步骤概要后，相信我们的思路已经很清晰了。感觉是不是很simple，是的，实现也如此。到这里了，我就开始编码。但是为了教会大家，我提几个疑问给大家：

树的遍历如何实现？（可以google，如果你学过数据结构当然simple了）
节点和节点这间使用什么关联？（next）
如何确定Node的位置？位置有什么规律？（？？）
如何实现两个View之间的连线？（？？）
……

其实问题还真的有一点。但是这些都不能妨碍我们的步伐，还是写好已知的代码吧。

代码

1.树的节点。主要是一些需要的数据。父节点，值，子节点，是否对焦（对于将来用的），在树形的层……

package com.owant.drawtreeview.model;

import java.util.linkedList;



public class TreeNode {
 
 public TreeNode parentNode;

 
 public T value;

 
 public linkedList> childNodes;

 
 public boolean focus;

 
 public int floor;

 public TreeNode(T value) {
  this.value = value;
  this.childNodes = new linkedList>();

//  this.focus = false;
//  this.parentNode = null;
 }

 public TreeNode getParentNode() {
  return parentNode;
 }

 public void setParentNode(TreeNode parentNode) {
  this.parentNode = parentNode;
 }

 public T getValue() {
  return value;
 }

 public void setValue(T value) {
  this.value = value;
 }

 public linkedList> getChildNodes() {
  return childNodes;
 }

 public void setChildNodes(linkedList> childNodes) {
  this.childNodes = childNodes;
 }

 public boolean isFocus() {
  return focus;
 }

 public void setFocus(boolean focus) {
  this.focus = focus;
 }

 public int getFloor() {
  return floor;
 }

 public void setFloor(int floor) {
  this.floor = floor;
 }
}

2.树形。根节点，添加节点，遍历，上一个节点，下一个节点，基于点拆分的上下节点集合。

package com.owant.drawtreeview.model;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.linkedList;
import java.util.Stack;



public class Tree {

 
 public TreeNode rootNode;

 public Tree(TreeNode rootNode) {
  this.rootNode = rootNode;
 }

 
 public void addNode(TreeNode start, TreeNode... nodes) {
  int index = 1;
  TreeNode temp = start;
  if (temp.getParentNode() != null) {
   index = temp.getParentNode().floor;
  }

  for (TreeNode t : nodes) {
   t.setParentNode(start);
   t.setFloor(index);
   start.getChildNodes().add(t);
  }
 }

 public boolean remvoeNode(TreeNode starNode, TreeNode deleteNote) {
  boolean rm = false;
  int size = starNode.getChildNodes().size();
  if (size > 0) {
   rm = starNode.getChildNodes().remove(deleteNote);
  }
  return rm;
 }

 public TreeNode getRootNode() {
  return rootNode;
 }

 public void setRootNode(TreeNode rootNode) {
  this.rootNode = rootNode;
 }

 
 public TreeNode getLowNode(TreeNode midPreNode) {
  TreeNode find = null;
  TreeNode parentNode = midPreNode.getParentNode();

  if (parentNode != null && parentNode.getChildNodes().size() >= 2) {
   Deque> queue = new ArrayDeque<>();
   TreeNode rootNode = parentNode;
   queue.add(rootNode);
   boolean up = false;
   while (!queue.isEmpty()) {

    rootNode = (TreeNode) queue.poll();
    if (up) {
     if (rootNode.getFloor() == midPreNode.getFloor()) {
      find = rootNode;
     }
     break;
    }

    //到了该元素
    if (rootNode == midPreNode) up = true;
    linkedList> childNodes = rootNode.getChildNodes();
    if (childNodes.size() > 0) {
     for (TreeNode item : childNodes) {
      queue.add(item);
     }
    }
   }
  }
  return find;
 }

 public TreeNode getPreNode(TreeNode midPreNode) {

  TreeNode parentNode = midPreNode.getParentNode();
  TreeNode find = null;

  if (parentNode != null && parentNode.getChildNodes().size() > 0) {

   Deque> queue = new ArrayDeque<>();
   TreeNode rootNode = parentNode;
   queue.add(rootNode);

   while (!queue.isEmpty()) {
    rootNode = (TreeNode) queue.poll();
    //到了该元素
    if (rootNode == midPreNode) {
     //返回之前的值
     break;
    }

    find = rootNode;
    linkedList> childNodes = rootNode.getChildNodes();
    if (childNodes.size() > 0) {
     for (TreeNode item : childNodes) {
      queue.add(item);
     }
    }
   }

   if (find != null && find.getFloor() != midPreNode.getFloor()) {
    find = null;
   }
  }
  return find;
 }

 public ArrayList> getAllLowNodes(TreeNode addNode) {
  ArrayList> array = new ArrayList<>();
  TreeNode parentNode = addNode.getParentNode();
  while (parentNode != null) {
   TreeNode lowNode = getLowNode(parentNode);
   while (lowNode != null) {
    array.add(lowNode);
    lowNode = getLowNode(lowNode);
   }
   parentNode = parentNode.getParentNode();
  }
  return array;
 }

 public ArrayList> getAllPreNodes(TreeNode addNode) {
  ArrayList> array = new ArrayList<>();
  TreeNode parentNode = addNode.getParentNode();
  while (parentNode != null) {
   TreeNode lowNode = getPreNode(parentNode);
   while (lowNode != null) {
    array.add(lowNode);
    lowNode = getPreNode(lowNode);
   }
   parentNode = parentNode.getParentNode();
  }
  return array;
 }

 public linkedList> getNodeChildNodes(TreeNode node) {
  return node.getChildNodes();
 }

 public void printTree() {
  Stack> stack = new Stack<>();
  TreeNode rootNode = getRootNode();
  stack.add(rootNode);
  while (!stack.isEmpty()) {
   TreeNode pop = stack.pop();
   System.out.println(pop.getValue().toString());
   linkedList> childNodes = pop.getChildNodes();
   for (TreeNode item : childNodes) {
    stack.add(item);
   }
  }
 }

 public void printTree2() {
  Deque> queue = new ArrayDeque<>();
  TreeNode rootNode = getRootNode();
  queue.add(rootNode);
  while (!queue.isEmpty()) {
   rootNode = (TreeNode) queue.poll();
   System.out.println(rootNode.getValue().toString());

   linkedList> childNodes = rootNode.getChildNodes();
   if (childNodes.size() > 0) {
    for (TreeNode item : childNodes) {
     queue.add(item);
    }
   }
  }

 }


}

3.测试模型 当我们实现了模型后，要写一些列子来测试模型是否正确，进行打印，遍历等测试，这是很重要的。对于树形的node的上一个node和下一个node的理解等。

4.树形的View

package com.owant.drawtreeview.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;

import com.owant.drawtreeview.R;
import com.owant.drawtreeview.model.Tree;
import com.owant.drawtreeview.model.TreeNode;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.linkedList;



public class SuperTreeView extends ViewGroup {

  
  private int mDx;
  private int mDy;
  private int mWith;
  private int mHeight;
  private Context mContext;
  private Tree mTree;
  private ArrayList mNodesViews;

  public SuperTreeView(Context context) {
    this(context, null, 0);
  }

  public SuperTreeView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }

  public SuperTreeView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    mContext = context;
    mNodesViews = new ArrayList<>();
    mContext = context;

    mDx = dp2px(mContext, 26);
    mDy = dp2px(mContext, 22);
  }

  
  private void onAddNodeViews() {
    if (mTree != null) {
      TreeNode rootNode = mTree.getRootNode();
      Deque> deque = new ArrayDeque<>();
      deque.add(rootNode);
      while (!deque.isEmpty()) {
 TreeNode poll = deque.poll();
 NodeView nodeView = new NodeView(mContext);
 nodeView.setTreeNode(poll);
 ViewGroup.LayoutParams lp = new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
 nodeView.setLayoutParams(lp);

 this.addView(nodeView);
 mNodesViews.add(nodeView);

 linkedList> childNodes = poll.getChildNodes();
 for (TreeNode ch : childNodes) {
   deque.push(ch);
 }
      }
    }
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    final int size = getChildCount();
    for (int i = 0; i < size; i++) {
      measureChild(getChildAt(i), widthMeasureSpec, heightMeasureSpec);
    }
  }

  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    mHeight = getMeasuredHeight();
    mWith = getMeasuredWidth();

    if (mTree != null) {
      NodeView rootView = findTreeNodeView(mTree.getRootNode());
      if (rootView != null) {
 //root的位置
 rootTreeViewLayout(rootView);
 //标准位置
 for (NodeView nv : mNodesViews) {
   standardTreeChildLayout(nv);
 }

 //基于父子的移动
 for (NodeView nv : mNodesViews) {
   fatherChildCorrect(nv);
 }

      }
    }

  }

  private void rootTreeViewLayout(NodeView rootView) {
    int lr = mDy;
    int tr = mHeight / 2 - rootView.getMeasuredHeight() / 2;
    int rr = lr + rootView.getMeasuredWidth();
    int br = tr + rootView.getMeasuredHeight();
    rootView.layout(lr, tr, rr, br);
  }

  @Override
  protected void dispatchDraw(Canvas canvas) {
    if (mTree != null) {
      drawTreeLine(canvas, mTree.getRootNode());
    }
    super.dispatchDraw(canvas);
  }

  
  private void standardTreeChildLayout(NodeView rootView) {
    TreeNode treeNode = rootView.getTreeNode();
    if (treeNode != null) {
      //所有的子节点
      linkedList> childNodes = treeNode.getChildNodes();
      int size = childNodes.size();
      int mid = size / 2;
      int r = size % 2;

      //基线
      //    b
      //  a-------
      //    c
      //
      int left = rootView.getRight() + mDx;
      int top = rootView.getTop() + rootView.getMeasuredHeight() / 2;

      int right = 0;
      int bottom = 0;

      if (size == 0) {
 return;
      } else if (size == 1) {
 NodeView midChildNodeView = findTreeNodeView(childNodes.get(0));

 top = top - midChildNodeView.getMeasuredHeight() / 2;
 right = left + midChildNodeView.getMeasuredWidth();
 bottom = top + midChildNodeView.getMeasuredHeight();
 midChildNodeView.layout(left, top, right, bottom);
      } else {

 int topLeft = left;
 int topTop = top;
 int topRight = 0;
 int topBottom = 0;

 int bottomLeft = left;
 int bottomTop = top;
 int bottomRight = 0;
 int bottomBottom = 0;

 if (r == 0) {//偶数
   for (int i = mid - 1; i >= 0; i--) {
     NodeView topView = findTreeNodeView(childNodes.get(i));
     NodeView bottomView = findTreeNodeView(childNodes.get(size - i - 1));


     if (i == mid - 1) {
topTop = topTop - mDy / 2 - topView.getMeasuredHeight();
topRight = topLeft + topView.getMeasuredWidth();
topBottom = topTop + topView.getMeasuredHeight();

bottomTop = bottomTop + mDy / 2;
bottomRight = bottomLeft + bottomView.getMeasuredWidth();
bottomBottom = bottomTop + bottomView.getMeasuredHeight();
     } else {
topTop = topTop - mDy - topView.getMeasuredHeight();
topRight = topLeft + topView.getMeasuredWidth();
topBottom = topTop + topView.getMeasuredHeight();

bottomTop = bottomTop + mDy;
bottomRight = bottomLeft + bottomView.getMeasuredWidth();
bottomBottom = bottomTop + bottomView.getMeasuredHeight();
     }

     topView.layout(topLeft, topTop, topRight, topBottom);
     bottomView.layout(bottomLeft, bottomTop, bottomRight, bottomBottom);

     bottomTop = bottomView.getBottom();
   }

 } else {
   NodeView midView = findTreeNodeView(childNodes.get(mid));
   midView.layout(left, top - midView.getMeasuredHeight() / 2, left + midView.getMeasuredWidth(),
top - midView.getMeasuredHeight() / 2 + midView.getMeasuredHeight());

   topTop = midView.getTop();
   bottomTop = midView.getBottom();

   for (int i = mid - 1; i >= 0; i--) {
     NodeView topView = findTreeNodeView(childNodes.get(i));
     NodeView bottomView = findTreeNodeView(childNodes.get(size - i - 1));

     topTop = topTop - mDy - topView.getMeasuredHeight();
     topRight = topLeft + topView.getMeasuredWidth();
     topBottom = topTop + topView.getMeasuredHeight();

     bottomTop = bottomTop + mDy;
     bottomRight = bottomLeft + bottomView.getMeasuredWidth();
     bottomBottom = bottomTop + bottomView.getMeasuredHeight();

     topView.layout(topLeft, topTop, topRight, topBottom);
     bottomView.layout(bottomLeft, bottomTop, bottomRight, bottomBottom);
     bottomTop = bottomView.getBottom();
   }
 }
      }
    }

  }

  
  private void moveNodeLayout(NodeView rootView, int dy) {

    Deque> queue = new ArrayDeque<>();
    TreeNode rootNode = rootView.getTreeNode();
    queue.add(rootNode);
    while (!queue.isEmpty()) {
      rootNode = (TreeNode) queue.poll();
      rootView = findTreeNodeView(rootNode);
      int l = rootView.getLeft();
      int t = rootView.getTop() + dy;
      rootView.layout(l, t, l + rootView.getMeasuredWidth(), t + rootView.getMeasuredHeight());

      linkedList> childNodes = rootNode.getChildNodes();
      for (TreeNode item : childNodes) {
 queue.add(item);
      }
    }
  }

  private void fatherChildCorrect(NodeView nv) {
    int count = nv.getTreeNode().getChildNodes().size();

    if (nv.getParent() != null && count >= 2) {
      TreeNode tn = nv.getTreeNode().getChildNodes().get(0);
      TreeNode bn = nv.getTreeNode().getChildNodes().get(count - 1);
      Log.i("see fc", nv.getTreeNode().getValue() + ":" + tn.getValue() + "," + bn.getValue());

      int topDr = nv.getTop() - findTreeNodeView(tn).getBottom() + mDy;
      int bnDr = findTreeNodeView(bn).getTop() - nv.getBottom() + mDy;
      //上移动
      ArrayList> allLowNodes = mTree.getAllLowNodes(bn);
      ArrayList> allPreNodes = mTree.getAllPreNodes(tn);

      for (TreeNode low : allLowNodes) {
 NodeView view = findTreeNodeView(low);
 moveNodeLayout(view, bnDr);
      }

      for (TreeNode pre : allPreNodes) {
 NodeView view = findTreeNodeView(pre);
 moveNodeLayout(view, -topDr);
      }
    }
  }


  
  private void drawTreeLine(Canvas canvas, TreeNode root) {
    NodeView fatherView = findTreeNodeView(root);
    if (fatherView != null) {
      linkedList> childNodes = root.getChildNodes();
      for (TreeNode node : childNodes) {
 drawLineToView(canvas, fatherView, findTreeNodeView(node));
 drawTreeLine(canvas, node);
      }
    }
  }

  
  private void drawLineToView(Canvas canvas, View from, View to) {

    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setStyle(Paint.Style.STROKE);

    float width = 2f;

    paint.setStrokeWidth(dp2px(mContext, width));
    paint.setColor(mContext.getResources().getColor(R.color.chelsea_cucumber));

    int top = from.getTop();
    int formY = top + from.getMeasuredHeight() / 2;
    int formX = from.getRight();

    int top1 = to.getTop();
    int toY = top1 + to.getMeasuredHeight() / 2;
    int toX = to.getLeft();

    Path path = new Path();
    path.moveTo(formX, formY);
    path.quadTo(toX - dp2px(mContext, 15), toY, toX, toY);

    canvas.drawPath(path, paint);
  }

  private NodeView findTreeNodeView(TreeNode node) {
    NodeView v = null;
    for (NodeView view : mNodesViews) {
      if (view.getTreeNode() == node) {
 v = view;
 continue;
      }
    }
    return v;
  }

  public int dp2px(Context context, float dpVal) {
    int result = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpVal, context.getResources()
 .getDisplayMetrics());
    return result;
  }

  public void setTree(Tree tree) {
    this.mTree = tree;
    onAddNodeViews();
  }

  public Tree getTree() {
    return mTree;
  }
}

粘贴代码后发现，没有什么好说了，对于读者来说，应该是一脸懵逼的。毕竟，那个位置是如何确定的呀，view和view的连线呀…… 对于整个View来说这是最难的，我也是探索了好久才得出结论的。首先，对于一个只有两层的树形来说，如图：

PQRS是基于F来计算的，之后分布。之后我就得到的方法如下：


  private void standardTreeChildLayout(NodeView rootView) {
    TreeNode treeNode = rootView.getTreeNode();
    if (treeNode != null) {
      //所有的子节点
      linkedList> childNodes = treeNode.getChildNodes();
      int size = childNodes.size();
      int mid = size / 2;
      int r = size % 2;

      //基线
      //    b
      //  a-------
      //    c
      //
      int left = rootView.getRight() + mDx;
      int top = rootView.getTop() + rootView.getMeasuredHeight() / 2;

      int right = 0;
      int bottom = 0;

      if (size == 0) {
 return;
      } else if (size == 1) {
 NodeView midChildNodeView = findTreeNodeView(childNodes.get(0));

 top = top - midChildNodeView.getMeasuredHeight() / 2;
 right = left + midChildNodeView.getMeasuredWidth();
 bottom = top + midChildNodeView.getMeasuredHeight();
 midChildNodeView.layout(left, top, right, bottom);
      } else {

 int topLeft = left;
 int topTop = top;
 int topRight = 0;
 int topBottom = 0;

 int bottomLeft = left;
 int bottomTop = top;
 int bottomRight = 0;
 int bottomBottom = 0;

 if (r == 0) {//偶数
   for (int i = mid - 1; i >= 0; i--) {
     NodeView topView = findTreeNodeView(childNodes.get(i));
     NodeView bottomView = findTreeNodeView(childNodes.get(size - i - 1));


     if (i == mid - 1) {
topTop = topTop - mDy / 2 - topView.getMeasuredHeight();
topRight = topLeft + topView.getMeasuredWidth();
topBottom = topTop + topView.getMeasuredHeight();

bottomTop = bottomTop + mDy / 2;
bottomRight = bottomLeft + bottomView.getMeasuredWidth();
bottomBottom = bottomTop + bottomView.getMeasuredHeight();
     } else {
topTop = topTop - mDy - topView.getMeasuredHeight();
topRight = topLeft + topView.getMeasuredWidth();
topBottom = topTop + topView.getMeasuredHeight();

bottomTop = bottomTop + mDy;
bottomRight = bottomLeft + bottomView.getMeasuredWidth();
bottomBottom = bottomTop + bottomView.getMeasuredHeight();
     }

     topView.layout(topLeft, topTop, topRight, topBottom);
     bottomView.layout(bottomLeft, bottomTop, bottomRight, bottomBottom);

     bottomTop = bottomView.getBottom();
   }

 } else {
   NodeView midView = findTreeNodeView(childNodes.get(mid));
   midView.layout(left, top - midView.getMeasuredHeight() / 2, left + midView.getMeasuredWidth(),
top - midView.getMeasuredHeight() / 2 + midView.getMeasuredHeight());

   topTop = midView.getTop();
   bottomTop = midView.getBottom();

   for (int i = mid - 1; i >= 0; i--) {
     NodeView topView = findTreeNodeView(childNodes.get(i));
     NodeView bottomView = findTreeNodeView(childNodes.get(size - i - 1));

     topTop = topTop - mDy - topView.getMeasuredHeight();
     topRight = topLeft + topView.getMeasuredWidth();
     topBottom = topTop + topView.getMeasuredHeight();

     bottomTop = bottomTop + mDy;
     bottomRight = bottomLeft + bottomView.getMeasuredWidth();
     bottomBottom = bottomTop + bottomView.getMeasuredHeight();

     topView.layout(topLeft, topTop, topRight, topBottom);
     bottomView.layout(bottomLeft, bottomTop, bottomRight, bottomBottom);
     bottomTop = bottomView.getBottom();
   }
 }
      }
    }

  }

之后等到的View情况如下:

说明我们还需要纠正。下面是纠正的探索，我精简一下结构如下情况：

发现：

B需要在E的上面；
D需要在I的下面；

就是EI要撑开ID的位置。之后我们可以先写这个算法，发现基本可以了。但是还是有问题，同层的还是会重合，只有我们又进行同层的纠正。发现好像解决了，其实还是不行，测试还是发现问题，对于单伸长还有问题，之后又是修改…………

最后发现……这里就不说了，就是自己要探索啦。

总结

最后我才发现了那个完善的纠正算法，就是代码了的。大家可以在我的github中找到我之前的TreeView中的那个位置算法探索。欢迎大家支持：https://github.com/owant/TreeView

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。

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