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<T> {
public TreeNode<T> parentNode;
public T value;
public LinkedList<TreeNode<T>> childNodes;
public boolean focus;
public int floor;
public TreeNode(T value) {
this.value = value;
this.childNodes = new LinkedList<TreeNode<T>>();
// this.focus = false;
// this.parentNode = null;
}
public TreeNode<T> getParentNode() {
return parentNode;
}
public void setParentNode(TreeNode<T> parentNode) {
this.parentNode = parentNode;
}
public T getValue() {
return value;
}
public void setValue(T value) {
this.value = value;
}
public LinkedList<TreeNode<T>> getChildNodes() {
return childNodes;
}
public void setChildNodes(LinkedList<TreeNode<T>> 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<T> {
public TreeNode<T> rootNode;
public Tree(TreeNode<T> rootNode) {
this.rootNode = rootNode;
}
public void addNode(TreeNode<T> start, TreeNode<T>... nodes) {
int index = 1;
TreeNode<T> temp = start;
if (temp.getParentNode() != null) {
index = temp.getParentNode().floor;
}
for (TreeNode<T> t : nodes) {
t.setParentNode(start);
t.setFloor(index);
start.getChildNodes().add(t);
}
}
public boolean remvoeNode(TreeNode<T> starNode, TreeNode<T> deleteNote) {
boolean rm = false;
int size = starNode.getChildNodes().size();
if (size > 0) {
rm = starNode.getChildNodes().remove(deleteNote);
}
return rm;
}
public TreeNode<T> getRootNode() {
return rootNode;
}
public void setRootNode(TreeNode<T> rootNode) {
this.rootNode = rootNode;
}
public TreeNode<T> getLowNode(TreeNode<T> midPreNode) {
TreeNode<T> find = null;
TreeNode<T> parentNode = midPreNode.getParentNode();
if (parentNode != null && parentNode.getChildNodes().size() >= 2) {
Deque<TreeNode<T>> queue = new ArrayDeque<>();
TreeNode<T> rootNode = parentNode;
queue.add(rootNode);
boolean up = false;
while (!queue.isEmpty()) {
rootNode = (TreeNode<T>) queue.poll();
if (up) {
if (rootNode.getFloor() == midPreNode.getFloor()) {
find = rootNode;
}
break;
}
//到了该元素
if (rootNode == midPreNode) up = true;
LinkedList<TreeNode<T>> childNodes = rootNode.getChildNodes();
if (childNodes.size() > 0) {
for (TreeNode<T> item : childNodes) {
queue.add(item);
}
}
}
}
return find;
}
public TreeNode<T> getPreNode(TreeNode<T> midPreNode) {
TreeNode<T> parentNode = midPreNode.getParentNode();
TreeNode<T> find = null;
if (parentNode != null && parentNode.getChildNodes().size() > 0) {
Deque<TreeNode<T>> queue = new ArrayDeque<>();
TreeNode<T> rootNode = parentNode;
queue.add(rootNode);
while (!queue.isEmpty()) {
rootNode = (TreeNode<T>) queue.poll();
//到了该元素
if (rootNode == midPreNode) {
//返回之前的值
break;
}
find = rootNode;
LinkedList<TreeNode<T>> childNodes = rootNode.getChildNodes();
if (childNodes.size() > 0) {
for (TreeNode<T> item : childNodes) {
queue.add(item);
}
}
}
if (find != null && find.getFloor() != midPreNode.getFloor()) {
find = null;
}
}
return find;
}
public ArrayList<TreeNode<T>> getAllLowNodes(TreeNode<T> addNode) {
ArrayList<TreeNode<T>> array = new ArrayList<>();
TreeNode<T> parentNode = addNode.getParentNode();
while (parentNode != null) {
TreeNode<T> lowNode = getLowNode(parentNode);
while (lowNode != null) {
array.add(lowNode);
lowNode = getLowNode(lowNode);
}
parentNode = parentNode.getParentNode();
}
return array;
}
public ArrayList<TreeNode<T>> getAllPreNodes(TreeNode<T> addNode) {
ArrayList<TreeNode<T>> array = new ArrayList<>();
TreeNode<T> parentNode = addNode.getParentNode();
while (parentNode != null) {
TreeNode<T> lowNode = getPreNode(parentNode);
while (lowNode != null) {
array.add(lowNode);
lowNode = getPreNode(lowNode);
}
parentNode = parentNode.getParentNode();
}
return array;
}
public LinkedList<TreeNode<T>> getNodeChildNodes(TreeNode<T> node) {
return node.getChildNodes();
}
public void printTree() {
Stack<TreeNode<T>> stack = new Stack<>();
TreeNode<T> rootNode = getRootNode();
stack.add(rootNode);
while (!stack.isEmpty()) {
TreeNode<T> pop = stack.pop();
System.out.println(pop.getValue().toString());
LinkedList<TreeNode<T>> childNodes = pop.getChildNodes();
for (TreeNode<T> item : childNodes) {
stack.add(item);
}
}
}
public void printTree2() {
Deque<TreeNode<T>> queue = new ArrayDeque<>();
TreeNode<T> rootNode = getRootNode();
queue.add(rootNode);
while (!queue.isEmpty()) {
rootNode = (TreeNode<T>) queue.poll();
System.out.println(rootNode.getValue().toString());
LinkedList<TreeNode<T>> childNodes = rootNode.getChildNodes();
if (childNodes.size() > 0) {
for (TreeNode<T> 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<String> mTree;
private ArrayList<NodeView> 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<String> rootNode = mTree.getRootNode();
Deque<TreeNode<String>> deque = new ArrayDeque<>();
deque.add(rootNode);
while (!deque.isEmpty()) {
TreeNode<String> 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<TreeNode<String>> childNodes = poll.getChildNodes();
for (TreeNode<String> 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<String> treeNode = rootView.getTreeNode();
if (treeNode != null) {
//所有的子节点
LinkedList<TreeNode<String>> 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<TreeNode<String>> queue = new ArrayDeque<>();
TreeNode<String> rootNode = rootView.getTreeNode();
queue.add(rootNode);
while (!queue.isEmpty()) {
rootNode = (TreeNode<String>) 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<TreeNode<String>> childNodes = rootNode.getChildNodes();
for (TreeNode<String> item : childNodes) {
queue.add(item);
}
}
}
private void fatherChildCorrect(NodeView nv) {
int count = nv.getTreeNode().getChildNodes().size();
if (nv.getParent() != null && count >= 2) {
TreeNode<String> tn = nv.getTreeNode().getChildNodes().get(0);
TreeNode<String> 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<TreeNode<String>> allLowNodes = mTree.getAllLowNodes(bn);
ArrayList<TreeNode<String>> allPreNodes = mTree.getAllPreNodes(tn);
for (TreeNode<String> low : allLowNodes) {
NodeView view = findTreeNodeView(low);
moveNodeLayout(view, bnDr);
}
for (TreeNode<String> pre : allPreNodes) {
NodeView view = findTreeNodeView(pre);
moveNodeLayout(view, -topDr);
}
}
}
private void drawTreeLine(Canvas canvas, TreeNode<String> root) {
NodeView fatherView = findTreeNodeView(root);
if (fatherView != null) {
LinkedList<TreeNode<String>> childNodes = root.getChildNodes();
for (TreeNode<String> 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<String> 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<String> tree) {
this.mTree = tree;
onAddNodeViews();
}
public Tree<String> 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<String> treeNode = rootView.getTreeNode();
if (treeNode != null) {
//所有的子节点
LinkedList<TreeNode<String>> 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
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