Question

我正在使用Model–view–controller设计模式，我需要一个用于我的BST / AVL模型的UI查看器，我已经开发了模型和控制器逻辑，我只需要查看器，我这样做现在不需要处理图形，如果某人有一个 Viewer 类，其方法采用树的根并绘制它，不需要高级动画或效果，那将非常有用

类似

SimpleBSTreeViewer.draw(myTree.getRoot());

树的节点结构

public class NodeBST <T extends Comparable<T>> {
 private T data;
 private NodeBST<T> left;
 private NodeBST<T> right;
 private NodeBST<T> parent;

 //other methods go here ...
}

这将有助于编写逻辑部分的重点，

我搜索过并找到了其他代表树的小程序，但它们在同一个类中有模型逻辑和视图，我在模型 - 视图 - 控制器模式（MVC模式）中工作，最好将模型与视图分开尽可能地，我只想要一个观众用于我的模型

注意：这是我需要的样本（我已经使用了JTree，但这并不令人满意。）

enter image description here

Answer 1

获取Jgraphx库并从HelloWorld开始我编写此类的例子

使用this问题计算节点的坐标。

package algorithms.searching.bst;

import java.util.Random;

import javax.swing.JFrame;

import log.Logger;

import algorithms.searching.bst.avl.AVL;

import com.mxgraph.swing.mxGraphComponent;
import com.mxgraph.view.mxGraph;

@SuppressWarnings("serial")

public class TreeViewer<T extends Comparable<T>> extends JFrame {

static private int CANVAS_HEIGHT = 600;
static private int CANVAS_WIDTH = 1000;

private int rootY = 10;
private int NODE_SIZE = 25;
private int ROW_HEIGHT = 50;
mxGraph graph = new mxGraph();
Object parent = graph.getDefaultParent();

/**
 * draws a tree starting from this root
 * 
 * @param root
 * @param depth
 *            number of nodes to the root (including root)
 * @param index
 *            index of node in this level (leftChildIndex = parentIndex * 2
 *            - 1) and (rightChildIndex = parentIndex * 2)
 * @return
 */
public Object drawTree(NodeBST<T> root, int depth, int index) {
    if (root == null) {
        return null;
    }

    // draw root

    /*
     * leftChildIndex = parentIndex * 2 - 1 
     * rightChildIndex = parentIndex *2
     *
     *
     * x = index * canvasWidth / (2^depth + 1)
     *
     * y = depth * canvasHeight / treeDepth
     */

    int myX = (int) ((CANVAS_WIDTH * (index)) / (Math.pow(2, depth - 1) + 1));

    Object rootVertex = graph.insertVertex(parent, null, root.getData(),
            myX, depth * ROW_HEIGHT + rootY, NODE_SIZE, NODE_SIZE);

    Logger.log("new x coordinate=" + myX);

    // recurse for right child

    Object rightChildVertex = drawTree(root.getRight(), depth + 1,
            index * 2);

    if (rightChildVertex != null) {// edge
        graph.insertEdge(parent, null, "R", rootVertex, rightChildVertex,
                "startArrow=none;endArrow=none;strokeWidth=1;strokeColor=green");
    }

    Object leftChildVertex = drawTree(root.getLeft(), depth + 1,
            index * 2 - 1);

    // recurse for right child

    if (leftChildVertex != null) { // edge
        graph.insertEdge(parent, null, "L", rootVertex, leftChildVertex,
                "startArrow=none;endArrow=none;strokeWidth=1;strokeColor=green");
    }

    return rootVertex;

}

/**
 * Redraw the whole tree
 * 
 * @param root
 *            the root of tree to be drawn
 */

public void update(NodeBST<T> root) {

    graph.getModel().beginUpdate();

    try {

        Object[] cells = graph.getChildCells(parent, true, false);
        graph.removeCells(cells, true);
        drawTree(root, 1, 1);

    } finally {
        graph.getModel().endUpdate();
    }
}

public TreeViewer(NodeBST<T> root) {
    // super("Hello, World!");

    this.update(root);

    mxGraphComponent graphComponent = new mxGraphComponent(graph);

    getContentPane().add(graphComponent);
}

public static void main(String[] args) {

    AVL<Integer> bst = new AVL<Integer>();//use AVL tree class 

    Random randomGenerator = new Random();
    for (int i = 0; i < 20; i++) {//try generating 20 random integers
        bst.insert(randomGenerator.nextInt(1000));
    }

    TreeViewer<Integer> myTreeViewer=new TreeViewer<Integer>(bst.getRoot());
    JFrame frame = myTreeViewer;

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(CANVAS_WIDTH, CANVAS_HEIGHT);
    frame.setVisible(true);

}



}

只需修改此类即可获取树类
非常感谢NeplatnyUdaj！

Viewing AVL tree

java中需要BST图形表示

1 个答案: