[Unity工具]json查看工具01：TreeView

参考链接：

https://docs.unity3d.com/Manual/TreeViewAPI.html

效果如下：

SimpleTreeView.cs

在添加TreeViewItem节点时，要注意id要唯一，根节点的depth必须为-1

using System.Collections.Generic;
using UnityEditor.IMGUI.Controls;

class SimpleTreeView : TreeView
{
    public SimpleTreeView(TreeViewState treeViewState)
        : base(treeViewState)
    {
        Reload();
    }

    protected override TreeViewItem BuildRoot()
    {
        // BuildRoot is called every time Reload is called to ensure that TreeViewItems 
        // are created from data. Here we create a fixed set of items. In a real world example,
        // a data model should be passed into the TreeView and the items created from the model.

        // This section illustrates that IDs should be unique. The root item is required to 
        // have a depth of -1, and the rest of the items increment from that.
        var root = new TreeViewItem { id = 0, depth = -1, displayName = "Root" };
        var allItems = new List<TreeViewItem>
        {
            new TreeViewItem {id = 1, depth = 0, displayName = "Animals"},
            new TreeViewItem {id = 2, depth = 1, displayName = "Mammals"},
            new TreeViewItem {id = 3, depth = 2, displayName = "Tiger"},
            new TreeViewItem {id = 4, depth = 2, displayName = "Elephant"},
            new TreeViewItem {id = 5, depth = 2, displayName = "Okapi"},
            new TreeViewItem {id = 6, depth = 2, displayName = "Armadillo"},
            new TreeViewItem {id = 7, depth = 1, displayName = "Reptiles"},
            new TreeViewItem {id = 8, depth = 2, displayName = "Crocodile"},
            new TreeViewItem {id = 9, depth = 2, displayName = "Lizard"},
        };

        // Utility method that initializes the TreeViewItem.children and .parent for all items.
        SetupParentsAndChildrenFromDepths(root, allItems);

        // Return root of the tree
        return root;
    }
}

SimpleTreeViewWindow.cs

using UnityEditor;
using UnityEditor.IMGUI.Controls;
using UnityEngine;

class SimpleTreeViewWindow : EditorWindow
{
    // SerializeField is used to ensure the view state is written to the window 
    // layout file. This means that the state survives restarting Unity as long as the window
    // is not closed. If the attribute is omitted then the state is still serialized/deserialized.
    [SerializeField] TreeViewState m_TreeViewState;

    //The TreeView is not serializable, so it should be reconstructed from the tree data.
    SimpleTreeView m_SimpleTreeView;

    void OnEnable()
    {
        // Check whether there is already a serialized view state (state 
        // that survived assembly reloading)
        if (m_TreeViewState == null)
            m_TreeViewState = new TreeViewState();

        m_SimpleTreeView = new SimpleTreeView(m_TreeViewState);
    }

    void OnGUI()
    {
        m_SimpleTreeView.OnGUI(new Rect(0, 0, position.width, position.height));
    }

    // Add menu named "My Window" to the Window menu
    [MenuItem("TreeView Examples/Simple Tree Window")]
    static void ShowWindow()
    {
        // Get existing open window or if none, make a new one:
        var window = GetWindow<SimpleTreeViewWindow>();
        window.titleContent = new GUIContent("My Window");
        window.Show();
    }
}

添加节点的另一种方法(其优点是可以先不指定depth)：

using System.Collections.Generic;
using UnityEditor.IMGUI.Controls;

class SimpleTreeView : TreeView
{
    public SimpleTreeView(TreeViewState treeViewState)
        : base(treeViewState)
    {
        Reload();
    }

    protected override TreeViewItem BuildRoot()
    {
        var root = new TreeViewItem { id = 0, depth = -1, displayName = "Root" };
        var animals = new TreeViewItem { id = 1, displayName = "Animals" };
        var mammals = new TreeViewItem { id = 2, displayName = "Mammals" };
        var tiger = new TreeViewItem { id = 3, displayName = "Tiger" };
        var elephant = new TreeViewItem { id = 4, displayName = "Elephant" };
        var okapi = new TreeViewItem { id = 5, displayName = "Okapi" };
        var armadillo = new TreeViewItem { id = 6, displayName = "Armadillo" };
        var reptiles = new TreeViewItem { id = 7, displayName = "Reptiles" };
        var croco = new TreeViewItem { id = 8, displayName = "Crocodile" };
        var lizard = new TreeViewItem { id = 9, displayName = "Lizard" };

        root.AddChild(animals);
        animals.AddChild(mammals);
        animals.AddChild(reptiles);
        mammals.AddChild(tiger);
        mammals.AddChild(elephant);
        mammals.AddChild(okapi);
        mammals.AddChild(armadillo);
        reptiles.AddChild(croco);
        reptiles.AddChild(lizard);

        SetupDepthsFromParentsAndChildren(root);

        return root;
    }
}