创建复杂的列表视图
此示例演示如何创建复杂的 ListView。
示例概述
该示例创建一个包含字符列表的自定义编辑器窗口。每个角色都有一个滑块和一个调色板。移动滑块会更改调色板的颜色。
您可以在此 GitHub 存储库中找到此示例创建的已完成文件。
先决条件
本指南适用于熟悉 Unity 编辑器、UI 工具包和 C# 脚本的开发人员。在开始之前，请熟悉以下内容：
创建示例
此示例构建视觉元素实例化或派生自 C# 的可视化树的节点VisualElement类。您可以设置外观样式、定义行为并将其作为 UI 的一部分显示在屏幕上。更多信息
请参阅术语表在 C# 脚本的列表中。它使用自定义CharacterInfoVisualElement继承自VisualElement，并将自定义元素绑定到CharacterInfo对象。
- 使用任何模板创建 Unity 项目。
- 在项目窗口一个窗口，显示您的内容
Assets文件夹（项目选项卡）更多信息
在术语表中查看，创建一个名为Editor. - 在
Editor文件夹中，创建一个名为ListViewExample.cs内容如下：
using System;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;
namespace UIToolkitExamples {
public class ListViewExample: EditorWindow {
// Gradient used for the HP color indicator.
private Gradient hpGradient;
private GradientColorKey[] hpColorKey;
private GradientAlphaKey[] hpAlphaKey;
// ListView is kept for easy reference.
private ListView listView;
// List of CharacterInfo items, bound to the ListView.
private List < CharacterInfo > items;
[MenuItem("Window/ListView Custom Item")]
public static void OpenWindow() {
GetWindow < ListViewExample > ().Show();
}
private void OnEnable() {
SetGradient();
// Create and populate the list of CharacterInfo objects.
const int itemCount = 50;
items = new List < CharacterInfo > (itemCount);
for (int i = 1; i <= itemCount; i++) {
CharacterInfo character = new CharacterInfo {
name = $"Character {i}", maxHp = 100
};
character.currentHp = character.maxHp;
items.Add(character);
}
// The ListView calls this to add visible items to the scroller.
Func < VisualElement > makeItem = () => {
var characterInfoVisualElement = new CharacterInfoVisualElement();
var slider = characterInfoVisualElement.Q < SliderInt > (name: "hp");
slider.RegisterValueChangedCallback(evt => {
var hpColor = characterInfoVisualElement.Q < VisualElement > ("hpColor");
var i = (int) slider.userData;
var characterInfo = items[i];
characterInfo.currentHp = evt.newValue;
SetHp(slider, hpColor, characterInfo);
});
return characterInfoVisualElement;
};
// The ListView calls this if a new item becomes visible when the item first appears on the screen,
// when a user scrolls, or when the dimensions of the scroller are changed.
Action < VisualElement, int > bindItem = (e, i) => BindItem(e as CharacterInfoVisualElement, i);
// Height used by the ListView to determine the total height of items in the list.
int itemHeight = 55;
// Use the constructor with initial values to create the ListView.
listView = new ListView(items, itemHeight, makeItem, bindItem);
listView.reorderable = false;
listView.style.flexGrow = 1f; // Fills the window, at least until the toggle below.
listView.showBorder = true;
rootVisualElement.Add(listView);
// Add a toggle to switch the reorderable property of the ListView.
var reorderToggle = new Toggle("Reorderable");
reorderToggle.style.marginTop = 10f;
reorderToggle.value = false;
reorderToggle.RegisterValueChangedCallback(evt => listView.reorderable = evt.newValue);
rootVisualElement.Add(reorderToggle);
}
// Sets up the gradient.
private void SetGradient() {
hpGradient = new Gradient();
// HP at 0%: Red. At 10%: Dark orange. At 40%: Yellow. At 100%: Green.
hpColorKey = new GradientColorKey[4];
hpColorKey[0] = new GradientColorKey(Color.red, 0f);
hpColorKey[1] = new GradientColorKey(new Color(1f, 0.55f, 0f), 0.1f); // Dark orange
hpColorKey[2] = new GradientColorKey(Color.yellow, 0.4f);
hpColorKey[3] = new GradientColorKey(Color.green, 1f);
// Alpha is always full.
hpAlphaKey = new GradientAlphaKey[2];
hpAlphaKey[0] = new GradientAlphaKey(1f, 0f);
hpAlphaKey[1] = new GradientAlphaKey(1f, 1f);
hpGradient.SetKeys(hpColorKey, hpAlphaKey);
}
// Bind the data (characterInfo) to the display (elem).
private void BindItem(CharacterInfoVisualElement elem, int i) {
var label = elem.Q < Label > (name: "nameLabel");
var slider = elem.Q < SliderInt > (name: "hp");
var hpColor = elem.Q < VisualElement > ("hpColor");
slider.userData = i;
CharacterInfo characterInfo = items[i];
label.text = characterInfo.name;
SetHp(slider, hpColor, characterInfo);
}
private void SetHp(SliderInt slider, VisualElement colorIndicator, CharacterInfo characterInfo) {
slider.highValue = characterInfo.maxHp;
slider.SetValueWithoutNotify(characterInfo.currentHp);
float ratio = (float) characterInfo.currentHp / characterInfo.maxHp;
colorIndicator.style.backgroundColor = hpGradient.Evaluate(ratio);
}
// This class inherits from VisualElement to display and modify data to and from a CharacterInfo.
public class CharacterInfoVisualElement: VisualElement {
// Use Constructor when the ListView uses makeItem and returns a VisualElement to be
// bound to a CharacterInfo data class.
public CharacterInfoVisualElement() {
var root = new VisualElement();
// The code below to style the ListView is for demo purpose. It's better to use a USS file
// to style a visual element.
root.style.paddingTop = 3f;
root.style.paddingRight = 0f;
root.style.paddingBottom = 15f;
root.style.paddingLeft = 3f;
root.style.borderBottomColor = Color.gray;
root.style.borderBottomWidth = 1f;
var nameLabel = new Label() {
name = "nameLabel"
};
nameLabel.style.fontSize = 14f;
var hpContainer = new VisualElement();
hpContainer.style.flexDirection = FlexDirection.Row;
hpContainer.style.paddingLeft = 15f;
hpContainer.style.paddingRight = 15f;
hpContainer.Add(new Label("HP:"));
var hpSlider = new SliderInt {
name = "hp", lowValue = 0, highValue = 100
};
hpSlider.style.flexGrow = 1f;
hpContainer.Add(hpSlider);
var hpColor = new VisualElement();
hpColor.name = "hpColor";
hpColor.style.height = 15f;
hpColor.style.width = 15f;
hpColor.style.marginRight = 5f;
hpColor.style.marginBottom = 5f;
hpColor.style.marginLeft = 5f;
hpColor.style.backgroundColor = Color.black;
hpContainer.Add(hpColor);
root.Add(nameLabel);
root.Add(hpContainer);
Add(root);
}
}
// Basic data class used for a character, with a name and HP data. Use a list of CharacterInfo as
// a data source for the ListView. The CharacterInfo can be bound to CharacterInfoVisualElement when needed.
[Serializable]
public class CharacterInfo {
public string name;
public int maxHp;
public int currentHp;
}
}
}
- 若要查看示例，请从菜单中选择“窗口”>“ListView 自定义项”。