team2_jj/assets/scripts/core/ui/drag/DragSystem.ts

import { Component, EventTouch, SystemEventType, UITransform, _decorator, Node } from "cc";
import { GeometryUtils } from "../../utils/GeometryUtils";
import { DragSource } from "./DragSource";
import { DragTarget } from "./DragTarget";
const { ccclass, property } = _decorator;
/**
 * 拖拽系统组件
 * @description 主场景中丢这个组件即可
 * @author 袁浩
 */
@ccclass("DragSystem")
export class DragSystem extends Component {
    @property({ tooltip: "可以出发拖拽的节点", type: Node })
    public touchNode: Node;
    private sourceList: DragSource[] = [];
    private targetList: DragTarget[] = [];
    private draggingSource: DragSource;//拖拽中的组件
    private static thisObject: DragSystem;
    start() {
        this.touchNode.on(SystemEventType.TOUCH_MOVE, this.onTouchMove, this);
        this.touchNode.on(SystemEventType.TOUCH_END, this.onTouchEnd, this);
        this.touchNode.on(SystemEventType.TOUCH_CANCEL, this.onTouchEnd, this);
        DragSystem.thisObject = this;
    }
    private onTouchMove(event: EventTouch) {
        if (!this.draggingSource) {//没有进行拖拽
            for (let i = 0; i < this.sourceList.length; i++) {
                if (this.sourceList[i].node.isValid && this.sourceList[i].node.active && this.sourceList[i].getComponent(UITransform).isHit(event.getUILocation())) {//如果跟触摸点碰撞
                    this.draggingSource = this.sourceList[i];
                    this.draggingSource.drag(event);
                    return;
                }
            }
        }
        else {
            this.draggingSource.worldPosition = GeometryUtils.V2ToV3(event.getUILocation());
            for (let i = 0; i < this.targetList.length; i++) {
                let target = this.targetList[i];
                if (target.node.isValid && target.node.active && this.draggingSource.group == target.group) {
                    target.draging(this.draggingSource,this.targetList[i].getComponent(UITransform).isHit(event.getUILocation()), event);
                }
            }
            this.draggingSource.draging(event);
        }
    }
    private onTouchEnd(event: EventTouch) {
        if (!this.draggingSource) {//没有进行拖拽
            return;
        }
        this.draggingSource.drop(event);
        for (let i = 0; i < this.targetList.length; i++) {
            let target = this.targetList[i];
            if (target.node.isValid && target.node.active && this.draggingSource.group == target.group && this.targetList[i].getComponent(UITransform).isHit(event.getUILocation())) {//如果分组相同且跟触摸点碰撞
                target.drop(this.draggingSource, event);
            }
        }
        this.draggingSource.worldPosition = null;
        this.draggingSource = null;
    }
    private addSource(source: DragSource) {
        this.sourceList.push(source);
    }
    private addTarget(target: DragTarget) {
        this.targetList.push(target);
    }
    private removeSource(source: DragSource) {
        let index = this.sourceList.indexOf(source);
        index != -1 && this.sourceList.splice(index, 1);
    }
    private removeTarget(target: DragTarget) {
        let index = this.targetList.indexOf(target);
        index != -1 && this.targetList.splice(index, 1);
    }
    onDestroy() {
        this.touchNode.off(SystemEventType.TOUCH_MOVE, this.onTouchMove, this);
        this.touchNode.off(SystemEventType.TOUCH_END, this.onTouchEnd, this);
        DragSystem.thisObject = null;
    }
    public static addSource(source: DragSource) {
        this.thisObject.addSource(source);
    }
    public static addTarget(target: DragTarget) {
        this.thisObject.addTarget(target);
    }
    public static removeSource(source: DragSource) {
        this.thisObject && this.thisObject.removeSource(source);
    }
    public static removeTarget(target: DragTarget) {
        this.thisObject && this.thisObject.removeTarget(target);
    }
    public static onTouchEnd(event: EventTouch) {
        this.thisObject && this.thisObject.onTouchEnd(event);
    }
    public static get touchNode() {
        return this.thisObject.touchNode;
    }
}