【cocos creator】【ts】事件派发系统

触发使用：
EventTool.emit(“onClick”)
需要监听的地方，onload调用：
EventTool.on(“onClick”, this.onClickEvent, this)

/**事件派发*/

class EventTool {

    protected static _instance: EventTool = null;

    public static get Instance(): EventTool {
        if (EventTool._instance == null) {
            EventTool._instance = new EventTool();
        }
        return EventTool._instance;
    }

    isValidNode(node) {
        return node && node.isValid;
    }
    /**添加事件监听  
     * @param {string} event 事件名  
     * @param {Function} handler 事件响应函数  
     * @param {object} scope 函数所在的对象
     */
    on(event: any, handler: Function, scope: any) {
        if (typeof handler != "function") {
            console.error("没有事件响应函数！", event);
            return;
        }
        let id = scope.uuid || scope.__custom_id__;
        if (!id) {
            scope.__custom_id__ = "" + Date.now() + Math.random();
            id = scope.__custom_id__;
        }
        this[id] = this[id] == undefined ? [] : this[id];
        if (Array.isArray(this[id])) {
            this[id].push(event);
        } else {
            console.error("有一个跟当前脚本同名的事件！");
            return;
        }
        this[event] = this[event] ? this[event] : {};
        this[event][id] = { handler: handler, scope: scope, times: cc.macro.REPEAT_FOREVER };
    }

    onOnce(event, handler, scope) {
        this.on(event, handler, scope)
        let id = scope.uuid || scope.__custom_id__;
        this[event][id].times = 1
    }

    /**
     * 移除事件监听
     * @param scope 
     * @param event event 为空则移除scope所有监听
     */
    off(scope?: any, event?: any) {
        let id = scope.uuid || scope.__custom_id__;
        if (!id) {
            return;
        }
        if (event) {
            this[event] = this[event] ? this[event] : {};
            this[event][id] = null;
            delete this[event][id];
            return;
        }
        let events = this[id];
        if (Array.isArray(events)) {
            for (let i = 0; i < events.length; i++) {
                this[events[i]][id] = null;
                delete this[events[i]][id];
            }
        }
        this[id] = [];
        delete this[id];
    }

    /**发送事件  
     * 参数个数不限，第一个参数为事件名，其余为传递给响应函数的参数  
     * @param {string} event 事件名    
     * @param args {}传递给响应函数的参数集，可以为空 
     */
    emit<T>(event, ...args) {
        let onwers = this[event];
        // console.log("trigger event:" + event);
        if (onwers) {
            for (let key in onwers) {
                let data = onwers[key];
                if (--data.times <= 0) {
                    delete onwers[key];
                }
                try {
                    if (!data.scope || !data.scope.node || !data.handler) continue;
                    data.handler.apply(data.scope, args);
                } catch (e) {
                    // console.error(e)
                }
            }
        } else {
            // console.log(event + "事件还没有添加事件监听!");
        }
    }
};
export default EventTool.Instance