cocoscreator一次性加载resources全部的资源

1：一次性加载全部资源，这样就不用每次都异步load了

cc.resources.loadDir("./", (err, assets : cc.Asset[])=>{

    let list = cc.resources.getDirWithPath("./")
    let uuidDict = {}

    for(let item of list) {
        uuidDict[item.uuid] = item
    }

    let resList = {}
    
    for(let asset of assets) {
        let path = uuidDict[asset["_uuid"]].path
        if(!resList[path]) {
            resList[path] = []
        }
        resList[path].push(asset)
    }
    this.resList = resList

})

2：根据路径获取对应的资源

getRes(path, type) {
    let list = this.resList[path]

    if(!list) {
        return null
    }

    for(let item of list) {
        if(item instanceof(type)) {
            return item
        }
    }

    return null
}