扩展UICallbacks对象，添加网络异常时，窗口加载失败回调。方便处理异常时的游戏体验逻辑

assets/core/gui/layer/Defines.ts

@@ -30,7 +30,10 @@ export interface UICallbacks {
      * @param node   当前界面节点
      * @param next   回调方法
      */
-    onBeforeRemove?: (node: Node, next: Function) => void
+    onBeforeRemove?: (node: Node, next: Function) => void,
+
+    /** 网络异常时，窗口加载失败回调 */
+    onLoadFailure?: () => void;
 }
 
 /** 本类型仅供gui模块内部使用，请勿在功能逻辑中使用 */

assets/core/gui/layer/DelegateComponent.ts

@@ -37,9 +37,7 @@ export class DelegateComponent extends Component {
             if (typeof this.vp.callbacks.onBeforeRemove === "function") {
                 this.vp.callbacks.onBeforeRemove(
                     this.node,
-                    () => {
-                        this.removed(this.vp, isDestroy);
-                    });
+                    this.onBeforeRemoveNext.bind(this, isDestroy));
             }
             else {
                 this.removed(this.vp, isDestroy);
@@ -47,6 +45,11 @@ export class DelegateComponent extends Component {
         }
     }
 
+    /** 窗口关闭前动画处理完后的回调方法，主要用于释放资源 */
+    private onBeforeRemoveNext(isDestroy?: boolean) {
+        this.removed(this.vp, isDestroy);
+    }
+
     /** 窗口组件中触发移除事件与释放窗口对象 */
     private removed(vp: ViewParams, isDestroy?: boolean) {
         vp.valid = false;

assets/core/gui/layer/LayerManager.ts

@@ -191,7 +191,10 @@ export class LayerManager {
         return new Promise<Node | null>((resolve, reject) => {
             var callbacks: UICallbacks = {
                 onAdded: (node: Node, params: any) => {
-                    resolve(node)
+                    resolve(node);
+                },
+                onLoadFailure: () => {
+                    resolve(null);
                 }
             };
             this.open(uiId, uiArgs, callbacks);

assets/core/gui/layer/LayerUI.ts

@@ -1,4 +1,4 @@
-import { error, instantiate, Node, Prefab, warn, Widget } from "cc";
+import { instantiate, Node, Prefab, Widget } from "cc";
 import { oops } from "../../Oops";
 import { UICallbacks, ViewParams } from "./Defines";
 import { DelegateComponent } from "./DelegateComponent";
@@ -35,7 +35,7 @@ export class LayerUI extends Node {
      */
     add(config: UIConfig, params?: any, callbacks?: UICallbacks) {
         if (this.ui_nodes.has(config.prefab)) {
-            warn(`路径为【${config.prefab}】的预制重复加载`);
+            console.warn(`路径为【${config.prefab}】的预制重复加载`);
             return;
         }
 
@@ -69,7 +69,8 @@ export class LayerUI extends Node {
             oops.res.load(bundle, vp.config.prefab, (err: Error | null, res: Prefab) => {
                 if (err) {
                     this.ui_nodes.delete(vp.config.prefab);
-                    error(`路径为【${vp.config.prefab}】的预制加载失败`);
+                    console.warn(`路径为【${vp.config.prefab}】的预制加载失败`);
+                    vp.callbacks && vp.callbacks.onLoadFailure && vp.callbacks.onLoadFailure();
                     return;
                 }
 

assets/libs/collection/List.ts

@@ -1,5 +1,5 @@
 /** 列表 */
-export class List<T>  {
+export class List<T> {
     private element: Array<T>;
 
     /** 是否保证元素的唯一性 */
@@ -54,9 +54,9 @@ export class List<T>  {
         if (this.element.length > 0) {
             const result = this.element.pop();
             this.count = this.element.length;
-            return result;
+            return result!;
         }
-        return null;
+        return null!;
     }
 
     /**
@@ -67,9 +67,9 @@ export class List<T>  {
         if (this.element.length > 0) {
             const result = this.element.shift();
             this.count = this.element.length;
-            return result;
+            return result!;
         }
-        return null;
+        return null!;
     }
 
     /**