【问题标题】:After upgrading to Angular 6, application shows blank white screen升级到 Angular 6 后,应用程序显示空白屏幕
【发布时间】:2019-09-29 02:59:55
【问题描述】:

我已按照https://update.angular.io/ 给出的步骤进行操作 升级到 Angular 6 后,应用程序显示所有路线的空白屏幕。而且浏览器控制台中也没有显示错误。每个路由重定向到默认路径http://localhost:4200。 但是http://localhost:4200/admin 工作正常。

任何人都可以帮忙,可能是什么问题? 您需要我提供什么信息来重现该问题?

这里是依赖列表:

"dependencies": {
    "@angular/animations": "6.0.3",
    "@angular/cdk": "^6.2.0",
    "@angular/common": "6.0.3",
    "@angular/compiler": "6.0.3",
    "@angular/core": "6.0.3",
    "@angular/forms": "6.0.3",
    "@angular/http": "6.0.3",
    "@angular/material": "^6.2.0",
    "@angular/material-moment-adapter": "^6.2.0",
    "@angular/platform-browser": "6.0.3",
    "@angular/platform-browser-dynamic": "6.0.3",
    "@angular/router": "6.0.3",
    "@ng-bootstrap/ng-bootstrap": "^2.0.0",
    "@ngx-translate/core": "^10.0.2",
    "@ngx-translate/http-loader": "^3.0.1",
    "@swimlane/ngx-charts": "^8.0.2",
    "@types/lodash": "^4.14.87",
    "bootstrap": "4.0.0",
    "chart.js": "^2.7.2",
    "classlist.js": "^1.1.20150312",
    "codelyzer": "^4.3.0",
    "core-js": "^2.5.1",
    "font-awesome": "^4.7.0",
    "lodash": "^4.17.4",
    "moment": "^2.19.3",
    "ng2-charts": "^1.6.0",
    "ng2-dragula": "^1.3.1",
    "ng2-file-upload": "^1.3.0",
    "ng4-charts": "^1.0.2",
    "rxjs": "^6.2.0",
    "web-animations-js": "^2.2.5",
    "zone.js": "^0.8.19"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.6.6",
    "@angular/cli": "^6.0.7",
    "@angular/compiler-cli": "6.0.3",
    "@types/jasmine": "2.5.38",
    "@types/node": "^6.0.92",
    "jasmine-core": "~2.5.2",
    "jasmine-spec-reporter": "~3.2.0",
    "karma": "~1.4.1",
    "karma-chrome-launcher": "~2.0.0",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^0.2.0",
    "karma-jasmine": "^1.1.1",
    "karma-jasmine-html-reporter": "^0.2.2",
    "node-sass": "^4.7.2",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "tslint": "~5.10.0",
    "typescript": "^2.7.2"
  }

angular.json

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "bcare": {
      "root": "",
      "sourceRoot": "src",
      "projectType": "application",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist",
            "index": "src/index.html",
            "main": "src/main.ts",
            "tsConfig": "src/tsconfig.app.json",
            "polyfills": "src/polyfills.ts",
            "assets": [
              "src/assets"
            ],
            "styles": [
              "src/fonts.scss",
              "src/styles.scss"
            ],
            "scripts": []
          },
          "configurations": {
            "prod": {
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ]
            }
          }
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "bcare:build"
          },
          "configurations": {
            "prod": {
              "browserTarget": "bcare:build:prod"
            }
          }
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "browserTarget": "bcare:build"
          }
        },
        "test": {
          "builder": "@angular-devkit/build-angular:karma",
          "options": {
            "main": "src/test.ts",
            "karmaConfig": "./karma.conf.js",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.spec.json",
            "scripts": [],
            "styles": [
              "src/fonts.scss",
              "src/styles.scss"
            ],
            "assets": [
              "src/assets"
            ]
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "src/tsconfig.app.json",
              "src/tsconfig.spec.json"
            ],
            "exclude": []
          }
        }
      }
    },
    "bcare-e2e": {
      "root": "",
      "sourceRoot": "",
      "projectType": "application",
      "architect": {
        "e2e": {
          "builder": "@angular-devkit/build-angular:protractor",
          "options": {
            "protractorConfig": "./protractor.conf.js",
            "devServerTarget": "bcare:serve"
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "e2e/tsconfig.e2e.json"
            ],
            "exclude": []
          }
        }
      }
    }
  },
  "defaultProject": "bcare",
  "schematics": {
    "@schematics/angular:component": {
      "prefix": "cc",
      "styleext": "scss"
    },
    "@schematics/angular:directive": {
      "prefix": "cc"
    }
  }
}

app-routing.module.ts

import {RouterModule, Routes} from '@angular/router';
import {NotFoundComponent} from './core/main/not-found.component';
import {HomeComponent} from './core/main/home/home.component';
import {LoginComponent} from './core/main/login/login.component';
import {NgModule} from '@angular/core';
import {HomeGuard} from './core/main/home/home.guard';
import {CanLoadAdmin} from './core/services/can-load-admin';
import {RulesPreviewComponent} from './branches/preparation-admin/main/rules/rules-preview/rules-preview.component';

export const APP_ROUTES: Routes = [
    {
        path: '',
        component: HomeComponent,
        canActivate: [HomeGuard],
        children: [
            {
                path: '',
                redirectTo: 'preparation',
                pathMatch: 'full'
            },
            {
                path: 'preparation',
                loadChildren: 'app/branches/preparation/preparation.module#PreparationModule'
            },
            {
                path: 'admin',
                loadChildren: 'app/admin/admin/admin.module#AdminModule',
                canLoad: [CanLoadAdmin]
            }
        ]
    },
    {path: 'login', component: LoginComponent},
    {path: 'email-preview/:id', component: RulesPreviewComponent},
    {path: '**', component: NotFoundComponent},
];


@NgModule({
    imports: [RouterModule.forRoot(APP_ROUTES)],
    exports: [RouterModule]
})
export class AppRoutingModule {
}

【问题讨论】:

  • 你检查浏览器控制台了吗?有没有错误?如果有,请将它们包含在您的问题中。
  • 浏览器控制台没有错误
  • 当您使用“ng serve”运行您的应用程序时,您是否在 cli 中看到任何错误,或者它是否可以正常构建和运行?
  • 不,构建或服务中没有错误。
  • 显示文件结构以及您的 angular.json 文件会很有帮助。

标签: angular angular6


【解决方案1】:

从 Angular 5 更新到 6 后,我遇到了同样的问题。

我发现 Angular 根本没有加载到我的应用程序中,我什至没有收到消息“Angular is running in the development mode. Call enableProdMode() to enable the production mode.” 经过一番挖掘后,我注意到使用 Angular 6 生成的文件之一是不同的。在它生成inline.jspolyfills.jsscripts.jsvendor.jsmain.js 之前。从 Angular 6 开始,它现在生成 runtime.js 而不是 inline.js。我一直在使用 Angular 和 MVC,所以我直接引用了输出文件。我将引用从 inline.* 更改为 runtime.*(对于 MVC,它在 BundlesConfig.cs 中),一切都再次正确。

生成的文件应该在/dist/ 中生成,除非你改变了它。可以在angular.jsonprojects -> my-project-name -> architect -> build -> options -> outputPath下确认路径。

我在升级时遇到的另一个问题也可能与您的问题有关,因为 ng build 的 -ec 参数不再适用于 Angular 6,所以我的 css 文件不再生成;你现在必须使用 --extract-css。

希望对您有所帮助。

【讨论】:

    【解决方案2】:

    我在使用 Angular 6 时遇到了类似的行为。对于之前的版本,当您遇到路由错误时,它们会以推送状态而不是真正的导航重定向到默认根目录。

    这对您意味着什么:为了查看错误,请在浏览器控制台中激活“保留日志”(例如,在 Chrome 中单击齿轮符号并设置复选框),然后重试。错误应该会出现,您可以继续解决它们。

    【讨论】:

    • 我已经尝试过了。它仍然没有显示任何错误。
    【解决方案3】:

    您需要检查您的提供程序,因为不需要在 app.module 文件中包含您的提供程序。您能否在控制台中提供一些详细信息,例如您的代码和错误,这会有所帮助

    【讨论】:

    • 我添加了更多细节。构建或服务没有错误。不在浏览器控制台中。
    【解决方案4】:

    你可能会犯这个错误。如果您在浏览器的控制台视图中打开应用程序,您会看到这一点。

    NullInjectorError: 没有 ApplicationRef 的提供者!

    如果是这样,将 BrowserModule 导入 app.module.ts 将解决您的问题。

    import { BrowserModule } from '@angular/platform-browser';
    

    您可以查看相关答案here

    【讨论】:

      【解决方案5】:

      您必须在 index.html 文件中进行更改: 更改为然后运行 ​​ng build --prod

      【讨论】:

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