mat-form-field 中未显示下划线

问题描述

我是 angular 的新手。我正在按照 link 中的示例在我的应用中实现扩展部分。我有以下代码。当我点击输入字段时，没有显示下划线。

我的组件中的 html 代码：

  <mat-accordion class="example-headers-align">
<mat-expansion-panel>
  <mat-expansion-panel-header>
    <mat-panel-title>{{ SECTION_HEADER_GENERAL_TITLE }}</mat-panel-title>
    <mat-panel-description>
      <mat-icon>{{ SECTION_HEADER_GENERAL_ICON }}</mat-icon>
      {{ SECTION_HEADER_GENERAL_DESCRIPTION }}
    </mat-panel-description>
  </mat-expansion-panel-header>

  <mat-form-field appearance="fill"> 
    <mat-label>{{ GENERAL_FIELD_NAME_LABEL }}</mat-label>
    <input matInput >
  </mat-form-field></mat-expansion-panel>  </mat-accordion>

当我使用“检查元素”并检查与下划线对应的 div 时，它似乎由于某种原因被禁用：

下面是火狐浏览器输入框的图片。

我的 component.scss 文件是空的，我没有任何特定于组件的 css。

app.module.ts：

import { NgModule,CUSTOM_ELEMENTS_SCHEMA  } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { browserAnimationsModule } from '@angular/platform-browser/animations';
import { AppComponent } from './components/main-app/app.component';
import { LoginComponent } from './components/login/login.component';
import { FlexLayoutModule } from "@angular/flex-layout";
import { LayoutModule } from '@angular/cdk/layout';
import { MatToolbarModule } from '@angular/material/toolbar';
import { MatButtonModule } from '@angular/material/button';
import { MatSidenavModule } from '@angular/material/sidenav';
import { MatIconModule } from '@angular/material/icon';
import { MatListModule } from '@angular/material/list';
import {MatCardModule} from '@angular/material/card';
import {MatTableModule} from '@angular/material/table';
import { RestService } from './service/rest-services/rest.service';
import { AppConstants } from './constants/app-constants';
import { HttpClientModule } from '@angular/common/http';
import {NgbModule} from '@ng-bootstrap/ng-bootstrap';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatDatepickerModule } from '@angular/material/datepicker';
import { DatepickerApiComponent } from './datepicker-api/datepicker-api.component';
import { MatNativeDateModule,MAT_DATE_LOCALE,MAT_DATE_FORMATS,DateAdapter } from '@angular/material/core';
import { FormsModule,ReactiveFormsModule } from '@angular/forms';
import { AppDateFormatAdapter,APP_DATE_FORMATS } from './datepicker-api/AppDateFormatAdapter';
import { MatTabsModule } from '@angular/material/tabs';
import { NgxSpinnerModule } from "ngx-spinner";
import { createuserComponent } from './components/create-user/create-user.component';
import {MatPaginatorModule} from '@angular/material/paginator';
import {MatSortModule} from '@angular/material/sort';
import {MatExpansionModule} from '@angular/material/expansion';
import {MatDialogModule } from '@angular/material/dialog';
import {MessageComponent} from './components/message/message.component';
import {MatInputModule} from '@angular/material/input';
import {MatSelectModule} from '@angular/material/select';
import {MaTradioModule} from '@angular/material/radio'; 
import { RolesComponent } from './components/roles/roles.component';
import {AuthService } from './service/rest-services/authentication.service';
import { HomeComponent } from './components/home/home.component';
import { MatCheckBoxModule } from '@angular/material/checkBox';
import { MatStepperModule } from '@angular/material/stepper';
import { StepperComponent } from './components/stepper/stepper.component';
@NgModule({
  declarations: [
    AppComponent,DatepickerApiComponent,StepperComponent,],imports: [
    browserModule,AppRoutingModule,browserAnimationsModule,LayoutModule,MatToolbarModule,MatButtonModule,MatSidenavModule,MatIconModule,MatListModule,MatCardModule,MatTableModule,HttpClientModule,NgbModule,MatFormFieldModule,MatDatepickerModule,MatNativeDateModule,FormsModule,ReactiveFormsModule,MatTabsModule,MatPaginatorModule,NgxSpinnerModule,MatSortModule,MatStepperModule,MatExpansionModule,MatDialogModule,MatInputModule,MatSelectModule,MaTradioModule,MatCheckBoxModule,FlexLayoutModule,entryComponents: [MessageComponent],schemas: [CUSTOM_ELEMENTS_SCHEMA],providers: [RestService,AppConstants,AuthService,AlmInterfaceService,{provide:DateAdapter,useClass:AppDateFormatAdapter},{provide:MAT_DATE_FORMATS,useValue:APP_DATE_FORMATS}
  ],bootstrap: [AppComponent]
})
export class AppModule { }

Package.json

  "name": "ca-application","version": "0.0.0","scripts": {
    "ng": "ng","start": "ng serve","build": "ng build","test": "ng test","lint": "ng lint","e2e": "ng e2e"
  },"private": true,"dependencies": {
    "@angular/animations": "~9.1.9","@angular/cdk": "^9.2.4","@angular/common": "~9.1.9","@angular/compiler": "~9.1.9","@angular/core": "~9.1.9","@angular/flex-layout": "^9.0.0-beta.31","@angular/forms": "~9.1.9","@angular/localize": "^9.1.11","@angular/material": "^9.2.4","@angular/platform-browser": "~9.1.9","@angular/platform-browser-dynamic": "~9.1.9","@angular/router": "~9.1.9","@ng-bootstrap/ng-bootstrap": "^6.1.0","bootstrap": "^4.5.0","file-saver": "^2.0.5","ngx-spinner": "^9.0.2","rxjs": "~6.5.4","tslib": "^1.10.0","zone.js": "~0.10.2"
  },"devDependencies": {
    "@angular-devkit/build-angular": "^0.901.12","@angular/cli": "~9.1.7","@angular/compiler-cli": "~9.1.9","@types/jasmine": "~3.5.0","@types/jasminewd2": "~2.0.3","@types/node": "^12.11.1","codelyzer": "^5.1.2","jasmine-core": "~3.5.0","jasmine-spec-reporter": "~4.2.1","karma": "~5.0.0","karma-chrome-launcher": "~3.1.0","karma-coverage-istanbul-reporter": "~2.1.0","karma-jasmine": "~3.0.1","karma-jasmine-html-reporter": "^1.4.2","protractor": "~7.0.0","ts-node": "~8.3.0","tslint": "~6.1.0","typescript": "~3.8.3"
  }
}

你能告诉我我做错了什么吗？

解决方法

看这里，您可能需要手动设置 mat-focused 以获得更好的视图