Angular7:Materials/CDK-拖拽
添加到Angular7 CDK的新拖放功能有助于从列表中拖放元素。借助一个例子,我们将了解拖放模块的工作原理。该功能被添加到cdk。我们需要首先下载依赖关系,如下所示
npm install @angular/cdk --save
拖放功能
一旦完成上述步骤。让我们在app.module.ts中导入拖放模块,如下所示.
import { BrowserModule } from '@angular/platform-browser'; import { NgModule } from '@angular/core'; import { AppRoutingModule , RoutingComponent} from './app-routing.module'; import { AppComponent } from './app.component'; import { NewCmpComponent } from './new-cmp/new-cmp.component'; import { ChangeTextDirective } from './change-text.directive'; import { SqrtPipe } from './app.sqrt'; import { MyserviceService } from './myservice.service'; import { HttpClientModule } from '@angular/common/http'; import { ScrollDispatchModule } from '@angular/cdk/scrolling'; import { DragDropModule } from '@angular/cdk/drag-drop'; @NgModule({ declarations: [ SqrtPipe, AppComponent, NewCmpComponent, ChangeTextDirective, RoutingComponent ], imports: [ BrowserModule, AppRoutingModule, HttpClientModule, ScrollDispatchModule, DragDropModule ], providers: [MyserviceService], bootstrap: [AppComponent] }) export class AppModule { }
DragDropModule是从“@angular/cdk/drag-drop”导入的,该模块被添加到导入数组中,如上所示。
我们将使用API(http://jsonplaceholder.typicode.com/users)中的详细信息显示在屏幕上。我们有如下所示从api获取数据的服务
myservice.service.ts
import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; @Injectable({ providedIn: 'root' }) export class MyserviceService { private finaldata = []; private apiurl = "http://jsonplaceholder.typicode.com/users"; constructor(private http: HttpClient) { } getData() { return this.http.get(this.apiurl); } }
完成后,调用app.component.ts内部的服务,如下所示.
import { Component } from '@angular/core'; import { MyserviceService } from './myservice.service'; @Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'] }) export class AppComponent { title = 'Angular 7 Project!'; public personaldetails = []; constructor(private myservice: MyserviceService) {} ngOnInit() { this.myservice.getData().subscribe((data) => { this.personaldetails = Array.from(Object.keys(data), k=>data[k]); console.log(this.personaldetails); }); } }
我们在personaldetails变量中有所需的数据。现在让我们使用同样的方法显示给用户,如下所示
<h3>Angular 7 - Drag and Drop Module</h3> <div> <div *ngFor="let item of personaldetails; let i = index" class="divlayout”> {{item.name}} </div > </div>
我们添加了class = "divlayout ",该类的详细信息在app.component.css中。
.divlayout{ width: 40%; background-color: #ccc; margin-bottom: 5px; padding: 10px 10px; border: 3px solid #73AD21; }
浏览器中将显示以下屏幕
它暂时没有拖放效果,我们需要在app.component.html添加拖放cdk属性,如下所示
<h3>Angular 7 - Drag and Drop Module</h3> <div cdkDropList #personList = "cdkDropList" [cdkDropListData] = "personaldetails" [cdkDropListConnectedTo] = "[userlist]" class = "example-list" (cdkDropListDropped) = "onDrop($event)" > <div *ngFor = "let item of personaldetails; let i = index" class = "divlayout" cdkDrag> {{item.name}} </div > </div>
代码显示的是启用拖放所需的所有属性。当您在浏览器中打开时,它允许您拖动项目。它不会把它放在列表中,当您离开鼠标指针时,它会保持不变。
在这里,它允许从列表中拖动项目,但是一旦您离开鼠标指针,它将会移动并停留在相同的位置。要添加拖放功能,我们需要在app.component.ts中添加事件onDrop,如下所示
首先,我们必须导入dragdrap cdk模块,如下所示。
import {CdkDragDrop, moveItemInArray, transferArrayItem} from '@angular/cdk/drag-drop';
以下是app.component.ts中的完整代码。
import { Component } from '@angular/core'; import { MyserviceService } from './myservice.service'; import {CdkDragDrop, moveItemInArray, transferArrayItem} from '@angular/cdk/drag-drop'; @Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'] }) export class AppComponent { title = 'Angular 7 Project!'; public personaldetails = []; constructor(private myservice: MyserviceService) {} ngOnInit() { this.myservice.getData().subscribe((data) => { this.personaldetails = Array.from(Object.keys(data), k=>data[k]); console.log(this.personaldetails); }); } onDrop(event: CdkDragDrop<string[]>) { if (event.previousContainer === event.container) { moveItemInArray(event.container.data, event.previousIndex, event.currentIndex); } else { transferArrayItem(event.previousContainer.data, event.container.data, event.previousIndex, event.currentIndex); } } }
onDrop函数负责将拖动的项目放到所需的位置。
它利用了我们从cdk dragdrop模块导入的moveItemInArray和transferArrayItem。
现在让我们在浏览器中再次查看演示
现在,你可以将项目拖放到如上所示的所需位置。该功能工作非常平滑,没有任何闪烁问题,可以在您的应用程序中随时随地使用。