我想使用 Observable 作为材质拖放的数据源,但我现在正在苦苦挣扎。基本上,我在看板中有一个泳道列表,每个泳道都有一堆我想移动的项目。当我移动一个项目时,我也想更新后端。多人也将更新同一个看板,所以我也想使用 socket.io 来自动移动项目(出于同样的原因,我也在为此苦苦挣扎)
这是模板:
<button mat-raised-button color="primary" (click)="addItem()">Add Item</button>
<button mat-raised-button color="primary" (click)="moveItem()" style="margin-left:10px">Move Item</button>
<div cdkDropListGroup>
<div class="example-container" *ngFor="let lane of swimlanes">
<h2>{{lane.name}}</h2>
<div
cdkDropList
#doneList="cdkDropList"
[cdkDropListData]="lane.array | async"
class="example-list"
(cdkDropListDropped)="drop($event)">
<div class="example-box" *ngFor="let item of lane.array | async" cdkDrag>{{item.name}}</div>
</div>
</div>
</div>
这是组件代码:
import {Component, OnInit} from '@angular/core';
import {CdkDragDrop, moveItemInArray, transferArrayItem} from '@angular/cdk/drag-drop';
import { Subscription, of, Observable } from 'rxjs';
import { map } from 'rxjs/operators';
export interface Swimlane{
name: string;
array: Observable<Task[]>;
}
export interface Task{
name: string;
list: string;
}
/**
* @title Drag&Drop connected sorting
*/
@Component({
selector: 'cdk-drag-drop-connected-sorting-example',
templateUrl: 'cdk-drag-drop-connected-sorting-example.html',
styleUrls: ['cdk-drag-drop-connected-sorting-example.css'],
})
export class CdkDragDropConnectedSortingExample implements OnInit {
//These will eventually come from an API.
items:Task[] = [
{name: "Get to work", list: "To Do"},
{name: "Pick up groceries", list: "To Do"},
{name: "Go home", list: "To Do"},
{name: "Fall asleep", list: "To Do"},
{name: "Get up", list: "Done"},
{name: "Brush teeth", list: "Done"},
{name: "Take a shower", list: "Done"},
{name: "Check e-mail", list: "Done"},
{name: "Walk dog", list: "Done"}
];
swimlanes:Swimlane[] = [];
//Create Observables as the data sources
itemsObservable:Observable<Task[]>;
todo:Observable<Task[]>;
done:Observable<Task[]>;
ngOnInit(): void {
this.itemsObservable = of(this.items);
this.todo = this.itemsObservable.pipe(
map((item:Task[]) => item.filter((item:Task) => item.list === "Done")
));
this.done = this.itemsObservable.pipe(
map((item:Task[]) => item.filter((item:Task) => item.list === "To Do")
));
this.swimlanes.push({name:"To Do", array: this.todo});
this.swimlanes.push({name:"Done", array: this.done});
}
addItem(){
this.items.push({name: "New Item", list: "To Do"});
console.log(this.items.length);
}
moveItem(){
}
drop(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);
}
}
}
这是我尝试使用可观察对象作为数据源的堆栈闪电战。您可以看到它正确加载了通道,但是当您尝试移动其中一个项目时,它会消失。有任何想法吗?
在我的实际应用程序中,我从 API 请求中接收值。所以它会自动作为一个 Observable 进来。然后我闯入一个本地基本数组并取消订阅 Observable。然后我从本地基础数组创建一个新的 Observable 并对本地基础数组进行更改,希望这些更改会反映在拖放中。但这目前不起作用。
很高兴编写我自己的移动功能,但没有反映可观察数据源更改的车道,我无法让它工作。