Angular7 Drag and Drop

完整代码在最后，下面讲解以此代码为例

1.环境配置

1.1 安装@angular/material、@angular/cdk

cnpm install --save @angular/material @angular/cdk

1.2 app.modules.ts导入

import { DragDropModule } from '@angular/cdk/drag-drop';

imports: [

...

DragDropModule

]

2.功能实现

2.1 拖拽

html编辑如下代码即可：

<div cdkDrag class="drag-box"
drag me
</div>

2.2 排序

html:

<h3>列表排序</h3>
<div class="box-list" cdkDropList (cdkDropListDropped)="drop($event)">
    <div class="drag-box" *ngFor="let customer of customers" cdkDrag>
        {{customer.name}}
    </div>
</div>

　　

　ts:

import { ...CdkDragDrop, moveItemInArray } from '@angular/cdk/drag-drop';

customers = [
{ name: 'Adam', age: 23 },
{ name: 'Jack', age: 27 },
{ name: 'Katherin', age: 26 },
{ name: 'John', age: 30 },
{ name: 'Watson', age: 42 },
];

drop(event: CdkDragDrop<string[]>) {
    console.log('列表排序：', event, this.customers);
    moveItemInArray(this.customers, event.previousIndex, event.currentIndex);
}

　执行如下操作：

打印结果：

2.3 横向排序

html:

<h3>横向排序</h3>
<div class="box-list-horizontal" cdkDropList cdkDropListOrientation="horizontal"
(cdkDropListDropped)="drop($event)">
    <div class="drag-box" *ngFor="let customer of customers" cdkDrag>
        {{customer.name}}
    </div>
</div>

2.4 添加动画效果

　　为了设置动画，我们定义了一个以transform属性为目标的转换。拖放CDK支持动画：

--对列表中的元素进行拖动排序时的动画=> .cdk-drag

.cdk-drag {
    transition: transform 100ms ease;
}

　

--从动画的位置到最终把它放在列表的位置上时的动画=> .cdk-drag-animating

.cdk-drag-animating {
    transition: transform 300ms ease;
}

2.5 占位符元素 placeholder

默认占位符

使用.cdk-drag-placeholder来显示占位符元素，而不是实际的元素，因为它是在cdkDropList中拖动的。默认情况下，这看起来与正在排序的元素完全相同。

.cdk-drag-placeholder {
    background: #ccc;
    border: dotted 1px #999;
    transition: transform 500ms ease;
}

　拖拽时效果如下图：

自定义占位符

使用*cdkDragPlaceholder指令，我们可以用一个自定义的占位符来代替默认的占位符

html:

<div class="box-list customph" cdkDropList (cdkDropListDropped)="drop($event)">
    <div class="drag-box dragList" *ngFor="let customer of customers" cdkDrag >
        <div class="box-custom-placeholder" *cdkDragPlaceholder></div>
        {{customer.name}}
    </div>
</div>

　css:

// 自定义占位符
.customph{
    .box-custom-placeholder {
        height: 28px;
        width: 100px;
        background: #fff;
        border: dotted 1px #0084ff;
        transition: transform 200ms ease;
    }

    &.box-list.cdk-drop-list-dragging .drag-box:not(.cdk-drag-placeholder) {
        transition: transform 500ms ease;
    }
}

　　

2.6 预览

当提取并拖动cdkDrag元素时，可以看到预览元素。默认情况下，预览元素看起来与被拖动的元素完全相同。

使用.cdk-drag-preview来定义预览CSS:

// 预览
.cdk-drag-preview {
    height: 28px;
    width: 100px;
    box-shadow: 0 3px 3px -3px #0084ff;
}

我们还需要使用*cdkDragPreview提供一个自定义模板:

<div cdkDropList class="box-list" (cdkDropListDropped)="drop($event)">
  <div class="drag-box dragList" *ngFor="let customer of customers" cdkDrag>
    {{customer.name}}
    <p *cdkDragPreview>Age: {{customer.age}}</p>
  </div>
</div>

　

2.7 多个列表之间拖拽

我们可以使用cdkDropListConnectedTo属性将一个或多个cdkDropList连接到一起。然后设置cdkDropListData和cdkDragData，将数据与cdkDropList和cdkDrag关联起来。

html:

<div class="box-list" cdkDropList #inactiveList="cdkDropList" id="Inactive Customers"
     [cdkDropListData]="inactiveCustomers" [cdkDropListConnectedTo]="[activeList]"
     (cdkDropListDropped)="drop1($event)">
    <div class="drag-box dragList"
         [cdkDragData]="customer"
         *ngFor="let customer of inactiveCustomers"
         cdkDrag>
        {{customer.name}}
    </div>
</div>
<div class="box-list" cdkDropList #activeList="cdkDropList" id="Active Customers"
     [cdkDropListData]="activeCustomers" [cdkDropListConnectedTo]="[inactiveList]"
     (cdkDropListDropped)="drop1($event)">
    <div class="drag-box dragList"
         [cdkDragData]="customer"
         *ngFor="let customer of activeCustomers"
         cdkDrag>
        {{customer.name}}
    </div>
</div>

　ts:

import { ...transferArrayItem } from '@angular/cdk/drag-drop';

  inactiveCustomers = [
    {name: 'Jack', age: 18},
    {name: 'Katherin', age: 16},
    {name: 'Adam', age: 36}
  ];

  activeCustomers = [
    {name: 'John', age: 10},
    {name: 'Watson', age: 24}
  ];

  drop1(event: CdkDragDrop<string[]>) {
    console.log('拖拽事件：event', event);
    if (event.previousContainer === event.container) {
      console.log('拖拽事件',
        `> 拖 '${event.item.data}' 到 '${event.container.id}'`);
      moveItemInArray(event.container.data, event.previousIndex, event.currentIndex);
    } else {
      console.log('拖拽事件',
        `> 拖 '${event.item.data}' 到 '${event.container.id}'`);
      transferArrayItem(
        event.previousContainer.data, event.container.data,
        event.previousIndex, event.currentIndex);
    }
  }

　执行如下操作：

打印结果：

CdkDropListGroup

CdkDropListGroup指令的范围比CdkDropList要大一级。CdkDropListGroup可以包含多个CdkDropList。而且当CdkDropListGroup包含多个CdkDropList的时候，这些CdkDropList直接是相互connect的(CdkDropList就不用去写cdkDropListConnectedTo属性了)。

<div cdkDropListGroup>
    <div class="box-list" cdkDropList id="Inactive Customers"
         [cdkDropListData]="inactiveCustomers"
         (cdkDropListDropped)="drop1($event)">
        <div class="drag-box dragList" [cdkDragData]="customer"
             *ngFor="let customer of inactiveCustomers" cdkDrag>
            {{customer.name}}
        </div>
    </div>
    <div class="box-list" cdkDropList id="Active Customers"
         [cdkDropListData]="activeCustomers"
         (cdkDropListDropped)="drop1($event)">
        <div class="drag-box dragList"
             [cdkDragData]="customer"
             *ngFor="let customer of activeCustomers"
             cdkDrag>
            {{customer.name}}
        </div>
    </div>
</div>

　

2.8 事件监听

Drag Event Handlers

– cdkDragStarted: 当用户开始拖动时发出。

– cdkDragEnded: 当用户停止拖动时发出。

– cdkDragEntered: 将item移动到新容器中时发出。

– cdkDragExited: 将item移出当前容器时发出。

Drop Event Handlers

– cdkDropListDropped: emits when an item was dropped inside the container.

– cdkDropListEntered: emits when a new item is dragged into this container.

– cdkDropListExited: emits when an item is dragged from this container into another container.

cdkDragStarted、cdkDragEnded、cdkDragMoved

html:

<h3>事件监听</h3>
<div cdkDrag class="drag-box"
  (cdkDragStarted)="dragStarted($event)"
  (cdkDragEnded)="dragEnded($event)"
  (cdkDragMoved)="dragMoved($event)"
>
  drag me
</div>
<p>{{state}} {{position}}</p>

　ts:

import { CdkDragEnd, CdkDragStart, CdkDragMove... } from '@angular/cdk/drag-drop';

  dragStarted(event: CdkDragStart) {
    this.state = '拖拽开始';
    console.log('拖拽开始');
  }

  dragEnded(event: CdkDragEnd) {
    this.state = '拖拽结束';
    console.log('拖拽结束');
  }

  dragMoved(event: CdkDragMove) {
    console.log('dragMoved');
    this.position = `> Position X: ${event.pointerPosition.x} - Y: ${event.pointerPosition.y}`;
  }

　

cdkDropListEntered、cdkDropListExited、cdkDragEntered、cdkDragExited

　html:

<div class="box-list" cdkDropList #inactiveList="cdkDropList" id="Inactive Customers"
     [cdkDropListData]="inactiveCustomers" [cdkDropListConnectedTo]="[activeList]"
     (cdkDropListDropped)="drop1($event)"
     (cdkDropListEntered)="dropListEntered($event)" (cdkDropListExited)="dropListExited($event)">
    <div class="drag-box dragList" [cdkDragData]="customer"
         (cdkDragEntered)="dragEntered($event)" (cdkDragExited)="dragExited($event)"
         *ngFor="let customer of inactiveCustomers"
         cdkDrag>
        {{customer}}
    </div>
</div>
<div class="box-list" cdkDropList #activeList="cdkDropList" id="Active Customers"
     [cdkDropListData]="activeCustomers" [cdkDropListConnectedTo]="[inactiveList]"
     (cdkDropListDropped)="drop1($event)">
    <div class="drag-box dragList"
         [cdkDragData]="customer"
         *ngFor="let customer of activeCustomers"
         cdkDrag>
        {{customer}}
    </div>
</div>

　ts:

import { ...CdkDragEnter, CdkDragExit} from '@angular/cdk/drag-drop';

  dragEntered(event: CdkDragEnter) {
    console.log(`drag:把 '${event.item.data}' 拖进 '${event.container.id}' `);
  }

  dragExited(event: CdkDragExit) {
    console.log(`drag:把 '${event.item.data}' 从 '${event.container.id}' 中拖出 `);
  }

  dropListEntered(event: CdkDragEnter) {
    console.log(`drop:'${event.container.id}' 中拖进了 '${event.item.data}'`);
  }

  dropListExited(event: CdkDragExit) {
    console.log(`drop：从 '${event.container.id}' 中拖出 '${event.item.data}'`);
  }

执行如下操作

打印结果：

再執行如下操作：

打印结果：

cdkDropListSorted

拖拽过程中交换item的时候回调

<div class="box-list" cdkDropList #activeList="cdkDropList" id="Active Customers"
     [cdkDropListData]="activeCustomers" [cdkDropListConnectedTo]="[inactiveList]"
     (cdkDropListDropped)="drop1($event)"
     (cdkDropListSorted)="dropListSorted($event)">
    <div class="drag-box dragList"
         [cdkDragData]="customer"
         *ngFor="let customer of activeCustomers"
         cdkDrag>
        {{customer.name}}
    </div>
</div>

　ts:

  dropListSorted(event: CdkDropList) {
    console.log('Sorted:', event);
  }

　　

2.9 属性

cdkDropListEnterPredicate

enterPredicate: (drag: CdkDrag, drop: CdkDropList) => boolean

指定哪些item是可以拖拽到当前容器

html:

<div class="box-list" cdkDropList #activeList="cdkDropList" id="Active Customers"
     [cdkDropListData]="activeCustomers" [cdkDropListConnectedTo]="[inactiveList]"
     (cdkDropListDropped)="drop1($event)" [cdkDropListEnterPredicate]="predicate">
    <div class="drag-box dragList"
         [cdkDragData]="customer"
         *ngFor="let customer of activeCustomers"
         cdkDrag>
        {{customer.name}}
    </div>
</div>

　ts:

import { ...CdkDrag, CdkDropList } from '@angular/cdk/drag-drop';

predicate(drag: CdkDrag, drop: CdkDropList) {
    console.log('predicate:', drag, drop);
    return drag.data.age >= 18;
}

　　

CdkDrag属性：

CdkDropList属性

代码：

html:

<div class="drag-box" cdkDrag>
  drag me
</div>

<h3>锁定方向</h3>
<div class="drag-box" cdkDragLockAxis="y" cdkDrag>
  only up/down
</div>
<div class="drag-box" cdkDragLockAxis="x" cdkDrag>
  only left/right
</div>

<h3>事件监听</h3>
<div cdkDrag class="drag-box"
  (cdkDragStarted)="dragStarted($event)"
  (cdkDragEnded)="dragEnded($event)"
  (cdkDragMoved)="dragMoved($event)"
>
  drag me
</div>
<p>{{state}} {{position}}</p>

<h3>拖拽handler</h3>
<div class="drag-box-with-handler drag-box" cdkDrag>
  <div class="box-handler" cdkDragHandle>
    点我拖拽
  </div>
</div>

<h3>列表排序</h3>
<div class="box-list" cdkDropList (cdkDropListDropped)="drop($event)">
  <div class="drag-box dragList" *ngFor="let customer of customers" cdkDrag>
    {{customer.name}}
  </div>
</div>

<h3>横向排序</h3>
<div class="box-list-horizontal" cdkDropList cdkDropListOrientation="horizontal"
  (cdkDropListDropped)="drop($event)">
  <div class="drag-box dragListH" *ngFor="let customer of customers" cdkDrag>
    {{customer.name}}
  </div>
</div>

<h3>placeholder 默认占位符元素</h3>
<div>使用.cdk-drag-placeholder来显示占位符元素，而不是实际的元素，
  因为它是在cdkDropList中拖动的。默认情况下，占位符元素看起来与正在排序的元素完全相同。</div>
<div class="box-list defplaceh" cdkDropList (cdkDropListDropped)="drop($event)">
  <div class="drag-box dragList" *ngFor="let customer of customers" cdkDrag>
    {{customer.name}}
  </div>
</div>

<h3>placeholder 自定义占位符元素</h3>
<div>使用*cdkDragPlaceholder指令，我们可以用一个自定义的占位符来代替默认的占位符</div>
<div class="box-list customph"  cdkDropList (cdkDropListDropped)="drop($event)">
  <div class="drag-box dragList" *ngFor="let customer of customers" cdkDrag >
      <div class="box-custom-placeholder" *cdkDragPlaceholder></div>
    {{customer.name}}
  </div>
</div>

<h3>预览 Preview</h3>
<div>当提取并拖动cdkDrag元素时，可以看到预览元素。默认情况下，
  预览元素看起来与被拖动的元素完全相同。</div>
<div cdkDropList class="box-list" (cdkDropListDropped)="drop($event)">
  <div class="drag-box dragList" *ngFor="let customer of customers" cdkDrag>
    {{customer.name}}
    <p *cdkDragPreview>Age: {{customer.age}}</p>
  </div>
</div>

<h3>两个列表间拖放</h3>
<div class="twoList">
  <div class="box-list" cdkDropList #inactiveList="cdkDropList" id = "Inactive Customers"
    [cdkDropListData]="inactiveCustomers" [cdkDropListConnectedTo]="[activeList]"
    (cdkDropListDropped)="drop1($event)"
    (cdkDropListEntered)="dropListEntered($event)" (cdkDropListExited)="dropListExited($event)"
    [cdkDropListEnterPredicate]="predicate"
    >
    <div class="drag-box  dragList" [cdkDragData]="customer"
    (cdkDragEntered)="dragEntered($event)" (cdkDragExited)="dragExited($event)"
      *ngFor="let customer of inactiveCustomers;isLast as last"
      cdkDrag>
      {{customer.name}}
    </div>
  </div>
  <div class="box-list" cdkDropList #activeList="cdkDropList" id = "Active Customers"
    [cdkDropListData]="activeCustomers" [cdkDropListConnectedTo]="[inactiveList]"
    (cdkDropListDropped)="drop1($event)" [cdkDropListEnterPredicate]="predicate"
    (cdkDropListSorted)="dropListSorted($event)"
    >
    <div
      class="drag-box  dragList"
      [cdkDragData]="customer"
      *ngFor="let customer of activeCustomers"
      cdkDrag>
      {{customer.name}}
    </div>
  </div>
</div>

<!-- <h3>两个列表间拖放 cdkDropListGroup</h3>
<div class="twoList" cdkDropListGroup>
  <div class="box-list" cdkDropList  id = "Inactive Customers"
    [cdkDropListData]="inactiveCustomers"
    (cdkDropListDropped)="drop1($event)">
    <div class="drag-box  dragList" [cdkDragData]="customer"
      *ngFor="let customer of inactiveCustomers"  cdkDrag>
      {{customer.name}}
    </div>
  </div>
  <div class="box-list" cdkDropList  id = "Active Customers"
    [cdkDropListData]="activeCustomers"
    (cdkDropListDropped)="drop1($event)">
    <div
      class="drag-box  dragList"
      [cdkDragData]="customer"
      *ngFor="let customer of activeCustomers"
      cdkDrag>
      {{customer.name}}
    </div>
  </div>
</div> -->

　ts:

import { Component, OnInit } from '@angular/core';
import { CdkDragEnd, CdkDragStart, CdkDragMove,
  CdkDragDrop, CdkDragEnter, CdkDragExit, moveItemInArray,
  transferArrayItem, CdkDrag, CdkDropList } from '@angular/cdk/drag-drop';

@Component({
  selector: 'app-drag-drop',
  templateUrl: './drag-drop.component.html',
  styleUrls: ['./drag-drop.component.scss']
})
export class DragDropComponent implements OnInit {
  state = '';
  position = '';
  customers = [
    { name: 'Adam', age: 23 },
    { name: 'Jack', age: 27 },
    { name: 'Katherin', age: 26 },
    { name: 'John', age: 30 },
    { name: 'Watson', age: 42 },
  ];
  inactiveCustomers = [
    {name: 'Jack', age: 18},
    {name: 'Katherin', age: 16},
    {name: 'Adam', age: 36}
  ];

  activeCustomers = [
    {name: 'John', age: 10},
    {name: 'Watson', age: 24}
  ];

  constructor() { }

  ngOnInit() {
  }

  dragStarted(event: CdkDragStart) {
    this.state = '拖拽开始';
    console.log('拖拽开始');
  }

  dragEnded(event: CdkDragEnd) {
    this.state = '拖拽结束';
    console.log('拖拽结束');
  }

  dragMoved(event: CdkDragMove) {
    console.log('dragMoved');
    this.position = `> Position X: ${event.pointerPosition.x} - Y: ${event.pointerPosition.y}`;
  }

  dragEntered(event: CdkDragEnter) {
    console.log(`drag:把 '${event.item.data}' 拖进 '${event.container.id}' `);
  }

  dragExited(event: CdkDragExit) {
    console.log(`drag:把 '${event.item.data}' 从 '${event.container.id}' 中拖出 `);
  }

  dropListEntered(event: CdkDragEnter) {
    console.log(`drop:'${event.container.id}' 中拖进了 '${event.item.data}'`);
  }

  dropListExited(event: CdkDragExit) {
    console.log(`drop：从 '${event.container.id}' 中拖出 '${event.item.data}'`);
  }

  drop(event: CdkDragDrop<string[]>) {
    console.log('列表排序：', event, this.customers);
    moveItemInArray(this.customers, event.previousIndex, event.currentIndex);
  }

  drop1(event: CdkDragDrop<string[]>) {
    console.log('拖拽事件：event', event);
    if (event.previousContainer === event.container) {
      console.log('拖拽事件',
        `> 拖 '${event.item.data}' 到 '${event.container.id}'`);
      moveItemInArray(event.container.data, event.previousIndex, event.currentIndex);
    } else {
      console.log('拖拽事件',
        `> 拖 '${event.item.data}' 到 '${event.container.id}'`);
      transferArrayItem(
        event.previousContainer.data, event.container.data,
        event.previousIndex, event.currentIndex);
    }
  }

  predicate(drag: CdkDrag, drop: CdkDropList) {
    console.log('predicate:', drag, drop);
    return drag.data.age >= 18;
  }

  dropListSorted(event: CdkDropList) {
    console.log('Sorted:', event);
  }

}

　app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { ScrollingModule } from '@angular/cdk/scrolling';
import { MatCardModule } from '@angular/material';
import { DragDropModule } from '@angular/cdk/drag-drop';
// import { VIEWPORT_RULER_PROVIDER } from '@angular/cdk/scrolling';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { VirtualScrollComponent } from './virtual-scroll/virtual-scroll.component';
import { DragDropComponent } from './drag-drop/drag-drop.component';

@NgModule({
  declarations: [
    AppComponent,
    VirtualScrollComponent,
    DragDropComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    ScrollingModule,
    MatCardModule,
    DragDropModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

css:

.drag-box{
    height: 100px;
    width: 100px;
    border: 1px solid #000;
}
.box-handler{
    width: 100%;
    height: 20px;
    background: #ccc;
}
.dragList{
    height: 28px;
    margin: 5px 0;
}
.dragListH{
    display: inline-block;
    margin: 0 5px;
    height: 28px;
    width: 55px;
}
// 动画效果
// .cdk-drag {
//     transition: transform 100ms ease;
// }

.cdk-drag-animating {
    transition: transform 300ms ease;
}
// 占位符 默认 placeholder
.defplaceh .cdk-drag-placeholder {
    background: #ccc;
    border: dotted 1px #999;
    transition: transform 500ms ease;
}

// 自定义占位符
.customph{
    .box-custom-placeholder {
        height: 28px;
        width: 100px;
        background: #fff;
        border: dotted 1px #0084ff;
        transition: transform 200ms ease;
    }

    &.box-list.cdk-drop-list-dragging .drag-box:not(.cdk-drag-placeholder) {
        transition: transform 500ms ease;
    }
}

// 预览
.cdk-drag-preview {
    height: 28px;
    width: 100px;
    box-shadow: 0 3px 3px -3px #0084ff;
}

.twoList{
    overflow: hidden;
    >div{
        float: left;
        margin: 10px;
    }
}