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javascriptangularangular-materialangular-cdk

Cancel drag on key press Angular cdk Drag and Drop


I´m working in a application implementing the new drag and drop from angular material CDK and i´m trying to cancel the drag event of the element pressing Esc, i mean, i start dragging the element but if i press Esc while i´m dragging the element, it should go back to the position from where i start dragging it, so far i haven´t found a way to do this, does anyone know how can i do this. There nothing in the cdk documentation about this any idea. i try doing something like this.

Template

<div cdkDropList class="example-list" (cdkDropListDropped)="drop($event)">
  <div class="example-box" *ngFor="let movie of movies" (cdkDragEnded)="onDragEnded($event)" cdkDrag>{{movie}}</div>
</div>

Ts component

onDragEnded(event: CdkDragEnd) {
  console.log(event)
  event.source.element.nativeElement.style.transform = 'none';
  const source: any = event.source;
  source._passiveTransform = { x: 0, y: 0 };
}

but no success so far.


Solution

  • I also faced this problem for a long time. Finally I could fix it by dispatching a mouseup event that will act as the user releasing the mouse.

    @HostListener('window:keyup', ['$event'])
    handleKeyboardEvent(event: KeyboardEvent) {
        if (event.key === 'Escape') {
            document.dispatchEvent(new Event('mouseup'));
        }
    }
    

    This is an extremely hacky solution and comes with it's down sides. In fact, you are not cancelling the drag but instead dropping. Meaning that if you are hovering a cdkDropList or one is active it will trigger the cdkDropListDropped emmiter for that list. Something you can easily workaround by adding a flag.

    private _canceledByEsq = false;
    
    @HostListener('window:keyup', ['$event'])
    handleKeyboardEvent(event: KeyboardEvent) {
        if (event.key === 'Escape') {
            this._canceledByEsq = true;
            document.dispatchEvent(new Event('mouseup'));
        }
    }
    
    handleDrop() {
        if (!this._canceledByEsq) {
            // Do my data manipulations
        }
    }
    

    Hope this helps you... :)