Method startDrag

packages/fairygui/src/core/DragDropManager.ts:89–103

* Start a drag operation * 开始拖拽操作 * * @param source - Source object initiating drag | 发起拖拽的源对象 * @param icon - Icon URL for drag agent | 拖拽代理的图标 URL * @param sourceData - Data to carry during drag | 拖拽期间携带的数据 * @param touchId - Touch point ID for multi-touch | 多点触控的触摸点

(source: GObject, icon: string, sourceData?: any, touchId?: number)

     * @param touchId - Touch point ID for multi-touch | 多点触控的触摸点 ID
     */
    public startDrag(source: GObject, icon: string, sourceData?: any, touchId?: number): void {
        if (this._agent.parent) {
            return;
        }

        this._sourceData = sourceData;
        this._agent.url = icon;

        GRoot.inst.addChild(this._agent);

        const stage = Stage.inst;
        const pt = GRoot.inst.globalToLocal(stage.mouseX, stage.mouseY);
        this._agent.setXY(pt.x, pt.y);
        this._agent.startDrag(touchId);
    }

    /**
     * Cancel current drag operation