java - 为什么这个GWT对话框不以两个按钮为中心？

我希望setHorizo​​ntalAlignment将我的两个按钮从左侧移到中间。知道为什么这不起作用吗？所有相关代码在下面，非常简单。

public void onClick(ClickEvent event) {
            final DialogBox deleteDialog = new DialogBox();
            deleteDialog.setModal(false);
            deleteDialog.setGlassEnabled(true);

            HorizontalPanel buttonPane = new HorizontalPanel();
            buttonPane.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_RIGHT);

            buttonPane.add(deleteDialogOKButton);
            buttonPane.add(deleteDialogCancelButton);

            deleteDialog.center();

            deleteDialog.add(buttonPane);
            deleteDialog.setText("Delete this Station?");

            deleteDialogOKButton.addClickHandler(new ClickHandler() {
                public void onClick(ClickEvent event) {
                    stationService.deleteStation(station, new DeleteStationCallback());
                    deleteDialog.hide();
                }});

            deleteDialogCancelButton.addClickHandler(new ClickHandler() {
                public void onClick(ClickEvent event) {
                    deleteDialog.hide();
                }});

            deleteDialog.show();
            //stationService.deleteStation(station, new DeleteStationCallback());
        }
    }

最佳答案

当您不对水平面板赋予任何宽度时，它将占用其内容宽度的总和。因此，HasHorizontalAlignment.ALIGN_RIGHT，HasHorizontalAlignment.ALIGN_LEFT或任何其他对齐方式对于其在给定区域中的拟合都无关紧要。尝试设置以下内容，

buttonPane.setwidth(100%);
buttonPane.setHorizontalAlignment(HasHorizontalAlignment.ALIGN_CENTRE);

如果这也行不通，则必须使用API​​设置单元格对齐

setCellHorizontalAlignment(Widget w,HasHorizontalAlignment.HorizontalAlignmentConstant align);