GWT Custom DataGrid SelectionHandler未选择子项

Question

最后我运行了一个自定义DataGrid。它与gwt的展示相同。所以我得到了一些子项和一些主题。但现在我想检测ClickEvents。过了一会儿我发现了，我需要一个SelectionHandler。但在实施之后，它只选择了主题。 有没有办法捕捉子项目的选择？

我还通过selectionHandler.setSelected(subitem, true);设置了一个选项并且效果很好，但是如何从userinput / ClickEvent获取我的子项目的选择？

基本代码只是：
selectionModel.addSelectionChangeHandler(new SelectionChangeEvent.Handler() { @Override public void onSelectionChange(final SelectionChangeEvent event) { File selected = ((SingleSelectionModel) selectionModel).getSelectedObject(); if(selected != null){ Window.alert(selected.getFileName()); } } } });

/**
 * Renders the data rows that display each contact in the table.
 */
private class CustomTableBuilder extends AbstractCellTableBuilder<File> {

    private final String childCell = " " + FileTreeViewImpl.this.resources.styles().childCell();
    private final String rowStyle;
    private final String selectedRowStyle;
    private final String cellStyle;
    private final String selectedCellStyle;

    public CustomTableBuilder() {
        super(FileTreeViewImpl.this.fileDataGrid);

        DefaultSelectionEventManager.createCustomManager(new DefaultSelectionEventManager
                .WhitelistEventTranslator<File>(0));

        // Cache styles for faster access.
        com.google.gwt.user.cellview.client.AbstractCellTable.Style style = FileTreeViewImpl.this.fileDataGrid.getResources().style();
        this.rowStyle = style.evenRow();
        this.selectedRowStyle = " " + style.selectedRow();
        this.cellStyle = style.cell() + " " + style.evenRowCell();
        this.selectedCellStyle = " " + style.selectedRowCell();
    }

    @Override
    protected void buildRowImpl(final File rowValue, final int absRowIndex) {
        buildContactRow(rowValue, absRowIndex, false);

        // Display list of files.
        if (FileTreeViewImpl.this.displayFolderContent.contains(rowValue.getFileName())) {
            Set<File> files = FileTreeViewImpl.this.folderMap.get(rowValue.getFileName());
            for (File file : files) {
                buildContactRow(file, absRowIndex, true);
            }
        }
    }


    /**
     * Build a row.
     * 
     * @param rowValue
     *            the file info
     * @param absRowIndex
     *            the absolute row index
     * @param isFriend
     *            true if this is a subrow, false if a top level row
     */
    private void buildContactRow(final File rowValue, final int absRowIndex, final boolean isFriend) {
        // Calculate the row styles.
        SelectionModel<? super File> selectionModel = FileTreeViewImpl.this.fileDataGrid.getSelectionModel();
        boolean isSelected = (selectionModel == null || rowValue == null) ? false : selectionModel.isSelected(rowValue);
        StringBuilder trClasses = new StringBuilder(this.rowStyle);
        if (isSelected) {
            trClasses.append(this.selectedRowStyle);
        }

        // Calculate the cell styles.
        String cellStyles = this.cellStyle;
        if (isSelected) {
            cellStyles += this.selectedCellStyle;
        }
        if (isFriend) {
            cellStyles += this.childCell;
        }

        TableRowBuilder row = startRow();
        row.className(trClasses.toString());

        // Column one to expand the submenu.
        TableCellBuilder td = row.startTD();
        td.style().outlineStyle(OutlineStyle.NONE).endStyle();
        if (!isFriend) {
            renderCell(td, createContext(0), FileTreeViewImpl.this.viewFolderContent, rowValue);
        }
        td.endTD();

        // Filename goes here.
        td = row.startTD();
        td.className(cellStyles);
        td.style().outlineStyle(OutlineStyle.NONE).endStyle();
        if (isFriend) {
            td.text(rowValue.getFileName());
        } else {
            renderCell(td, createContext(1), FileTreeViewImpl.this.nameColumn, rowValue);
        }
        td.endTD();

        // Filesize goes here.
        td = row.startTD();
        td.className(cellStyles);
        td.style().outlineStyle(OutlineStyle.NONE).endStyle();
        if (isFriend) {
            td.text(rowValue.getFileSizeAsString());
        } else {
            renderCell(td, createContext(2), FileTreeViewImpl.this.sizeColumn, rowValue);
        }
        td.endTD();

        // Last Editor goes here.
        td = row.startTD();
        td.className(cellStyles);
        td.style().outlineStyle(OutlineStyle.NONE).endStyle();
        if (isFriend) {
            td.text(rowValue.getLastEditedBy());
        } else {
            renderCell(td, createContext(3), FileTreeViewImpl.this.editedColumn, rowValue);
        }
        td.endTD();

        row.endTR();
    }
}</code>

问候