javafx 表格列拖拉

JavaFX “缺少功能調查”中提到的“缺少功能”的第一件事就是能夠自動調整表/樹表中的列大小。 沒錯，沒有公共API是正確的，但是當您密切關注時，您會注意到JavaFX內部一定有執行此操作的代碼，因為用戶可以通過雙擊分隔線自動調整列的大小。在該列與右側的下一列之間。

但是像大多數人一樣，我覺得這對我的代碼還不夠好。 我想要一個FlexGanttFX的API，該API允許用戶自動調整甘特圖內一列或所有列的大小。 因此，我搜索了隱藏在樹表或樹表皮膚某處（實際上不記得在哪里）的代碼，并在我的類中進行了一些較小的修改以重新使用它。

以下是這項工作的結果。 它以TreeTableView而不是TableView為目標，但是使它適用于標準表很簡單。 只需將所有TreeTableColumn出現替換為TableColumn即可 。 請注意，調整所有行的大小可能會對性能產生嚴重影響，因此您可能必須通過maxRows參數來限制要用于計算的行數 。

/*** This method will resize all columns in the tree table view to ensure that* the content of all cells will be completely visible. Note: this is a very* expensive operation and should only be used when the number of rows is* small.** @see #resizeColumn(TreeTableColumn, int)*/public final void resizeColumns() {resizeColumns(-1);}/*** This method will resize all columns in the tree table view to ensure that* the content of all cells will be completely visible. Note: this is a very* expensive operation and should only be used with a small number of rows.** @param maxRows* the maximum number of rows that will be considered for the* width calculations** @see #resizeColumn(TreeTableColumn, int)*/public final void resizeColumns(int maxRows) {for (TreeTableColumn<R, ?> column : getTreeTable().getColumns()) {resizeColumn(column, maxRows);}}/*** This method will resize the given column in the tree table view to ensure* that the content of the column cells will be completely visible. Note:* this is a very expensive operation and should only be used when the* number of rows is small.** @see #resizeColumn(TreeTableColumn, int)*/public final void resizeColumn(TreeTableColumn<R, ?> column) {resizeColumn(column, -1);}/*** This method will resize the given column in the tree table view to ensure* that the content of the column cells will be completely visible. Note:* this is a very expensive operation and should only be used when the* number of rows is small.** @see #resizeColumn(TreeTableColumn, int)*/public final void resizeColumn(TreeTableColumn<R, ?> tc, int maxRows) {final TreeTableColumn col = tc;List<?> items = getItems();if (items == null || items.isEmpty()) {return;}Callback cellFactory = tc.getCellFactory();if (cellFactory == null) {return;}TreeTableCell<R, ?> cell = (TreeTableCell<R, ?>) cellFactory.call(tc);if (cell == null) {return;}// set this property to tell the TableCell we want to know its actual// preferred width, not the width of the associated TableColumnBasecell.getProperties().put("deferToParentPrefWidth", Boolean.TRUE); //$NON-NLS-1$// determine cell paddingdouble padding = 10;Node n = cell.getSkin() == null ? null : cell.getSkin().getNode();if (n instanceof Region) {Region r = (Region) n;padding = r.snappedLeftInset() + r.snappedRightInset();}TreeTableRow<R> treeTableRow = new TreeTableRow<>();treeTableRow.updateTreeTableView(treeTableView);int rows = maxRows == -1 ? items.size(): Math.min(items.size(), maxRows);double maxWidth = 0;for (int row = 0; row < rows; row++) {treeTableRow.updateIndex(row);treeTableRow.updateTreeItem(treeTableView.getTreeItem(row));cell.updateTreeTableColumn(col);cell.updateTreeTableView(treeTableView);cell.updateTreeTableRow(treeTableRow);cell.updateIndex(row);if ((cell.getText() != null && !cell.getText().isEmpty())|| cell.getGraphic() != null) {getChildren().add(cell);cell.impl_processCSS(false);double w = cell.prefWidth(-1);maxWidth = Math.max(maxWidth, w);getChildren().remove(cell);}}// dispose of the cell to prevent it retaining listeners (see RT-31015)cell.updateIndex(-1);// RT-23486double widthMax = maxWidth + padding;if (treeTableView.getColumnResizePolicy() == TreeTableView.CONSTRAINED_RESIZE_POLICY) {widthMax = Math.max(widthMax, tc.getWidth());}tc.impl_setWidth(widthMax);}

翻譯自: https://www.javacodegeeks.com/2015/12/javafx-tip-22-autosize-tree-table-columns.html

javafx 表格列拖拉

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