JavaFX - 拖放 TableCell

Posted 2023-02-27

【中文标题】JavaFX - 拖放 TableCell

【英文标题】：JavaFX - Drag and Drop TableCell

【发布时间】：2016-06-10 06:05:36

【问题描述】：

我有一个包含单元格的 TableView。我的表格像坐标系一样工作，而不像通常的表格。 Click here for more about this.

现在，我需要将一个单元格拖放到另一个单元格（移动）。

这是我的拖放代码：

tableView.setOnDragDetected(new EventHandler<MouseEvent>() 
        @Override
        public void handle(MouseEvent event) 
            Dragboard db = tableView.startDragAndDrop(TransferMode.MOVE);
            ClipboardContent content = new ClipboardContent();

            int x = tableView.getSelectionModel().getSelectedCells().get(0).getColumn();
            int y = tableView.getSelectionModel().getSelectedCells().get(0).getRow();

            for(Event e:eventList) 
                if(e.getAblaufX() == x && e.getAblaufY() == y) 
                    //System.out.println("Event Abteilung: " + e.getAbteilung());
                    content.put(Config.SERIALIZED_MIME_TYPE, e.getId());
                
            

            db.setContent(content);
            event.consume();
        
    );

    tableView.setOnDragDropped(new EventHandler<DragEvent>() 
        @Override
        public void handle(DragEvent event) 
            System.out.println("Drag Dropped!");

            Dragboard db = event.getDragboard();
             if (db.hasContent(Config.SERIALIZED_MIME_TYPE)) 
                 int draggedEventId = (Integer) db.getContent(Config.SERIALIZED_MIME_TYPE);
                 Event draggedEvent = null;
                 //System.out.println("Dragged Event ID: " + draggedEventId);
                 for(Event e:eventList) 
                     if(e.getId() == draggedEventId) 
                         draggedEvent = e;
                         eventMap.get(e).setAblaufX(ablaufX); // <-- HERE I NEED CELL INDEX
                         eventMap.get(e).setAblaufY(ablaufY); // <-- HERE I NEED ROW INDEX
                         //eventMap.put(new TablePos(draggedEvent.getAblaufX(), draggedEvent.getAblaufY()), draggedEvent);
                     
                 
                 if(draggedEvent != null) 
                     event.setDropCompleted(true);
                     event.consume();
                     System.out.println(draggedEvent.getText());
                 
             
        
    );

    tableView.setOnDragOver(new EventHandler <DragEvent>() 
        public void handle(DragEvent event) 
            event.acceptTransferModes(TransferMode.ANY);
            event.consume();
        
    );

我用“// <-- HERE I NEED CELL INDEX”和“// <-- HERE I NEED ROW INDEX”评论了这些棘手的行

在这些行中，我需要删除单元格（新单元格）的 columnIndex 和 rowIndex

【问题讨论】：

也许我没理解，但你为什么不在拖动检测函数之外声明你的 int x 和 y 变量，并且只在检测到拖动时设置它，然后你可以在你的拖放函数中获得当前值

以及如何获得要放置的单元格的坐标（columnIndex 和 rowIndex）？

【参考方案1】：

您需要将setOnDragDropped 添加到表格单元格中，而不是将它们添加到整个TableView 中。下面是关于如何获取单元格的行和列索引的 MCVE。 MCVE 本身除了显示如何获取单元格的行和列索引之外没有其他用处。如果您需要任何进一步的帮助，请告诉我。

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class MCVE extends Application 

    @Override
    public void start(Stage stage) 
        TableView<ObservableList<String>> table = new TableView<ObservableList<String>>();
        table.getSelectionModel().setCellSelectionEnabled(true);

        TableColumn<ObservableList<String>, String> col1 = new TableColumn<ObservableList<String>, String>();
        TableColumn<ObservableList<String>, String> col2 = new TableColumn<ObservableList<String>, String>();

        ObservableList<TableColumn<ObservableList<String>, String>> columns = FXCollections.observableArrayList(col1,
                col2);

        table.getColumns().addAll(columns);

        // For each column we set a cellFactory and a cellValueFactory.
        for (TableColumn<ObservableList<String>, String> col : columns) 
            col.setCellValueFactory(e -> new SimpleStringProperty("1"));

            // We need to set the cell factory so that we can create a cell and manipulate its behavior.
            col.setCellFactory(e -> 
                TableCell<ObservableList<String>, String> cell = new TableCell<ObservableList<String>, String>() 
                    @Override
                    public void updateItem(String item, boolean empty) 
                        // Make sure you call super.updateItem, or you might get really weird bugs.
                        super.updateItem(item, empty);
                        if (item == null || empty) 
                            setText(null);
                            setGraphic(null);
                         else 
                            setText(item);
                            setGraphic(null);
                        
                    
                ;

                // HERE IS HOW TO GET THE ROW AND CELL INDEX
                cell.setOnDragDetected(eh -> 
                    // Get the row index of this cell
                    int rowIndex = cell.getIndex();
                    System.out.println("Cell row index: " + rowIndex);

                    // Get the column index of this cell.
                    int columnIndex = cell.getTableView().getColumns().indexOf(cell.getTableColumn());
                    System.out.println("Cell column index: " + columnIndex);
                );

                return cell;
            );
        

        ObservableList<ObservableList<String>> items = FXCollections.observableArrayList(
                FXCollections.observableArrayList("1", "2"), FXCollections.observableArrayList("1", "2"));

        table.setItems(items);

        BorderPane view = new BorderPane();
        view.setCenter(table);

        stage.setScene(new Scene(view));
        stage.show();
    

    public static void main(String[] args) 
        launch();
    

【参考方案2】：

您可以使用Event 的pickResult 获取当前单元格来访问TableCell 并使用它来获取坐标：

private static TableCell getCell(Node node) 
    // traverse to parent until TableCell is reached
    // or it's clear there's no TableCell in the hierarchy above node (root visited)
    while (node != null && !(node instanceof TableCell)) 
        node = node.getParent();
    

    return (TableCell) node;

TableCell targetCell = getCell(event.getPickResult().getIntersectedNode());
if (targetCell != null) 
    int rowIndex = targetCell.getTableRow().getIndex();
    int columnIndex = columnToIndex(targetCell.getTableColumn());
    ...