如何通过拖放交换jtable中单元格的值

问题描述

我想在同一列中将我的表的数据从一个表交换到另一个表(注意:我只有两列).

I would like to swap the data of my table from one table to another IN THE SAME COLUMN (Note: I have only two columns).

我的问题是我无法交换值.另外，我希望仅在同一列上启用交换，否则，表值将重置为其原始值.

My problem is I cannot swap the value. Also, I want the swapping to be enabled only on the same column, otherwise, the table values will reset to its original values.

这是我的代码:

    JTable table_1 = new JTable(model);
table_1.setPreferredScrollableViewportSize(new Dimension(300, 120));
table_1.setDragEnabled(true);  
table_1.setDropMode(DropMode.USE_SELECTION);  
table_1.setTransferHandler(new TransferHelper()); 
table_1.setRowSelectionAllowed(false);
table_1.setCellSelectionEnabled(true);

我的 TransferHelper 类:

My TransferHelper Class:

class TransferHelper extends TransferHandler {  

    private static final long serialVersionUID = 1L;

    public TransferHelper() {  
    }  

    @Override  
    public int getSourceActions(JComponent c) {  
        return MOVE;  
    }  

    @Override  
    protected Transferable createTransferable(JComponent source) {  
        String data = (String) ((JTable) source).getModel().getValueAt(((JTable) source).getSelectedRow(), ((JTable) source).getSelectedColumn());
        return new StringSelection(data);  
    }  

    @Override  
    protected void exportDone(JComponent source, Transferable data, int action) {  
        ((JTable) source).getModel().setValueAt("", ((JTable) source).getSelectedRow(), ((JTable) source).getSelectedColumn());  
    }  

    @Override  
    public boolean canImport(TransferSupport support) {  
        return true;  
    }  

    @Override  
    public boolean importData(TransferSupport support) {  
        JTable jt = (JTable) support.getComponent();  
        try {
            jt.setValueAt(support.getTransferable().getTransferData(DataFlavor.stringFlavor), jt.getSelectedRow(), jt.getSelectedColumn());  
        } catch (UnsupportedFlavorException ex) {  

        } catch (IOException ex) {  

        }  
        return super.importData(support);  
    }  
}  

推荐答案

拖放不是一个简单的过程，它相当复杂和复杂.这种复杂性带来了灵活性.

Drag and drop is not a simple process, it's quite complex and involved. With this complexity comes flexibility.

以这种方式交换值与移动"本身不同.移动某物时，您从源中取出它并将其放置在目标中，这里我们在源和目标之间交换值，这意味着我们需要比通常通过 API 获得的更多信息.

Swapping values in this way isn't the same as "moving" per se. When moving something, you take it from the source and place it in the target, here we are swapping values between the source and target, this means we need more information than is generally available via the API.

首先，您将需要一个自定义类来保存要导出的数据，因为我们正在移动数据，这将需要一些额外的信息，特别是源组件...

First of all, you're going to need a custom class to hold the data to be exported, because we're moving data, this is going to require some additional information, in particular, the source component...

以下只是一个简单的包装器.我们可以完全导出 JTable，但我想演示一下拖放的基本概念...

The following is just a simple wrapper. We could export the JTable entirely, but I wanted to demonstrate a basic concept of drag-n-drop...

import javax.swing.JTable;

public class CellData {
    private JTable table;

    public CellData(JTable table) {
        this.table = table;
    }

    public int getColumn() {
        return table.getSelectedColumn();
    }

    public String getValue() {
        int row = table.getSelectedRow();
        int col = table.getSelectedColumn();
        return (String) table.getValueAt(row, col);
    }

    public JTable getTable() {
        return table;
    }

}

接下来，我们需要一个自定义的Transferable来管理我们的数据...

Next, we need a custom Transferable to manage our data...

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;

public class CellDataTransferable implements Transferable {

    public static final DataFlavor CELL_DATA_FLAVOR = createConstant(CellData.class, "application/x-java-celldata");
    private CellData cellData;

    public CellDataTransferable(CellData cellData) {
        this.cellData = cellData;
    }

    @Override
    public DataFlavor[] getTransferDataFlavors() {
        return new DataFlavor[]{CELL_DATA_FLAVOR};
    }

    @Override
    public boolean isDataFlavorSupported(DataFlavor flavor) {
        boolean supported = false;
        for (DataFlavor available : getTransferDataFlavors()) {
            if (available.equals(flavor)) {
                supported = true;
            }
        }
        return supported;
    }

    @Override
    public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
        return cellData;
    }

    static protected DataFlavor createConstant(Class clazz, String name) {
        try {
            return new DataFlavor(clazz, name);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

}

最后，TransferHandler....

public class TransferHelper extends TransferHandler {

    private static final long serialVersionUID = 1L;

    public TransferHelper() {
    }

    @Override
    public int getSourceActions(JComponent c) {
        return MOVE;
    }

    @Override
    protected Transferable createTransferable(JComponent source) {
        // Create the transferable
        // Because I'm hacking a little, I've included the source table...
        JTable table = (JTable) source;
        return new CellDataTransferable(new CellData(table));
    }

    @Override
    protected void exportDone(JComponent source, Transferable data, int action) {
    }

    @Override
    public boolean canImport(TransferSupport support) {
        // Reject the import by default...
        boolean canImport = false;
        // Can only import into another JTable
        Component comp = support.getComponent();
        if (comp instanceof JTable) {
            JTable table = (JTable) comp;
            // Need the location where the drop might occur
            DropLocation dl = support.getDropLocation();
            Point dp = dl.getDropPoint();
            // Get the column at the drop point
            int dragColumn = table.columnAtPoint(dp);
            try {
                // Get the Transferable, we need to check
                // the constraints
                Transferable t = support.getTransferable();
                CellData cd = (CellData) t.getTransferData(CellDataTransferable.CELL_DATA_FLAVOR);
                // Make sure we're not dropping onto ourselves...
                if (cd.getTable() != table) {
                    // Do the columns match...?
                    if (dragColumn == cd.getColumn()) {
                        canImport = true;
                    }
                }
            } catch (UnsupportedFlavorException | IOException ex) {
                ex.printStackTrace();
            }
        }
        return canImport;
    }

    @Override
    public boolean importData(TransferSupport support) {
        // Import failed for some reason...
        boolean imported = false;
        // Only import into JTables...
        Component comp = support.getComponent();
        if (comp instanceof JTable) {
            JTable target = (JTable) comp;
            // Need to know where we are importing to...
            DropLocation dl = support.getDropLocation();
            Point dp = dl.getDropPoint();
            int dropCol = target.columnAtPoint(dp);
            int dropRow = target.rowAtPoint(dp);
            try {
                // Get the Transferable at the heart of it all
                Transferable t = support.getTransferable();
                CellData cd = (CellData) t.getTransferData(CellDataTransferable.CELL_DATA_FLAVOR);
                if (cd.getTable() != target) {
                    // Make sure the columns match
                    if (dropCol == cd.getColumn()) {
                        // Get the data from the "dropped" table
                        String exportValue = (String) target.getValueAt(dropRow, dropCol);
                        // Get the data from the "dragged" table
                        String importValue = cd.getValue();
                        // This is where we swap the values...
                        // Set the target/dropped tables value
                        target.setValueAt(importValue, dropRow, dropCol);

                        // Set the source/dragged tables values
                        JTable source = cd.getTable();
                        int row = source.getSelectedRow();
                        int col = source.getSelectedColumn();
                        source.setValueAt(exportValue, row, col);

                        imported = true;
                    }
                }
            } catch (UnsupportedFlavorException | IOException ex) {
                ex.printStackTrace();
            }

        }
        return imported;
    }
}

阅读评论:P

最后，一个可运行的例子……

And finally, a runnable example...

import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.DropMode;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.TransferHandler;
import static javax.swing.TransferHandler.MOVE;
import javax.swing.TransferHandler.TransferSupport;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;

public class TableSwap {

    public static void main(String[] args) {
        new TableSwap();
    }

    public TableSwap() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JTable t1 = createTable(0);
                JTable t2 = createTable(20);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new GridLayout(0, 2));
                frame.add(new JScrollPane(t1));
                frame.add(new JScrollPane(t2));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    protected JTable createTable(int startAt) {

        DefaultTableModel model = new DefaultTableModel(0, 2);
        for (int index = 0; index < 10; index++) {
            model.addRow(new Object[]{"0x" + (index + startAt), "1x" + (index + startAt)});
        }

        JTable table = new JTable(model);
        table.setDragEnabled(true);
        table.setDropMode(DropMode.USE_SELECTION);
        table.setTransferHandler(new TransferHelper());
        table.setRowSelectionAllowed(false);
        table.setCellSelectionEnabled(true);

        return table;
    }

}

更新为仅支持单个表格

import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import javax.swing.DropMode;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.TransferHandler;
import static javax.swing.TransferHandler.MOVE;
import javax.swing.TransferHandler.TransferSupport;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;

public class TableSwap {

    public static void main(String[] args) {
        new TableSwap();
    }

    public TableSwap() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JTable t1 = createTable(0);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(t1));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    protected JTable createTable(int startAt) {

        DefaultTableModel model = new DefaultTableModel(0, 2);
        for (int index = 0; index < 10; index++) {
            model.addRow(new Object[]{"0x" + (index + startAt), "1x" + (index + startAt)});
        }

        JTable table = new JTable(model);
        table.setDragEnabled(true);
        table.setDropMode(DropMode.USE_SELECTION);
        table.setTransferHandler(new TransferHelper());
        table.setRowSelectionAllowed(false);
        table.setCellSelectionEnabled(true);

        return table;
    }

    public class CellData {

        private final Object value;
        private final int col;
        private final JTable table;
        private final int row;

        public CellData(JTable source) {
            this.col = source.getSelectedColumn();
            this.row = source.getSelectedRow();
            this.value = source.getValueAt(row, col);
            this.table = source;
        }

        public int getColumn() {
            return col;
        }

        public Object getValue() {
            return value;
        }

        public JTable getTable() {
            return table;
        }

        public boolean swapValuesWith(int targetRow, int targetCol) {

            boolean swapped = false;

            if (targetCol == col) {

                Object exportValue = table.getValueAt(targetRow, targetCol);
                table.setValueAt(value, targetRow, targetCol);
                table.setValueAt(exportValue, row, col);
                swapped = true;

            }

            return swapped;

        }

    }

    public static final DataFlavor CELL_DATA_FLAVOR = createConstant(CellData.class, "application/x-java-celldata");

    public class CellDataTransferable implements Transferable {

        private CellData cellData;

        public CellDataTransferable(CellData cellData) {
            this.cellData = cellData;
        }

        @Override
        public DataFlavor[] getTransferDataFlavors() {
            return new DataFlavor[]{CELL_DATA_FLAVOR};
        }

        @Override
        public boolean isDataFlavorSupported(DataFlavor flavor) {
            boolean supported = false;
            for (DataFlavor available : getTransferDataFlavors()) {
                if (available.equals(flavor)) {
                    supported = true;
                }
            }
            return supported;
        }

        @Override
        public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
            return cellData;
        }

    }

    static protected DataFlavor createConstant(Class clazz, String name) {
        try {
            return new DataFlavor(clazz, name);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public class TransferHelper extends TransferHandler {

        private static final long serialVersionUID = 1L;

        public TransferHelper() {
        }

        @Override
        public int getSourceActions(JComponent c) {
            return MOVE;
        }

        @Override
        protected Transferable createTransferable(JComponent source) {
            // Create the transferable
            JTable table = (JTable) source;
            int row = table.getSelectedRow();
            int col = table.getSelectedColumn();
            Object value = table.getValueAt(row, col);
            return new CellDataTransferable(new CellData(table));
        }

        @Override
        protected void exportDone(JComponent source, Transferable data, int action) {
        }

        @Override
        public boolean canImport(TransferSupport support) {
            // Reject the import by default...
            boolean canImport = false;
            // Can only import into another JTable
            Component comp = support.getComponent();
            if (comp instanceof JTable) {
                JTable target = (JTable) comp;
                // Need the location where the drop might occur
                DropLocation dl = support.getDropLocation();
                Point dp = dl.getDropPoint();
                // Get the column at the drop point
                int dragColumn = target.columnAtPoint(dp);
                try {
                    // Get the Transferable, we need to check
                    // the constraints
                    Transferable t = support.getTransferable();
                    CellData cd = (CellData) t.getTransferData(CELL_DATA_FLAVOR);
                    // Make sure we're not dropping onto ourselves...
                    if (cd.getTable() == target) {
                        // Do the columns match...?
                        if (dragColumn == cd.getColumn()) {
                            canImport = true;
                        }
                    }
                } catch (UnsupportedFlavorException | IOException ex) {
                    ex.printStackTrace();
                }
            }
            return canImport;
        }

        @Override
        public boolean importData(TransferSupport support) {
            // Import failed for some reason...
            boolean imported = false;
            // Only import into JTables...
            Component comp = support.getComponent();
            if (comp instanceof JTable) {
                JTable target = (JTable) comp;
                // Need to know where we are importing to...
                DropLocation dl = support.getDropLocation();
                Point dp = dl.getDropPoint();
                int dropCol = target.columnAtPoint(dp);
                int dropRow = target.rowAtPoint(dp);
                try {
                    // Get the Transferable at the heart of it all
                    Transferable t = support.getTransferable();
                    CellData cd = (CellData) t.getTransferData(CELL_DATA_FLAVOR);
                    if (cd.getTable() == target) {
                        if (cd.swapValuesWith(dropRow, dropCol)) {
                            imported = true;
                        }
                    }
                } catch (UnsupportedFlavorException | IOException ex) {
                    ex.printStackTrace();
                }

            }
            return imported;
        }
    }

}

这篇关于如何通过拖放交换jtable中单元格的值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！