如何在按下JButton后清除JTable内容？

Question

In my program There is a JTable and 2 Buttons named "Save" and "Refresh". My program overview :

Let, Manually i have entered 10 rows into the JTable. Than i updated these data into database by clicking "Save" button.

Now my point is :

When "Refresh" button will be clicked, All the rows of the JTable should be cleared for next entry.

dataModel = new AbstractTableModel() {
        private String[] columnNames = {"Sl No","Material Code", "Material         Name", "Quntity", "Unit", "Unit/Price","Total Price", "Status" };//new String[9];
        private Object[][] data = new Object[100][9];

          public int getColumnCount() { return columnNames.length; }
          public int getRowCount() { return data.length;}
          public String getColumnName(int col) {
            // TODO Auto-generated method stub
            return columnNames[col];
        }
          public Object getValueAt(int row, int col) {
            // TODO Auto-generated method stub
            return data[row][col];
        }

        @Override
        public void setValueAt(Object aValue, int row, int col) {
            // TODO Auto-generated method stub
            data[row][col] = aValue;
            fireTableCellUpdated(row, col);
        }

        public boolean isCellEditable(int rowIndex, int columnIndex) {
            // TODO Auto-generated method stub
            return true;
        }
        public Class getColumnClass(int col) {
            if((col == 3) || (col == 5) || (col == 6))
                return Double.class;
            //return getValueAt(0, c).getClass();
            return String.class;
        }
      };

create table with abstract datamodel.

    table = new JTable(dataModel);
    JTableHeader header = table.getTableHeader();
    header.setBackground(Color.yellow);
    JScrollPane pane = new JScrollPane(table);
    pane.setPreferredSize(new Dimension(800, 350));
    table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

Add this panel to ContentPane.

   panel.add(pane);
    panel.setBounds(100, 100, 800, 360);
    c.add(panel);

Frame hase a button "Refresh". actionPerformed(ActionEvent e) {} Manually i have entered the data into JTable. Than i updated these data into database by clicking "Save" button.

Now my point is :

When "Refresh" button will be clicked, All the cell of the table should be cleared.

i have implemented TableModeListner as below.

public void tableChanged(TableModelEvent e) {
// TODO Auto-generated method stub
int row = e.getFirstRow();
int column = e.getColumn();

row_sl is intialised with 0.

 if(row_sl >= row){
 if(column == 1){
 String dat = (String) dataModel.getValueAt(row, column);
dataModel.removeTableModelListener(this);

//it fetches database and retribes material name and unit. then set it to respective column.

   mat.getmaterial_name(dat); 
       dataModel.setValueAt(mat.materialname, row, column+1);
dataModel.setValueAt(mat.unit, row, column+3);
//dataModel.setValueAt(dat, 1, 2);
dataModel.addTableModelListener(this);
}
if((column == 5) && (Double)dataModel.getValueAt(row, 3) != null){
    dataModel.removeTableModelListener(this);
    Double d = (Double) dataModel.getValueAt(row, 3);
    d = d * (Double)dataModel.getValueAt(row, column);
    dataModel.setValueAt(d, row, 6);
    dataModel.addTableModelListener(this);
}
if(row == row_sl && column == 7)
    row_sl ++;
}
else
    new error_frame("Complete the row no:"+row_sl);

  public void actionPerformed(ActionEvent e) {
  if(e.getSource() == Refresh){
     dataModel.removeTableModelListener(this);
        for (int i=0;i<=count;i++){
            for(int j=0;j<=7;j++){
                    dataModel.setValueAt(null, i, j);
            }
        }
        dataModel.addTableModelListener(this);
 }
}

When "Refresh" button clicked the method dataModel.setValueAt(null, i, j); is being called. This method triggers TableModeListner event public void tableChanged(TableModelEvent e) .

Hence problem arrises. My requirment is :

When "Refresh button is clicked, all the table cell should be cleared, without affecting my code under this method public void tableChanged(TableModelEvent e){

Kindly suggest me in this regard. I have another option when "Refresh" button is clicked it will call the frame itself by disposing the last on. Is it good practice to do ? Suggest.

Answer 1

As discussed here , removal requires updating your model's internal data structure. One expedient approach is to simply create the array for some number of rows and columns:

data = new Double[rows][cols];
fireTableDataChanged();

Also consider Arrays.fill() to supplant the default value, null .

Answer 2

public static void removeAllDataFromJTable(JTable table) {
    f=flase;
    int numberOfRows = table.getRowCount();
    int numberOfColumns = table.getColumnCount();
    int rowCounter = 0;
    int columnCounter = 0;
    //we will travel to every row and clean it
    for (rowCounter = 0; rowCounter < numberOfRows; rowCounter++) {
        for (columnCounter = 0; columnCounter < numberOfColumns; columnCounter++) {
            table.setValueAt(null, rowCounter, columnCounter);
        }
    }
}

static boolean f = true;

 public void tableChanged(TableModelEvent e) {

 if(f){------}
 }

  public void methode(){
removeAllDataFromJTable(table);
f=true;
  }