java.lang.Object无法转换为int

Question

I have a problem with downloading the number from JTable. In Eclipse I have jre JavaSE 1.7 and it is all ok. I opened my project in IntelliJ IDEA and chose SDK java jdk 1.8.

private int;
public void tableEdit(final JTable table) {

        table.getModel().addTableModelListener(new TableModelListener() {
            @Override
            public void tableChanged(TableModelEvent e) {
                // TODO Auto-generated method stub
                if (table.getCellEditor() != null) {

                    int col = table.getSelectedColumn();
                    id =  (int)table.getValueAt(table.getSelectedRow(), 0); //ERROR

Error:

java: incompatible types: java.lang.Object cannot be converted to int

Edit:

New problem: The JTable I have 2 fields, ID and field2 (combobox) after selecting the value from the combobox wants to retrieve a value from the ID field so that they know which row I need to update.

categoryBox.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent event) {
                if (newrow_flag == 0) {
                    JComboBox comboBox = (JComboBox) event.getSource();
                    Object item = event.getItem();
                    if (event.getStateChange() == ItemEvent.SELECTED
                            && box_flag_category > 0) {

                        Category selected_category = (Category) categoryBox
                                .getSelectedItem();

                        int rowid = Integer.getInteger(itemTable.getValueAt(
                                itemTable.getSelectedRow(), 0).toString()); //Error

                        id_category = selected_category.getId();


                        fireItemEvent(new ItemsEvent(rowid, "produkty", null,
                                null, null, id_category, id_company, "update"),
                                "box_category");

                    }
                    box_flag_category++;
                }
            }
        });

And error:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.magazyn.view.View$9.itemStateChanged(View.java:659)
    at javax.swing.JComboBox.fireItemStateChanged(JComboBox.java:1223)
    at javax.swing.JComboBox.selectedItemChanged(JComboBox.java:1280)
    at javax.swing.JComboBox.contentsChanged(JComboBox.java:1327)
    at javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:118)
    at javax.swing.DefaultComboBoxModel.setSelectedItem(DefaultComboBoxModel.java:93)
    at javax.swing.JComboBox.setSelectedItem(JComboBox.java:576)
    at javax.swing.JComboBox.setSelectedIndex(JComboBox.java:622)
    at javax.swing.plaf.basic.BasicComboPopup$Handler.mouseReleased(BasicComboPopup.java:834)
    at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:290)
    at java.awt.Component.processMouseEvent(Component.java:6527)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    [...]

Error points to this line:

int rowid = Integer.getInteger(itemTable.getValueAt(
                                itemTable.getSelectedRow(), 0).toString());

Answer 1

Well look at the error:

java: incompatible types: java.lang.Object cannot be converted to int

And then look at the line that throws the error:

id =  (int)table.getValueAt(table.getSelectedRow(), 0);

Now as you can see, you're attempting to cast an Object to an int . This is not allowed. So you need to be a little more creative:

int id = Integer.parseInt(table.getValueAt(table.getSelectedRow(), 0).toString()); 

Answer 2

I have a problem with downloading the number from JTable.

• put integer value directly to JTable/XxxTableModel , to avoid any parsing at runtime

• JTable is designated to store various data types in its XxxTableModel

• (for DefaultTableModel isn't required) then to override getColumnClass

---

edit

re:

@christopher, when I chose value from ComboBox i get error Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String at com.magazyn.view.View$9.itemStateChanged(View.java:659) at javax.swing.JComboBox.fireItemStateChanged(JComboBox.java:1223) at javax.swing.JComboBox.selectedItemChanged(JComboBox.java:1280)

• don't put JComboBox to JTable, read Oracle tutorial How to use Tables - Using a Combo Box as an Editor for working code example (String instance), model should be store only initial or last selected value from JComboBox as Editor

• put numbers to JComboBox/DefaultComboBoxModel directly, then returns is number

• TableModelListener firing an event after CellEditor() == null, then code doesn't make me sence

Answer 3

See class Jtable

public Object getValueAt(int row, int column) {
        return getModel().getValueAt(convertRowIndexToModel(row),
                                     convertColumnIndexToModel(column));
    }

Method has return type as Object .

use Integer.parseInt();