如何设置仅在选择了jtable行后才能单击jbutton的条件

Question

Hello guys I need your help, i am absolute beginner. This is my problem, i have JTable in which i have some data from database with columns like: Id, Movie, Category, and Director. With part 1 of code i am selecting that data in JTable and sending it to part 2 of code in order to show in other JFrame for purpose of editing data or deleting from Database. I am using H2 database for my project. Now, my question is next, is there an option to create condition for that JButton to be clickable only if row is selected in JTable, or when is not selected row on JTable, and you press that JButton, to receive error message, and not to go to second JFrame. The code is working right now, but if don't click anything on JTable fields in second JFrame are empty.

I hope that i was clear enough.

part one

       table.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent arg0) {
            DefaultTableModel model=(DefaultTableModel)table.getModel();
            int selectedRowIndex=table.getSelectedRow();
            Id=(model.getValueAt(selectedRowIndex, 0).toString());
            Movie=(model.getValueAt(selectedRowIndex, 1).toString());
            Category=(model.getValueAt(selectedRowIndex, 2).toString());
            Director=(model.getValueAt(selectedRowIndex, 3).toString());

           }
           });

part two

    JButton btnDelete = new JButton("Delete");
    btnDelete.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            EditDelete rmv=new EditDelete();
            rmv.txtId.setText(Id);
            rmv.txtMovie.setText(Movie);
            rmv.txtCategory.setText(Category);
            rmv.txtDirector.setText(Director);
            rmv.setVisible(true);
            frmMovieDatabase.dispose();

            }
    });

Thanks in advance !

Answer 1

The JTable API has a method to get the number of selected rows: getSelectedRowCount that you can use on the JButton ActionListener to check if you can perform the deletion.

JButton btnDelete = new JButton("Delete");
    btnDelete.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            if (table.getSelectedRowCount() != 0){
               // perform the deletion
            }else{
               // Throw an exception etc...
            }
        }
    });

If you have any questions about handling or retrieving the selected values the page I linked above may have useful resources.