问题
I´m rather new to Java and programming itself, so excuse me for the question. What I´m trying to do is the following:
I´m making a bookkeeping program. On the column where the income/outcome is displayed, I want it so when the user enters a negative number (eg. -1.150€), the number turns red( or any color really, but red is what most bookkeeping programs use). only that specific cell on that column only. I have not started with a code yet so I cannot input one here. I also do not need it to be right-aligned since I have already done that.
PS. Sorry if this post/question already exists, I searched but I found nothing that could help me much.
回答1:
A small example with double values in a single column. This version uses JTable.setDefaultRenderer for Double.class
.
You can also set colors
- From an override of JTable.prepareRenderer
- From a renderer set individually for columns by calling TableColumn.setCellRenderer;
TableColumn
instances can be retrieved from the TableColumnModel
import java.awt.*;
import javax.swing.*;
import javax.swing.table.DefaultTableCellRenderer;
@SuppressWarnings("serial")
public class TableWithColors {
protected static JTable createTable() {
Object[][] rows = new Object[][] {{1.23d},{-20.5d},{5.87d},{2.23d},{-7.8d},{-8.99d},{9d},{16.25d},{4.23d},{-26.22d},{-14.14d}};
Object[] cols = new Object[]{"Balance"};
JTable t = new JTable(rows,cols) {
@Override
public Class<?> getColumnClass(int column) {
if(convertColumnIndexToModel(column)==0) return Double.class;
return super.getColumnClass(column);
}
};
t.setDefaultRenderer(Double.class, new DefaultTableCellRenderer(){
@Override
public Component getTableCellRendererComponent(JTable table,Object value,boolean isSelected,boolean hasFocus,int row,int column) {
Component c = super.getTableCellRendererComponent(table,value,isSelected,hasFocus,row,column);
c.setForeground(((Double) value)>0 ? Color.BLUE : Color.RED);
return c;
}
});
return t;
}
private static JFrame createFrame() {
JFrame f = new JFrame("Table with colors");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLayout(new BorderLayout());
f.add(new JScrollPane(createTable()),BorderLayout.CENTER);
f.setSize(new Dimension(60,255));
return f;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
createFrame().setVisible(true);
}
});
}
}
Goes like:
来源:https://stackoverflow.com/questions/35431232/jtable-cell-text-color-changing