setbackground

I have the folowing custom JPanel and I have aded it to my frame using Netbeans GUI builder but the background won't change! I can see the circle, drawing with g.fillOval(). What's wrong? public class Board extends JPanel{ private Player player; public Board(){ setOpaque(false); setBackground(Color.BLACK); } public void paintComponent(Graphics g){ super.paintComponent(g); g.setColor(Color.red); g.fillOval(player.getxCenter(), player.getyCenter(), player.getRadius(), player.getRadius()); } public void updatePlayer(Player player){ this.player=player; } } If your panel is 'not opaque'

I'm building an app that has plenty of screens. most of the screens have a View at the top with a background color. I often change that color using view.setBackgroundColor(color) Here comes the weird thing: sometimes after setting the color of one view, say to #f14fb7 , when navigating in the app, other views' backgrounds are set to that color without me wanting them to. It sometimes even happens to views I had not set an id for, so there is no way setBackgroundColor was called on those views. This happens rarely and is not consistant to any flow I tried. When I kill the app and restart it,

I am trying to set cornerRadius of UIButton but I dont know how to do it. If I do like this: button.layer.cornerRadius = 5; works well, if I do like this : button.layer.cornerRadius = 5; [button setBackgroundColor:[UIColor colorWithPatternImage:radialGradient]]; the corners are not rounded. I know I could solve this whit [button.layer setMasksToBounds:YES]; but I specifically looking for different solution, because I add some arrows to the button and if I set mask to bounds the arrow are masked. EDIT : radialGradient is made whit func + (UIImage *)getRadialGradientImage:(CGSize)size centre:

I am programming an editable combobox in a JFrame Form, but i want to change te background color. How the program works: If i click the button "press", then the combobox his background needs to become black. I tried: 1. cbo.setBackground(Color.BLACK); But it did nothing 2 cbo.getEditor().getEditorComponent().setBackground(Color.BLACK); ((JTextField) cbo.getEditor().getEditorComponent()).setOpaque(true); Does this: Code example: public class NewJFrame extends javax.swing.JFrame { private JComboBox cboCategorie; public NewJFrame() { initComponents(); cboCategorie = new JComboBox(); cboCategorie