如何在一帧中添加绘图（绘制方法）和另一个带控件的面板？

Question

I need to have a JFrame where the upper part is a drawing made by paint() and the lower part is a panel composed of JLabel , JTextField and JButton components.

Is this possible? How am I supposed to do this?

Answer 1

I need to have a Jframe where the upper part is a drawing made by paint() and the lower part is a panel composed of JLabel, JTextField and JButtons.

There is no conflict on what you want to do. You can have a main JPanel with 2 sub panels. One on the top for your drawings, the other at the bottom for containing your JComponents such as JButtons:

The structure in code may look like this:

class MainPanel extends JPanel{
    private DrawingSpace drawingSpace;  //Customized JPanel for drawing
    private JPanel subPanel;

    public MainPanel(){
        setPreferredSize(new Dimension(400, 400));
        initComponents();
    }

    private void initComponents(){
        drawingSpace = new DrawingSpace();
        subPanel = new JPanel();
    }
}

You can have a customized JPanel as follows (this is optional):

class DrawingSpace extends JPanel
{
    public DrawingSpace(){
        //Set size..etc
    }

    @Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        //perform your drawings here..
    }
}

After the implementations for the JPanels , you can just add an instance of MainPanel to the JFrame :

JFrame frame = new JFrame();
frame.add(new MainPanel());
//Other codes for JFrame not shown here

Answer 2

The soulution suggested by user3437460 (use a JPanel for the upper part, and override the painting methods in that JPanel) is the preferrable way to solve this.

However as you asked for a solution to directly paint the upper part (which is not advised, but there are solutions):

• A (nasty) workaround for the question would be overriding the necessary paint method of JFrame, draw your upper part, translate the graphics context by some 100 pixels and call inherited paint methods to draw the bottom part. (Note that you'll have layout manager issues, as the layout manager won't see the 100px height of the upper part. However, if you're using an absolute layout, it could work. Hacks, hacks hacks :(

• Another super-hack is to actually make the lower part big enough (if you use absolute layout, position your lower part at y=100px). Then add your own GlassPane and render the content for the upper part (or anywhere) on the glassPane.

• Of course you can create a dedicated layout manager, which leaves the top 100 px part empty. Use that layout manager, and then you get some empty space on the top, which you can draw on.

I think now you can agree that the problem is rather "how to put a custom drawn component on the top of the window" , which is solved by putting a custom drawn JPanel on the top of the window. Keep it easy! Peace!

ps: override paintComponent() instead of paint() of JPanel. See bottom of http://www.oracle.com/technetwork/java/painting-140037.html

Answer 3

For the painting portion, create a JPanel (or other paintable component) and override the paint method. Use a second JPanel and place all of your other components in that.

From there, check out how to do layout management at https://docs.oracle.com/javase/tutorial/uiswing/layout/using.html#set

The simplest way to do this is to use GridLayout, with the painted panel on the top half and the components panel on the bottom half.