图形用户界面

Question

So, I am trying to create buttons 8 on left and right side each. And I am really new to GUI. So, I am not sure how to change the colour and shape, to make those buttons a circle and color them in red and blue...This what I have so far...

import javax.swing.*;

import java.awt.*;

public class Arrangement {

// main must be static
public static void main(String[] args) {
    Arrangement arrangement = new Arrangement();
    arrangement.handle();
}

public void handle() {
    JFrame f= new JFrame();
    f.setVisible(true);
    f.setSize(600,400);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel p = new JPanel (new GridBagLayout());//in the constructor u specify the layout :)
    JPanel a = new JPanel (new GridBagLayout());


    JButton b1 = new JButton("Button 1");
    JButton b2 = new JButton("Button 2");
    JButton b3= new JButton ("Button 3");
    JButton b4= new JButton ("Button 4");
    JButton b5= new JButton ("Button 5");
    JButton b6= new JButton ("Button 6");
    JButton b7 = new JButton("Button 7");
    JButton b8 = new JButton("Button 8");
    JButton b9 = new JButton ("Button 9");
    JButton b10 = new JButton ("Button 10");
    JButton b11 = new JButton ("Button 11");
    JButton b12 =new JButton ("Button 12");
    JButton b13 = new JButton("Button 13");
    JButton b14= new JButton("Button 14");
    JButton b15= new JButton ("Button 15");
    JButton b16 = new JButton ("Button 16");

    GridBagConstraints c= new GridBagConstraints();
    GridBagConstraints d= new GridBagConstraints();

    c.insets = new Insets(5,5,5,5);//spacing

    c.gridx=0;
    c.gridy=1;
    p.add(b1,c);

    c.gridx=0;
    c.gridy=2;      
    p.add(b2,c);

    c.gridx=0;
    c.gridy=4;      
    p.add(b3,c);

    c.gridx=0;
    c.gridy=6;      
    p.add(b4,c);

    c.gridx=0;
    c.gridy=8;      
    p.add(b5,c);

    c.gridx=0;
    c.gridy=10;     
    p.add(b6,c);

    c.gridx=0;
    c.gridy=11;     
    p.add(b7,c);

    c.gridx=0;
    c.gridy=12;     
    p.add(b8,c);

    d.insets = new Insets(5,5,5,5);

    d.gridx=0;
    d.gridy=1;
    a.add(b9,d);

    d.gridx=0;
    d.gridy=2;
    a.add(b10,d);

    d.gridx=0;
    d.gridy=3;
    a.add(b11,d);

    d.gridx=0;
    d.gridy=4;
    a.add(b12,d);

    d.gridx=0;
    d.gridy=6;
    a.add(b13,d);

    d.gridx=0;
    d.gridy=8;
    a.add(b14,d);

    d.gridx=0;
    d.gridy=10;
    a.add(b15,d);

    d.gridx=0;
    d.gridy=12;
    a.add(b16,d);


    f.add(p, BorderLayout.WEST);
    f.add(a, BorderLayout.EAST);

}

} Now the problem here is I cant use "this. ", with static and if I remove static I get an error saying I need to include static for my code to work... Can someone help me debug this :'( and direct me as to how can I get my buttons to be desired shape and colour...! Any help would be greatly appreciated <3

Answer 1

This was too long for a comment, but it relates to your use of the static keyword:

The reason you can't use the this keyword and must have static is because your code is executed in the static main method. Instead, move all the code from main to a new method in the Arrangement class, say it's called handle() . Then create an instance of Arrangement at the beginning of your main class and call handle() . For instance:

public class Arrangement {

    // main must be static
    public static void main(String[] args) {
        Arrangement arrangement = new Arrangement();
        arrangement.handle();
    }

    public void handle() {
        /* Put the rest of your code here and 
         * you'll be able to use the 'this' keyword */
    }

}

Additional questions that might be helpful:

• Why can't we use this keyword in a static method
• What does the static keyword do in a class?
• Difference between Static methods and Instance methods

EDIT A similar task was described in this question . The user wanted to have clickable circles and squares display on-screen. Rather than using a JButton he simply drew shapes on-screen.

Answer 2

use can use custom icons for your button as

jButton1.setIcon(new javax.swing.ImageIcon("C:\\\\Users\\\\admin\\\\Desktop\\\\image.jpg"));

if you want to set color to button then use following code

    jButton1.setBackground(Color.BLUE);
    jButton1.setForeground(Color.GREEN);

hope my code helps you in this regard.

Answer 3

Well, there are three issues with your code.The first one is already discussed. You can't reference non static variables from a static context.

this word is not static and main method is static

Now, to change background color, effectively you call the setBackground() method on the element you want the color to change.

Finally, to make the shape of the button you can follow this link: Making buttons round

Bassically what you are doing here is extending the jbutton class. Not allowing it to draw its own shape and use graphics to draw on it. You can use graphics to draw on every java GUI componnent. All you have to do is to implement de paint componnent method

By the way, here is a clearer and simpler way to display image icons.

---

One last comment, the key to make it easier to debug is trying to write clean and organized code. For example, I can see that you repeat the following code once and again:

c.gridx=0;
c.gridy=1;
p.add(b1,c);

What you can do is create a function to pack it

void pack(Insets target, int xCoord,int yCoord,Component comp ){
target.gridx=xCoord;
target.gridy=yCoord;
p.add(comp, target);
}

you can create an array with all the buttons too, so you can use a for loop to pack them:

JButton[] buttons= new JButton[8];

for(int j=0;j<16;j++){
    buttons[j]= new JButton("Button "+(j+1));
}

Packing of left buttons:

for(int j=0;j<8;j++){
    pack(c, 0, j+1,buttons[j+1]);
}

---

Thi is the final result

import javax.swing.*;
import java.awt.*;
import java.awt.*;
import java.awt.image.*;
public class Arrangement {



public void main(String[] args) {
    JFrame f= new JFrame();
    f.setVisible(true);
    f.setSize(600,400);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel p = new JPanel (new GridBagLayout());//in the constructor u specify the layout :)
    JPanel a = new JPanel (new GridBagLayout());
    Arrangement arr= new Arrangement();
    for(int j=0;j<16;j++){
       if(j==0)
        Image img= new ImageIcon(arr.getClass().getResource("/Red.png")).getImage();
//Supposing you followed the link and created the class
       buttons[j]= new RoundButton("Button "+(j+1));
    }

    GridBagConstraints c= new GridBagConstraints();
    GridBagConstraints d= new GridBagConstraints();

    c.insets = new Insets(5,5,5,5);//spacing

    for(int j=0;j<8;j++){
       arr.pack(c, 0, j+1,buttons[j],p);
    }
    d.insets = new Insets(5,5,5,5);

    for(int j=0;j<8;j++){
       arr.pack(d, 0, j+9,buttons[j+8],a);
    }


    f.add(p, BorderLayout.WEST);
    f.add(a, BorderLayout.EAST);

}
void pack(Insets target, int xCoord,int yCoord,Component comp, Panel container ){
target.gridx=xCoord;
target.gridy=yCoord;
container.add(comp, target);
}

}