How to place a JButton at a desired location in a JFrame using Java

问题

I want to put a Jbutton on a particular coordinate in a JFrame. I put setBounds for the JPanel (which I placed on the JFrame) and also setBounds for the JButton. However, they dont seem to function as expected.

My Output:

This is my code:

import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Control extends JFrame {

    // JPanel
    JPanel pnlButton = new JPanel();
    // Buttons
    JButton btnAddFlight = new JButton("Add Flight");

    public Control() {
        // FlightInfo setbounds
        btnAddFlight.setBounds(60, 400, 220, 30);

        // JPanel bounds
        pnlButton.setBounds(800, 800, 200, 100);

        // Adding to JFrame
        pnlButton.add(btnAddFlight);
        add(pnlButton);

        // JFrame properties
        setSize(400, 400);
        setBackground(Color.BLACK);
        setTitle("Air Traffic Control");
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static void main(String[] args) {
        new Control();
    }
}

How can place the JButton at coordinate (0, 0)?

回答1:

Following line should be called before you add your component

pnlButton.setLayout(null);

Above will set your content panel to use absolute layout. This means you'd always have to set your component's bounds explicitly by using setBounds method.

In general I wouldn't recommend using absolute layout.

回答2:

Use child.setLocation(0, 0) on the button, and parent.setLayout(null). Instead of using setBounds(...) on the JFrame to size it, consider using just setSize(...) and letting the OS position the frame.

//JPanel
JPanel pnlButton = new JPanel();
//Buttons
JButton btnAddFlight = new JButton("Add Flight");

public Control() {

    //JFrame layout
    this.setLayout(null);

    //JPanel layout
    pnlButton.setLayout(null);

    //Adding to JFrame
    pnlButton.add(btnAddFlight);
    add(pnlButton);

    // postioning
    pnlButton.setLocation(0,0);

回答3:

Define somewhere the consts :

private static final int BUTTON_LOCATION_X = 300;  // location x 
private static final int BUTTON_LOCATION_Y = 50;   // location y 
private static final int BUTTON_SIZE_X = 140;      // size height
private static final int BUTTON_SIZE_Y = 50;       // size width

and then below :

                JButton startButton = new JButton("Click Me To Start!");
                // startButton.setBounds(300, 50,140, 50 );
                startButton.setBounds(BUTTON_LOCATION_X
                                    , BUTTON_LOCATION_Y,
                                      BUTTON_SIZE_X, 
                                      BUTTON_SIZE_Y );
                contentPane.add(startButton);

where contentPane is the Container object that holds the entire frame :

 JFrame frame = new JFrame("Some name goes here");
 Container contentPane = frame.getContentPane();

I hope this helps , works great for me ...

回答4:

You should set layout first by syntax pnlButton.setLayout(), and then choose the most suitable layout which u want. Ex: pnlButton.setLayout(new FlowLayout(FlowLayout.LEADING, 5, 5));. And then, take that JButton into JPanel.

回答5:

I have figured it out lol. for the button do .setBounds(0, 0, 220, 30) The .setBounds layout is like this (int x, int y, int width, int height)

回答6:

First, remember your JPanel size height and size width, then observe: JButton coordinates is (xo, yo, x length , y length). If your window is 800x600, you just need to write:

JButton.setBounds(0, 500, 100, 100);

You just need to use a coordinate gap to represent the button, and know where the window ends and where the window begins.

来源：https://stackoverflow.com/questions/3195666/how-to-place-a-jbutton-at-a-desired-location-in-a-jframe-using-java

标签

java

swing

jframe

jbutton