Code:
public class launcher implements ActionListener {
private static JFrame window;
private static JPanel panel;
private JButton createPassword;
private JButton seePassword;
public launcher() {
window = new JFrame();
panel = new JPanel();
window.setTitle("Password Vault");
window.setSize(400, 260);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setLocationRelativeTo(null);
window.setResizable(false);
window.setVisible(true);
window.getContentPane().add(panel); // Adds panel to JFrame
createPassword = new JButton("Create Password");
createPassword.setBounds(20, 100, 150, 100);
createPassword.addActionListener(this);
seePassword = new JButton("View Password");
seePassword.setLocation(20, 50);
seePassword.addActionListener(this);
panel.add(createPassword);
panel.add(seePassword);
}
public static void main(String[] args) {
new launcher();
}
Why can I not change the location of my JButtons? I have tried the setBounds and setLocation function but my buttons still stay on the top middle part of the JFrame window. I have also tried declaring my buttons inside the launcher() method and declaring them as a static variable.
You should NOT attempt to set the size/location of your buttons.
Swing was designed to be used with layout managers. The layout manager will set the size/location of the button based on the rules of the layout manager.
The default layout manager for a JPanel is the FlowLayout, which is why you see the button centered.
If you want to position the buttons differently, then you need to change the layout manager.
Read the section from the Swing tutorial on Layout Managers for more information and examples.
It looks like you want the buttons displayed vertically, so maybe a BoxLayout or GridLayout can be used depending on your exact requirement.
Other issues with your code:
Class names should start with an upper case character
There is no need to use static variables. That is not how the static keyword should be used
Components should be added to the frame BEFORE the frame is made visible.
You should be invoking pack() on the frame, BEFORE invoking setVisible(...) so the components can be displayed at their preferred size.
While you really shouldn't change the place of your components without a layout manager, there is a way. If you put this line of code into your code, it should work with setBounds:
window.setLayout(null);
Related
The question is that I cannot add JPanel and JLabel in the Frame at the same time.
When i using following code, only MyPanel will be visible. myFrame.add(myLabel);myFrame.add(myPanel);myFrame.setVisible(true);
when I execute: myFrame.add(myLabel);myFrame.setVisible(true);myFrame.add(myPanel);
only myLabel will be visible.
import javax.swing.*;
import java.awt.*;
public class Main {
public static void main(String[] args) {
MyFrame myFrame = new MyFrame();
MyLabel myLabel = new MyLabel();
MyPanel myPanel = new MyPanel();
myFrame.add(myLabel);
myFrame.add(myPanel);
myFrame.setVisible(true);
}
}
public class MyFrame extends JFrame {
MyFrame() {
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //exit out of application.
//https://docs.oracle.com/javase/7/docs/api/javax/swing/JFrame.html#setDefaultCloseOperation%28int%29
this.setSize(750, 750); //set the size.
this.setResizable(true);//resize the frame.
this.setTitle("Welocme to new world."); //set the Title.
ImageIcon imageIcon = new ImageIcon("logo.png");
this.setIconImage(imageIcon.getImage());
this.getContentPane().setBackground(new Color(217, 217, 217));
this.setBackground(Color.YELLOW);//this.setVisible(true);//Make the frame visible.
}}
import javax.swing.*;
import java.awt.*;
public class MyPanel extends JPanel {
MyPanel() {
this.setBackground(Color.white);
this.setBounds(2,2,25,25);
}}
import javax.swing.*;
import java.awt.*;
public class MyLabel extends JLabel {
MyLabel(){
this.setText("<html>Heaven <br/>Heaven's body\"<br/> Whirl around me <br/>Make me wonder</html>");
//,SwingConstants.CENTER);
//https://stackoverflow.com/questions/1090098/newline-in-jlabel
//How to print multi line in java
ImageIcon image = new ImageIcon("Cosmogony_Björk_Cover.jpg");
this.setIcon(image);
//jLabel.setForeground(new Color(217,217,217));
this.setForeground(Color.BLACK);
this.setFont(new Font("helvetica",Font.PLAIN,18));
this.setBackground(Color.gray);
this.setOpaque(true);
//jLabel.setVerticalTextPosition(JLabel.TOP); Set the relative text position of the label.
//jLabel.setBorder();
this.setVerticalAlignment(JLabel.CENTER);
this.setHorizontalAlignment(JLabel.CENTER);
}}
The default Layout Manager of JFrame is the BorderLayout.
Since you did not change the layout manager of your JFrame this is also the current layout manager used in your snippet.
Usually, when using the BorderLayout, you specify which area of the BorderLayout should be populated when adding a component. This is usually done via
frame.add(component, BorderLayout.CENTER);
Notice the area specification in the add() method, which tells the BorderLayout where to place the component.
Here is the issue however. If you use the add() method in combination with the BorderLayout without specifying the placement of the component, it will always place the component in BorderLayout.CENTER. (Causing the component which is currently there to be replaced)
To work around this, do one of the following things:
Specify the placement explicitly, so both components will show up:
frame.add(component1, BorderLayout.PAGE_START);
frame.add(component2, BorderLayout.CENTER);
Or use a different Layout Manager, which will take care of the placement for you. E.g. FlowLayout
JPanel contentPanel = new JPanel(); // JPanel uses flowlayout by default!
contentPanel.add(component1);
contentPanel.add(component2);
myFrame.setContentPane(contentPanel);
You could also explicitly set the layout:
Container contentPane = myFrame.getContentPane();
// creates new FlowLayout and sets on content pane
contentPane.setLayout(new FlowLayout());
contentPane.add(component1);
contentPane.add(component2);
Sidenotes:
Look through the Laying out components within a container Oracle tutorial, which will give you more information on which layout managers there are and how to work with them.
When building your GUI, setVisible() on the JFrame should be the last thing you are doing after adding all components. Because if you add components after setting the frame visible, the changes will not immediately take effect without you telling swing that something changed.
When correctly working with the Swing Layout Managers, there should be no need to use things like setBounds(...) or setSize(). After adding all components, calling pack() on the JFrame is the preferred way to go. This will size the JFrame according to the preferred size of the components inside.
I am creating a user system to hold multiple details of multiple users. so i would like to create a button that would be able to create another button. when the second button is pressed a form will open for the user to fill. I have already created the form for the user to fill but i cannot manage to make the button to create more buttons to work. I have coded this but it does not show the button on the Jpanel.
I have created the following code:
private void mainButtonActionPerformed(java.awt.event.ActionEvent evt) {
JButton b=new JButton("Click Here");
b.setBounds(50,100,95,30);
jPanel3.add(b);
b.setVisible(true);
}
This doesn't seem to create a new button within jPanel3. Have I typed up the code incorrectly or is there an alternative correct way of doing this?
I would like 3 buttons in a row and then a new row of buttons.
Your code and question is missing too much information to be answered completely or well. About all I can say is
Always call jPanel3.revalidate() and jPanel3.repaint() on the container after adding or removing components from it as this tells the container's (here jPanel3) layout managers to re-layout all components and then re-draw them.
The container's layout manager is key for this to work well -- we have no idea what it is at the moment, and some layout managers will allow you to do this easily (e.g., FlowLayout, GridLayout) while others won't (e.g., GroupLayout).
There's no need for b.setVisible(true); since your newly created JComponent (JButton here) is already visible by default.
You appear to assume that it's using null layouts since you're calling setBounds(...), and this is a Bad Idea™. While null layouts and setBounds() might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one.
When asking such questions, try to create and post with the question a small but complete program that we can test and run, and that illustrates your problem, a minimal example program (please click on the link).
For example, my MCVE that shows how your code can work:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import javax.swing.*;
#SuppressWarnings("serial")
public class AddButton extends JPanel {
private JPanel jPanel3 = new JPanel(); // panel to hold buttons
public AddButton() {
// create JButton that will add new buttons to jPanel3
JButton addMoreButtonsBtn = new JButton("Add More Buttons");
// give it an ActionListener
addMoreButtonsBtn.addActionListener(e -> {
final JButton newButton = new JButton("Click Here");
// when you click it, it removes itself (just for grins)
newButton.addActionListener(e2 -> {
jPanel3.remove(newButton);
// again revalidate and repaint
jPanel3.revalidate();
jPanel3.repaint();
});
// add to jPanel3, the "container"
jPanel3.add(newButton);
// revalidate and repaint the container
jPanel3.revalidate();
jPanel3.repaint();
});
// create a JPanel and put the add more buttons button to it
JPanel bottomPanel = new JPanel();
bottomPanel.add(addMoreButtonsBtn);
// give jPanel3 a layout that can handle new buttons
// a gridlayout with 1 column and any number of rows
jPanel3.setLayout(new GridLayout(0, 1));
// add it to the top of another JPanel that uses BorderLayout
JPanel borderLayoutPanel = new JPanel(new BorderLayout());
borderLayoutPanel.add(jPanel3, BorderLayout.PAGE_START);
// and add that to a JScrollPane, so we can add many buttons and scroll
JScrollPane scrollPane = new JScrollPane(borderLayoutPanel);
// make the vert scrollbar always visible
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
// force GUI to be larger
setPreferredSize(new Dimension(400, 200));
// give the main JPanel a BorderLayout
setLayout(new BorderLayout());
// and add scrollpane to center
add(scrollPane, BorderLayout.CENTER);
// add bottom panel to the bottom
add(bottomPanel, BorderLayout.PAGE_END);
}
private static void createAndShowGui() {
AddButton mainPanel = new AddButton();
JFrame frame = new JFrame("AddButton");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
I've put quite a few objects into this JFrame. however many of them do not appear until I hover them mainly the button as well as the JTextField. I only included the JSpinner components so that it wasn't so long. Is there anything in my spinners or lacking with my spinners that would make them not appear?
I've stripped it down alot so that it is just one textfield. Still nothing shows up. I've put everything in panels, however still nothing shows up.
public static void screen() {
JFrame myFrame = new JFrame("Yore");
myFrame.setAlwaysOnTop(true);
myFrame.setResizable(false);
myFrame.setForeground(Color.BLACK);
myFrame.setSize(300,365);
myFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
myFrame.setVisible(true);
myFrame.setBackground(Color.WHITE);
JPanel panel = new JPanel();
myFrame.setContentPane(panel);
JTextField Username = new JTextField();
Username.setText("Username");
Username.setColumns(10);
panel.add(Username);
}
Sorry, i forgot pne statement.
public static void screen() {
JFrame myFrame = new JFrame("Yore");
myFrame.setAlwaysOnTop(true);
myFrame.setResizable(false);
myFrame.setForeground(Color.BLACK);
myFrame.setSize(300,365);
myFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
myFrame.setVisible(true);
myFrame.setBackground(Color.WHITE);
JPanel panel = new JPanel();
myFrame.setContentPane(panel);
JTextField Username = new JTextField();
Username.setText("Username");
Username.setColumns(10);
panel.add(Username);
panel.validate();
}
Try using a layout manager for the frame. Also, add a JPanel to the frame and add all of the Spinners to the Panel.
Using the correct layout manager, you can programatically add the Spinners to the Panel, so that you do not need to hard code the bounds. You will also have the ability to have them resize as the window resizes, for example.
Take a look here to get started with layout managers.
https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
myFrame.getContentPane() returns an AWT container, not a Swing component. To change this you have to use
JPanel panel = new JPanel();
panel.add(..);
myFrame.setContentPane(panel);
panel.validate();
Add your spinners to the panel and your problem is solved.
Add spinners to the panel. and then add panel to your JFrame.
panel.add(spinner_5);
I have to align a button on my program to the exact middle, the current code I have runs it but displays the button as large as the program, I am wanting a center button that is a specific size, here is what I tried
/**
* Created by Timk9 on 11/04/2016.
*/
import javax.swing.*;
import java.awt.*;
public class Test extends JFrame {
{
JFrame window = new JFrame("Test");
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setResizable(true);
window.setSize(600, 600);
window.setVisible(true);
window.setLocationRelativeTo(null);
JPanel p = new JPanel(new GridBagLayout());
//Button does not appear until I resize the program?
JButton b1 = new JButton("Click here");
GridBagConstraints c = new GridBagConstraints();
p.add(b1);
window.add(p);
}
public static void main(String[] args) {
new Test();
}
}
JPanel p = new JPanel(new GridBagLayout());
You create a panel with a GridBagLayout which is a good layout manager to use to center the component.
p.add(b1);
But then you add the button to the panel without using any contraints.
The code should be:
p.add(b1, c);
//Button does not appear until I resize the program?
All components should be added to the frame BEFORE the frame is made visible. The setVisible(...) statement should be the last statement of the constructor.
Also could you point out which part is an instance initializer block, I thought I was using a constructor
See the FrameDemo example from the Swing tutorial on How to Make Frames for a better way to structure your code so you follow Swing conventions. Start with the working code and make the changes to add your panel containing the button, instead of using the JLabel. Note you no longer need to use the getContentPane() method, you can just add the panel directly to the frame.
It is the LayoutManager that defines how components are layed out where and how big. GridLayout which you are using e. g. divides the available space in equal grid fields and makes the components completely fill this space which is why your button is as big as your application. See here for more info about LayoutManagers: https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
Btw. your code is not compilable: new JButton("he"),JButton.ALIGN_CENTER)
I have a single JLabel in my JFrame, initially displayed using pack().
My problem is that whenever I try to resize the window, the JLabel also moves (depending on which side of the window is resized), largely due to the layout of the JFrame.
To be more specific, whenever I resize the window up/down, the JLabel stays centered. I would like that not be the case.
I'm sorry if my question is confusing. I'll gladly provide diagrams if requested.
public class JavaApplication8 {
public static void main(String[] args) throws MalformedURLException {
// TODO code application logic here
JFrame window = new JFrame("test");
URL bgURL = new URL("https://si0.twimg.com/profile_images/3585146044/3b695fa73490227f792fa4e46d4a7a57.jpeg");
ImageIcon bg = new ImageIcon(bgURL);
JLabel label = new JLabel(bg);
window.add(label, BorderLayout.CENTER);
window.pack();
window.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
window.setLocationRelativeTo(null);
window.setVisible(true);
}
}
Use a different layout manager:
window.setLayout(new FlowLayout());
would be sufficient for the example.
Another possibility, if you want to keep using BorderLayout, is placing the label to a different position:
window.add(label, BorderLayout.NORTH);
Also note that you should access swing components only from the event dispatch thread.