Develop Reference

Java - how to zoom in/zoom out text in JTextArea

I am writing in a notepad. And I want to implement text scaling in my notepad. But I don't know how to do it. I'm trying to find it but everyone is suggesting to change the font size. But I need another solution.
I am create new project and add buttons and JTextArea.
package zoomtest;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JTextArea;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class zoom {
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
zoom window = new zoom();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public zoom() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
frame.getContentPane().add(panel, BorderLayout.NORTH);
JButton ZoomIn = new JButton("Zoom in");
ZoomIn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//Code here...
}
});
panel.add(ZoomIn);
JButton Zoomout = new JButton("Zoom out");
Zoomout.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//Code here...
}
});
panel.add(Zoomout);
JTextArea jta = new JTextArea();
frame.getContentPane().add(jta, BorderLayout.CENTER);
}
}

Introduction
Oracle has a helpful tutorial, Creating a GUI With Swing. Skip the Learning Swing with the NetBeans IDE section. Pay close attention to the Laying Out Components Within a Container section.
I reworked your GUI. Here's how it looks when the application starts. I typed some text so you can see the font change.
Here's how it looks after we zoom out.
Here's how it looks after we zoom in.
Stack Overflow scales the images, so it's not as obvious that the text is zooming.
Explanation
Swing was designed to be used with layout managers. I created two JPanels, one for the JButtons and one for the JTextArea. I put the JTextArea in a JScrollPane so you could type more than 10 lines.
I keep track of the font size in an int field. This is a simple application model. Your Swing application should always have an application model made up of one or more plain Java getter/setter classes.
Code
Here's the complete runnable code.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class ZoomTextExample {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
new ZoomTextExample();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
private int pointSize;
private Font textFont;
private JFrame frame;
private JTextArea jta;
private JTextField pointSizeField;
public ZoomTextExample() {
this.pointSize = 16;
this.textFont = new Font(Font.DIALOG, Font.PLAIN, pointSize);
initialize();
}
private void initialize() {
frame = new JFrame("Text Editor");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createButtonPanel(), BorderLayout.NORTH);
frame.add(createTextAreaPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtonPanel() {
JPanel panel = new JPanel(new FlowLayout());
panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));
JButton zoomIn = new JButton("Zoom in");
zoomIn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
incrementPointSize(+2);
updatePanels();
}
});
panel.add(zoomIn);
panel.add(Box.createHorizontalStrut(20));
JLabel label = new JLabel("Current font size:");
panel.add(label);
pointSizeField = new JTextField(3);
pointSizeField.setEditable(false);
pointSizeField.setText(Integer.toString(pointSize));
panel.add(pointSizeField);
panel.add(Box.createHorizontalStrut(20));
JButton zoomOut = new JButton("Zoom out");
zoomOut.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
incrementPointSize(-2);
updatePanels();
}
});
panel.add(zoomOut);
return panel;
}
private JPanel createTextAreaPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));
jta = new JTextArea(10, 40);
jta.setFont(textFont);
JScrollPane scrollPane = new JScrollPane(jta);
panel.add(scrollPane, BorderLayout.CENTER);
return panel;
}
private void updatePanels() {
pointSizeField.setText(Integer.toString(pointSize));
textFont = textFont.deriveFont((float) pointSize);
jta.setFont(textFont);
frame.pack();
}
private void incrementPointSize(int increment) {
pointSize += increment;
}
}

Trying to set the location of a Java Button using JFrame isn't working?

Please look below for Edits.
So I've looking over numerous "solutions" to fix my problem, but I just can't seem to get it working.
This is what my application looks like with the code below:
Basically, I want to set the location of a button, but I can't manage to do so. Here is my code:
package me.cervinakuy.application;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ControlPanel3 extends JFrame {
JPanel panel = new JPanel();
JButton startRobo = new JButton();
JButton stopRobo = new JButton();
JButton restartRobo = new JButton();
public ControlPanel3() {
// setLayout(null);
setSize(1000, 700);
setResizable(false);
setLocation(450, 150);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setBackground(new Color(45, 48, 55));
setTitle("Espin Software | Control Panel");
setVisible(true);
startRobo.setIcon(new ImageIcon(getClass().getResource("/resources/startRobo.png")));
stopRobo.setIcon(new ImageIcon(getClass().getResource("/resources/stopRobo.png")));
restartRobo.setIcon(new ImageIcon(getClass().getResource("/resources/restartRobo.png")));
startRobo.setBorder(null);
stopRobo.setBorder(null);
restartRobo.setBorder(null);
startRobo.setLocation(100, 100);
panel.add(startRobo);
panel.add(stopRobo);
panel.add(restartRobo);
panel.setOpaque(false);
add(panel);
validate();
}
}
EDIT:
I have now managed to create a GUI of what I was initially looking for, however, I have a new problem. Buttons are now pressable from different parts of the GUI, rather than only on the image. For those interested, here is what I have been able to accomplish:
New GUI look.
Updated Code:
package me.cervinakuy.application;
import java.awt.Color;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ControlPanel3 extends JFrame {
JPanel panel = new JPanel();
JButton startRobo = new JButton();
JButton stopRobo = new JButton();
JButton restartRobo = new JButton();
public ControlPanel3() {
// setLayout(null);
setSize(1000, 700);
setResizable(false);
setLocation(450, 150);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setBackground(new Color(45, 48, 55));
setTitle("Espin Software | Control Panel");
setVisible(true);
startRobo.setIcon(new ImageIcon(getClass().getResource("/resources/startRobo.png")));
stopRobo.setIcon(new ImageIcon(getClass().getResource("/resources/stopRobo.png")));
restartRobo.setIcon(new ImageIcon(getClass().getResource("/resources/restartRobo.png")));
startRobo.setBorder(null);
stopRobo.setBorder(null);
restartRobo.setBorder(null);
panel.setLayout(null);
startRobo.setLocation(200, 200);
startRobo.setBounds(5, -95, 300, 300);
stopRobo.setBounds(5, 0, 300, 300);
restartRobo.setBounds(5, 95, 300, 300);
panel.add(startRobo);
panel.add(stopRobo);
panel.add(restartRobo);
panel.setOpaque(false);
add(panel);
validate();
}
}

There are typically a number of ways to layout components that end with the same effect. In this example, we use a panel to contain the buttons in a column (buttonContainer using a GridLayout) then a panel to restrict that container to the top (buttonConstrainPanel using a BorderLayout) then a container to put that panel on the left (ui with BorderLayout).
It could also be achieved using a single GridBagLayout or a GroupLayout, though the logic of achieving it might not be as simple.
The focus border seen on the blue button indicates the limits of where a mouse click would activate the button.
import java.awt.*;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class ThreeButtonAlignedLeft {
private JComponent ui = null;
private String prefix = "http://i.stack.imgur.com/";
private String[] suffix = {"gJmeJ.png","T5uTa.png","wCF8S.png"};
ThreeButtonAlignedLeft() {
try {
initUI();
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
}
public void initUI() throws MalformedURLException {
if (ui!=null) return;
ui = new JPanel(new BorderLayout(4,4));
ui.setBorder(new EmptyBorder(4,4,4,4));
JPanel buttonContainer = new JPanel(new GridLayout(0, 1, 5, 5));
for (int ii=0; ii<suffix.length; ii++) {
JButton b = new JButton(new ImageIcon(new URL(prefix + suffix[ii])));
b.setBorderPainted(false);
b.setMargin(new Insets(0,0,0,0));
b.setContentAreaFilled(false);
buttonContainer.add(b);
}
JPanel buttonConstrainPanel = new JPanel(new BorderLayout(0, 0));
buttonConstrainPanel.add(buttonContainer, BorderLayout.PAGE_START);
ui.add(buttonConstrainPanel, BorderLayout.LINE_START);
}
public JComponent getUI() {
return ui;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception useDefault) {
}
ThreeButtonAlignedLeft o = new ThreeButtonAlignedLeft();
JFrame f = new JFrame(o.getClass().getSimpleName());
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setLocationByPlatform(true);
f.setContentPane(o.getUI());
f.pack();
f.setMinimumSize(f.getSize());
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}

Use a JButton to add new panels at runtime

I feel as beginner I may have bitten off too much in regards to application building. That said, I am working on developing an application for a friend that will have prompts where each JPanel will provide fields to create an object to be used later. What I would like to have happen is that when the panel loads, it displays one object creation panel and a button to dynamically add a new panel if the user wants to make multiples (the plus button would add the new panel).
I have drawn up something in paint to illustrate this:
By my very limited understanding, I can create a panel to hold these sub-panels, and then add a action listener to the '+' button to create new panels. The only way I could think to implement this is to create a constructor for the panel I want to add. Is this possible? Let me show you what I have:
package com.company;
import java.awt.*;
import javax.swing.*;
/**
* Created by Travis on 3/1/2015.
*/
public class MainSnakeGui extends JFrame{
protected int panelCount;
//row 1
JPanel row1 = new JPanel();
JLabel splitSnakeLabel = new JLabel("Create a Split Snake", JLabel.CENTER);
//row 2
JPanel row2 = new JPanel();
JButton addButton = new JButton("+");
public MainSnakeGui() {
super("Snake Channels");
setSize(550, 400);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GridLayout layout = new GridLayout(5, 1, 10, 10);
setLayout(layout);
FlowLayout layout1 = new FlowLayout(FlowLayout.CENTER, 10, 10);
row1.setLayout(layout1);
row1.add(splitSnakeLabel);
add(row1);
GridLayout layout2 = new GridLayout(1, 2, 10, 10);
row2.setLayout(layout2);
row2.add(addButton);
MainSnakeConstructor snakePanel = new MainSnakeConstructor();
row2.add(snakePanel);
add(row2);
setVisible(true);
}
public static void setLookAndFeel () {
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (Exception e) {
}
}
public static void main(String[] arg) {
MainSnakeGui.setLookAndFeel();
MainSnakeGui frame = new MainSnakeGui();
}
}
Here is the constructor:
package com.company;
import javax.swing.*;
import java.awt.*;
/**
* Created by Travis on 3/1/2015.
*/
public class MainSnakeConstructor extends JFrame {
public MainSnakeConstructor () {
JPanel splitSnakeRow = new JPanel();
JLabel snakeNameLabel = new JLabel("Snake Name");
JLabel channelCountLabel = new JLabel("Channel Count");
JCheckBox artistSuppliedCheckBox = new JCheckBox("Artist Supplied?");
JTextField snakeNameTextField = new JTextField(30);
JTextField channelCountTextField = new JTextField(3);
GridLayout layout = new GridLayout(3,2,10,10);
splitSnakeRow.setLayout(layout);
splitSnakeRow.add(snakeNameLabel);
splitSnakeRow.add(channelCountLabel);
splitSnakeRow.add(artistSuppliedCheckBox);
splitSnakeRow.add(snakeNameTextField);
splitSnakeRow.add(channelCountTextField);
add(splitSnakeRow);
}
}

Think about it differently. You want a button that allows you to add new panels, so you really only need a single button.
From there, you need some kind common panel which provides the functionality you want to the user (the creation panel). Then, when the user clicks the add button, you create a new creation panel and add it to the container been used to display them, for example...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
JButton btnAdd = new JButton("+");
setLayout(new BorderLayout());
JPanel buttons = new JPanel(new FlowLayout(FlowLayout.LEFT));
buttons.add(btnAdd);
add(buttons, BorderLayout.NORTH);
JPanel content = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.weighty = 1;
content.add(new JPanel(), gbc);
add(new JScrollPane(content));
btnAdd.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
CreationPane pane = new CreationPane();
int insertAt = Math.max(0, content.getComponentCount() - 1);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.weightx = 1;
content.add(pane, gbc, insertAt);
content.revalidate();
content.repaint();
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public static class CreationPane extends JPanel {
private static int count;
public CreationPane() {
setLayout(new GridBagLayout());
add(new JLabel("Make it so " + (count++)));
setBorder(new CompoundBorder(new LineBorder(Color.BLACK), new EmptyBorder(10, 10, 10, 10)));
}
}
}
Now having done all that, I prefer the VerticalLayout manager from SwingLabs, SwingX library, which basically does the same thing...

Close Gps on BoxLayout

I have created a setup of buttons using Box.
The problem is there are gaps between all the buttons.
Below is an MCVE version of my code. What I want to achieve is that the buttons "ONE" and "TWO" are touching side by side, with no gap, and buttons "ONE and "ONE" are touching top to bottom with no gap, and for this to continue throughout the setup.
I have read about glue and have tried to use it, but I have not been able to work it out. I am not able to use another layout other than Box as it will not fit in with the rest of my project.
public class Customers {
public static JFrame frame = new JFrame();
public static void frameGui(JPanel panel, String name){
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(panel);
frame.setSize(1200,500);
frame.setVisible(true);
}
public static void ScrollCustomersGui(){
Box box = Box.createVerticalBox();
box.add(customersTableHeadings(box));
box.add(customersTableHeadings(box));
box.add(customersTableHeadings(box));
box.add(customersTableHeadings(box));
JScrollPane scroll = new JScrollPane(box);
JPanel All = new JPanel(new BorderLayout());
All.add(scroll);
frameGui(All, "Customers");
}
public static JPanel customersTableHeadings(Box panel){
Font font = new Font("Courier", Font.BOLD,12);
JPanel customersTable = new JPanel();
JButton custid = new JButton("ONE");
JButton surname = new JButton("TWO");
customersTable.add(custid);
customersTable.add(surname);
return customersTable;
}
}

BoxLayout is designed to distribute unused space among components; struts, glue and filler won't change this. You can use the approach suggested here and here to alter the preferred size of the enclosing scroll pane. More generally, you can implement the scrollable interface. In addition, Swing GUI objects should be constructed and manipulated only on the event dispatch thread.
import java.awt.Dimension;
import java.awt.EventQueue;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
/** #se https://stackoverflow.com/a/26829171/230513 */
public class Customers {
private static final int N = 16;
private void display() {
Box box = Box.createVerticalBox();
for (int i = 0; i < N; i++) {
box.add(customersTableHeadings());
}
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new JScrollPane(box) {
int w = box.getPreferredSize().width;
int h = box.getPreferredSize().height;
#Override
public Dimension getPreferredSize() {
return new Dimension(9 * w / 8, h / 3);
}
});
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private JPanel customersTableHeadings() {
JPanel customersTable = new JPanel();
JButton custid = new JButton("ONE");
JButton surname = new JButton("TWO");
customersTable.add(custid);
customersTable.add(surname);
return customersTable;
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
new Customers().display();
});
}
}

I found the answer myself. By adding the horizontal and vertical inside the same loop, and by enclosing this in a JApplet it closes the gap.
Below is a full working version of the code:
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import javax.swing.Box;
import javax.swing.JApplet;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class Box1 extends JApplet {
public void init() {
Box bv = Box.createVerticalBox();
box(bv);
JScrollPane scroll = new JScrollPane(bv);
JPanel All = new JPanel(new BorderLayout());
All.add(scroll);
Container cp = getContentPane();
cp.add(All);
}
public static void main(String[] args) {
frameGui(new Box1(), "Customers");
}
public static void frameGui (JApplet applet, String name) {
JFrame frame = new JFrame();
frame.getContentPane().removeAll();
frame.setTitle(name);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(applet);
frame.setSize(1200, 500);
applet.init();
applet.start();
frame.setVisible(true);
}
public static Box box(Box boxvert){
for (int i = 0; i < 50; i++){
JTextField one = new JTextField("ONE");
one.setMaximumSize(new Dimension (150,20));
JTextField two = new JTextField("TWO");
two.setMaximumSize(new Dimension (150,20));
Box horizontalBox = Box.createHorizontalBox();
horizontalBox.add(one);
horizontalBox.add(two);
boxvert.add(horizontalBox);
}
return boxvert;
}
}

Scrolling to the top JPanel inside a JScrollPane

I know a lot of people asked this question, but i still can't resolve this problem.
I have a JPanel inside a JScrollPane. JPanel contains six panels that are loaded dynamically.
After the panels are loaded the system makes a vertical autoscroll to the middle of the panel.
I have to avoid this, so I tried with this:
panel.scrollRectToVisible(scrollPane.getBounds());
But it doesn't work.
My scrollPane has been created in this way
JScrollPane scrollPane= new JScrollPane();
scrollPane.setBounds(panel.getBounds());
scrollPane.setViewportView(panel);
Can you help me?

panel.scrollRectToVisible(scrollPane.getBounds()); should be panel.scrollRectToVisible(JPanelAddedOnRuntime.getBounds());
rest of code (posted here) coudn't be works,
for better help sooner post an SSCCE, short, runnable, compilable
EDIT
works, again you would need to re_read my above 3rd. point
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.util.Vector;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class ScrollTesting {
private JPanel panel = new JPanel();
private JScrollPane scrollPane = new JScrollPane(panel);
private Vector<JTextField> fieldsVector = new Vector<JTextField>();
private Dimension preferredSize = new Dimension(400, 40);
private Font font = new Font("Tahoma", 1, 28);
public ScrollTesting() {
panel.setLayout(new GridLayout(100, 1));
for (int i = 0; i < 100; i++) {
fieldsVector.addElement(new JTextField());
fieldsVector.lastElement().setPreferredSize(preferredSize);
fieldsVector.lastElement().setFont(font);
panel.add(fieldsVector.lastElement());
}
JFrame frame = new JFrame();
frame.setSize(400, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(scrollPane);
frame.setVisible(true);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JTextField tf = (JTextField) fieldsVector.lastElement();
panel.scrollRectToVisible(tf.getBounds());
}
});
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
ScrollTesting scrollTesting = new ScrollTesting();
}
});
}
}