I am a java programmer and i want to ask that why is my program not working:
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class Cool extends JFrame{
public void AL(){
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500 , 200);
frame.setVisible(true);
frame.setTitle("Java");
JTextArea textarea = new JTextArea();
textarea.setEditable(false);
textarea.setLineWrap(true);
JTextField field = new JTextField();
field.setText("Hi! This is the text!");
}
}
this is my main class:
#SuppressWarnings("serial")
public class Main {
public static void main(String[] args){
Cool dude = new Cool();
dude.AL();
}
}
It does not display anything just a blank JFrame.It does give the title but nothing else it has everything.
You have to add the JTextArea and the JTextField to the JFrame.
I don't see you adding the widgets to the JFrame, so why should they appear?
frame.add(textarea);
frame.add(field);
You are not adding the JTextArea nor the JTextField to the JFrame. You can do it through the method add which is inherited from Container. According to Java Docs:
Appends the specified component to the end of this container.
Code:
frame.add(textarea);
frame.add(field);
I know there are a good half-dozen answers with the same answer: you should add the elements to your frame. But I also wanted to add that you usually want to encapsulate your JTextArea inside a JScrollPane so that you can write more text that will be shown using scroll bars.
You should also make sure that you're adding your elements to a content pane with a layout manager so that the elements will get arranged in the way that you expect. Take a look at A Visual Guide to Layout Managers to familiarize yourself with the available layout managers. An additional, popular layout manager is MigLayout although it requires an external Jar file.
Below is a simple example with my suggestions:
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
public class Cool extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel contentPane;
private JTextField textField;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Cool frame = new Cool();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Cool() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
textField = new JTextField();
contentPane.add(textField, BorderLayout.NORTH);
textField.setColumns(30);
JScrollPane scrollPane = new JScrollPane();
contentPane.add(scrollPane, BorderLayout.CENTER);
JTextArea txtrImAText = new JTextArea();
txtrImAText.setRows(10);
txtrImAText.setColumns(30);
scrollPane.setViewportView(txtrImAText);
pack();
}
}
You forgot to add the elements to the frame:
frame.add(textarea );
frame.add(field);
Add thise lines and you will see a result.
I haven't used swing, but it seems that you have to add textarea and field to your JFrame frame.
Looking on the net i have seen this example:
frame.getContentPane().add(textarea);
You have to add text area and text field to the JFrame in AL method
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500 , 200);
frame.setVisible(true);
frame.setTitle("Java");
JTextArea textarea = new JTextArea();
textarea.setEditable(false);
textarea.setLineWrap(true);
JTextField field = new JTextField();
field.setText("Hi! This is the text!");
frame.add(textarea); // <-- here
frame.add(field);
Related
I have a JTextArea where I want to allow the user to input any number of strings up to 100 but it could be less. When I set the JTextArea as I have in my code below where it is commented out (i.e. //tfResult= new JTextArea(10, 0);) and the user inputs ten lines of strings then my code runs exactly as expected and prints out what I need it to.
But if I try to input more of less lines I get
java.lang.ArrayIndexOutOfBoundsException
followed by the number of lines of user input, whether I have it declared with no bounds or as I have it commented out.
I am new to graphics in java and I can't figure out why this is happening and I have searched everywhere for answers. Do I have the bounds set wrong or have I declared the JTextArea wrong?
I also am trying to include a JScrollPane but I am having issues with that also as its not showing up.
I would really appreciate any help as I am struggling to solve this issue.
class Window {
JFrame windowFrame;
Panel bottomPanel;
JScrollPane scroll;
JTextArea tfResult;
Button btnPlayAgain;
Font font;
Window(int width, int height, String title)
{
windowFrame = new JFrame();
windowFrame.setTitle(title);
windowFrame.setBounds(0,0,width,height);
windowFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
windowFrame.setResizable(true);
windowFrame.setCursor(new Cursor(Cursor.HAND_CURSOR)); // setting cursor to hand
windowFrame.setLayout(null);
createBottomPanel();
windowFrame.add(bottomPanel);
//windowFrame.add(field.getCanvas());
windowFrame.setVisible(true);
}
private void createBottomPanel()
{
JButton b = new JButton("Compute");
bottomPanel = new Panel();
bottomPanel.setBackground(Color.PINK);
bottomPanel.setBounds(0,400,800,140);
bottomPanel.setLayout(null);
//*********
//tfResult= new JTextArea(10, 0);
tfResult= new JTextArea();
tfResult.setBounds(10,10,600,100);
tfResult.setFont(new Font("SansSerif", Font.BOLD, 16));
tfResult.setFocusable(true);
scroll = new JScrollPane(tfResult);
scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
btnPlayAgain = new Button("Compute");
btnPlayAgain.setBounds(620,10,150,100);
btnPlayAgain.setBackground(Color.RED);
btnPlayAgain.setFont(new Font("SansSerif", Font.BOLD, 24));
btnPlayAgain.setFocusable(true);
bottomPanel.add(tfResult);
bottomPanel.add(btnPlayAgain);
bottomPanel.add(b);
bottomPanel.add(scroll);
tfResult.setVisible(true);
scroll.setVisible(true);
btnPlayAgain.setVisible(true);
bottomPanel.setVisible(true);
btnPlayAgain.addActionListener(new ActionListener()
{
//#Override
public void actionPerformed(ActionEvent e)
{
//should include the code to genrate the output inside here
String input = tfResult.getText();
Mat xy;
xy = new Mat();
//String output = xy.getOutput(input).toString();
String output = xy.getOutput(input);
//String output = Output(input);
tfTarget.setText(output);
}
});
}
}
I went ahead and created the following GUI that allows you to enter data with a JTextArea.
The first thing I did was start my Swing application with a call to the SwingUtilities invokeLater method. This method ensures that the Swing components are created and executed on the Event Dispatch Thread.
Next, I created a JFrame. Then I created a JPanel with a BorderLayout. The JTextArea is inside of a JScrollPane, which is then placed inside of the center of a JPanel.
The JButton is placed after the last line of the JPanel.
Here's the complete runnable code, otherwise known as a minimal runnable example.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class JTextAreaInputGUI implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new JTextAreaInputGUI());
}
private JTextArea textArea;
#Override
public void run() {
JFrame frame = new JFrame("JTextArea Input GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createMainPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createMainPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
textArea = new JTextArea(10, 40);
JScrollPane scrollPane = new JScrollPane(textArea);
panel.add(scrollPane, BorderLayout.CENTER);
JButton button = new JButton("Submit");
button.addActionListener(new ButtonListener());
panel.add(button, BorderLayout.AFTER_LAST_LINE);
return panel;
}
public class ButtonListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent event) {
System.out.println(textArea.getText().trim());
}
}
}
i am writing simple code with GUI that should have one text area which should be scrollable. So far so good.
I created my frame and the text area and i can write in it ok. Next I created my ScrollPane and added the TextArea in it, then added the ScrollPane to the frame but nothing shows.
Here is the code i have at this point:
JFrame frame = new JFrame();
frame.setBounds(100, 100, 325, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
//textArea
JTextArea textArea = new JTextArea();
textArea.setEnabled(true);
textArea.setEditable(true);
JScrollPane scroll = new JScrollPane(textArea,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
textArea.setBounds(10, 101, 272, 149);
textArea.setWrapStyleWord(true);
frame.getContentPane().add(scroll);
change
frame.getContentPane().setLayout(null);
to
frame.getContentPane().setLayout(new BorderLayout());
and you are done
You have to set the bounds to the component that is being added to the content pane of the frame. In this case, it should be: scroll.setBounds(10,101,271,149).
However, I strongly recommend to not use null layout. Use a layout manager of your choice, BorderLayout for instance. In this case you don't have to worry about the bounds, it will fit the frame size (it will resize when you change the size of the frame). Here's your example, tweaked a little bit:
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Test {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setBounds(100, 100, 325, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BorderLayout());
// textArea
JTextArea textArea = new JTextArea();
textArea.setEnabled(true);
textArea.setEditable(true);
JScrollPane scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
textArea.setWrapStyleWord(true);
frame.getContentPane().add(scroll, BorderLayout.CENTER);
frame.setVisible(true);
}
}
I'm still learning however by looking at this case.
I have couple of issues:
There is issue with setting bounds of textArea
Layout of frame/container should not be set to null.
I have removed this sentence, and I tried this code, it displays desired textArea.
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
/*
* Tester class
*/
public class GuiTester extends JFrame{
public static void main(String[] args) {
// create new instance of JFrame
GuiTester s = new GuiTester();
// set the frame to be visible
s.setVisible(true);
}
/**
* Tester constructor calling method which initialise all widgets.
*/
GuiTester() {
//
invokeWidget();
}
/*
* This code is yours, just removed setting up the values of container and did that straight on the frame.
*/
void invokeWidget() {
setBounds(100, 100, 325, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
JTextArea textArea = new JTextArea();
textArea.setEnabled(true);
textArea.setEditable(true);
JScrollPane scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
textArea.setWrapStyleWord(true);
add(scroll);
}
}
This is the line that was causing issues, as well as setting layout Manager to null.
// textArea.setBounds(10, 101, 272, 149);
I hope I helped, and if I'm wrong please correct me as well.
I'm trying to create a scrollable text area, (much like the one i'm writing in right now as in stack overflow's one). It seems as if the scrollpane and the text area are mutually exclusive and i'd like to create a connection between them
package Notepad;
import java.awt.EventQueue;
import java.awt.Font;
import javax.swing.JFrame;
import java.awt.BorderLayout;
import javax.swing.JTextArea;
import javax.swing.JScrollBar;
public class test {
private JFrame frame;
private Font f = new Font(null);
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
test window = new test();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public test() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new BorderLayout(0, 0));
JTextArea textArea = new JTextArea();
frame.getContentPane().add(textArea, BorderLayout.CENTER);
textArea.setLineWrap(true);
textArea.setFont(f.deriveFont(40f));
JScrollBar scrollBar = new JScrollBar();
frame.getContentPane().add(scrollBar, BorderLayout.EAST);
}
}
use JScrollPane rather than JScrollBar
Wrong:
JScrollBar scrollBar = new JScrollBar();
Right:
JScrollPane scroller = new JScrollPane(textArea);
you can set the size of this ScrollPane like so:
Dimension size = new Dimension (0, 50);
scroller.setPreferredSize(size);
NOTE: When you use JScrollPanes, be sure to put where you want it in parentheses, or it will not show up.
JTextArea textArea = new JTextArea();
textArea.setLineWrap(true);
textArea.setFont(f.deriveFont(40f));
JScrollPane scrollPane = new JScrollPane(textArea);
frame.getContentPane().add(scrollPane, BorderLayout.CENTER);
OMG sorry guys. I imported JScrollBar not JScrollPane. Thank you all. I'm going to test this fix and get back to you.
Edit:
It works. Thank you guys!!!
I was trying to make my JTextField fill the width and set a height for it but still failed. I tried adding the code setPreferredSize(new Dimension(320,200)); but still failed. Is there any way I can make my JTextField fill the width and set the height to 200 or something?
You should not play with the height. Let the text field determine the height based on the font used.
If you want to control the width of the text field then you can use
textField.setColumns(...);
to let the text field determine the preferred width.
Or if you want the width to be the entire width of the parent panel then you need to use an appropriate layout. Maybe the NORTH of a BorderLayout.
See the Swing tutorial on Layout Managers for more information.
set the height to 200
Set the Font to a large variant (150+ px). As already mentioned, control the width using columns, and use a layout manager (or constraint) that will respect the preferred width & height.
import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
public class BigTextField {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
// the GUI as seen by the user (without frame)
JPanel gui = new JPanel(new FlowLayout(5));
gui.setBorder(new EmptyBorder(2, 3, 2, 3));
// Create big text fields & add them to the GUI
String s = "Hello!";
JTextField tf1 = new JTextField(s, 1);
Font bigFont = tf1.getFont().deriveFont(Font.PLAIN, 150f);
tf1.setFont(bigFont);
gui.add(tf1);
JTextField tf2 = new JTextField(s, 2);
tf2.setFont(bigFont);
gui.add(tf2);
JTextField tf3 = new JTextField(s, 3);
tf3.setFont(bigFont);
gui.add(tf3);
gui.setBackground(Color.WHITE);
JFrame f = new JFrame("Big Text Fields");
f.add(gui);
// Ensures JVM closes after frame(s) closed and
// all non-daemon threads are finished
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
// See http://stackoverflow.com/a/7143398/418556 for demo.
f.setLocationByPlatform(true);
// ensures the frame is the minimum size it needs to be
// in order display the components within it
f.pack();
// should be done last, to avoid flickering, moving,
// resizing artifacts.
f.setVisible(true);
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
There's a way which maybe not perfect, but can meet your requirement. The main point here is use a special dimension to restrict the height. But at the same time, width actually is free, as the max width is big enough.
package test;
import java.awt.*;
import javax.swing.*;
public final class TestFrame extends Frame{
public TestFrame(){
JPanel p = new JPanel();
p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));
p.setPreferredSize(new Dimension(500, 200));
p.setMaximumSize(new Dimension(10000, 200));
p.add(new JLabel("TEST: "));
JPanel p1 = new JPanel();
p1.setLayout(new BoxLayout(p1, BoxLayout.X_AXIS));
p1.setMaximumSize(new Dimension(10000, 200));
p1.add(new JTextField(50));
p.add(p1);
this.setLayout(new BorderLayout());
this.add(p, BorderLayout.CENTER);
}
//TODO: GUI CREATE
}
xyz.setColumns() method is control the width of TextField.
import java.awt.*;
import javax.swing.*;
class miniproj extends JFrame {
public static void main(String[] args)
{
JFrame frame=new JFrame();
JPanel panel=new JPanel();
frame.setSize(400,400);
frame.setTitle("Registration");
JLabel lablename=new JLabel("Enter your name");
TextField tname=new TextField(30);
tname.setColumns(45);
JLabel lableemail=new JLabel("Enter your Email");
TextField email=new TextField(30);
email.setColumns(45);
JLabel lableaddress=new JLabel("Enter your address");
TextField address=new TextField(30);
address.setColumns(45);
address.setFont(Font.getFont(Font.SERIF));
JLabel lablepass=new JLabel("Enter your password");
TextField pass=new TextField(30);
pass.setColumns(45);
JButton login=new JButton();
JButton create=new JButton();
login.setPreferredSize(new Dimension(90,30));
login.setText("Login");
create.setPreferredSize(new Dimension(90,30));
create.setText("Create");
panel.add(lablename);
panel.add(tname);
panel.add(lableemail);
panel.add(email);
panel.add(lableaddress);
panel.add(address);
panel.add(lablepass);
panel.add(pass);
panel.add(create);
panel.add(login);
frame.add(panel);
frame.setVisible(true);
}
}
What type of LayoutManager are you using for the panel you're adding the JTextField to?
Different layout managers approach sizing elements on them in different ways, some respect SetPreferredSize(), while others will scale the compoenents to fit their container.
See: http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
ps. this has nothing to do with eclipse, its java.
f.setLayout(null);
add the above lines ( f is a JFrame or a Container where you have added the JTestField )
But try to learn 'LayoutManager' in java ; refer to other answers for the links of the tutorials .Or try This http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
maybe applying an EmptyBorder to your JTextField would be the simplest solution to simulate a height, and for the width use the setColumns() method
JTextField input=new JTextField();
input.setColumns(10);
input.setBorder(new EmptyBorder(15,0,15,0);
the 4 arguments of the EmptyBorder constructor are: top, left, bottom and right respectively.
Or if you want something more technical you can override the getPreferredSize, getMinimumSize and getMaximumSize methods so that it returns the values you want to apply as width and height.
JTexField input=new JTextField(){
#Override
public Dimension getPreferredSize(){
return new Dimension(200,40);
};
public Dimension getMinimumSize(){
return new Dimension(200,40);
};
public Dimension getMaximumSize(){
return new Dimension(200,40);
};
};
package myguo;
import javax.swing.*;
public class MyGuo {
JFrame f;
JButton bt1 , bt2 ;
JTextField t1,t2;
JLabel l1,l2;
MyGuo(){
f=new JFrame("LOG IN FORM");
f.setLocation(500,300);
f.setSize(600,500);
f.setLayout(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
l1=new JLabel("NAME");
l1.setBounds(50,70,80,30);
l2=new JLabel("PASSWORD");
l2.setBounds(50,100,80,30);
t1=new JTextField();
t1.setBounds(140, 70, 200,30);
t2=new JTextField();
t2.setBounds(140, 110, 200,30);
bt1 =new JButton("LOG IN");
bt1.setBounds(150,150,80,30);
bt2 =new JButton("CLEAR");
bt2.setBounds(235,150,80,30);
f.add(l1);
f.add(l2);
f.add(t1);
f.add(t2);
f.add(bt1);
f.add(bt2);
f.setVisible(true);
}
public static void main(String[] args) {
MyGuo myGuo = new MyGuo();
}
}
setBounds is working only in BorderLayout use BorderLayout for frame or container or panel and use setBounds to set the width and height of text field.
see this code simple code
import java.awt.*;
import javax.swing.*;
class uni1
{
public static void main(String[] args)
{
JFrame frm = new JFrame();
TextField txt = new TextField();
txt.setBounds(0, 0, 1200, 400);
frm.add(txt,BorderLayout.NORTH);
frm.setLayout(new BorderLayout());
frm.setVisible(true);
frm.setDefaultCloseOperation(frm.EXIT_ON_CLOSE);
}
}
I am working on the editor. I am using Java swing for it. I have embedded a JTextArea with JScrollPane. i want to position the jtextarea of particular size at the middle of JScrollPane. To do this I used setLocation function. But this is not working?
public class ScrollPaneTest extends JFrame {
private Container myCP;
private JTextArea resultsTA;
private JScrollPane scrollPane;
private JPanel jpanel;
public ScrollPaneTest() {
resultsTA = new JTextArea(50,50);
resultsTA.setLocation(100,100);
jpanel=new JPanel(new BorderLayout());
jpanel.add(resultsTA,BorderLayout.CENTER);
scrollPane = new JScrollPane(jpanel,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrollPane.setPreferredSize(new Dimension(800, 800));
scrollPane.setBounds(0, 0, 800, 800);
setSize(800, 800);
setLocation(0, 0);
myCP = this.getContentPane();
myCP.setLayout(new BorderLayout());
myCP.add(scrollPane);
setVisible(true);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
public static void main(String[] args) {
new ScrollPaneTest();
}
}
You simply have to add the JTextArea to the JScrollPane, and add it to the CENTER of the JPanel having BorderLayout.
Don't use AbsolutePositioning. Add a proper LayoutManager, and let LayoutManager do the rest for positioning and sizing your components on the screen.
In order to use the setBounds(...) method you have to use a null Layout for your component, which is not worth using, provided the perspective, as mentioned in the first paragraph of the AbsolutePositioning. Though in the code example provided by you, you are doing both the thingies together i.e. using Layout and using AbsolutePositioning, which is wrong in every way. My advice STOP DOING IT :-)
In the example provided the ROWS and COLUMNS provided by you are sufficient to size the JTextArea by the Layout concern.
Code Example :
import java.awt.*;
import javax.swing.*;
public class Example
{
private JTextArea tarea;
private void displayGUI()
{
JFrame frame = new JFrame("JScrollPane Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new BorderLayout(5, 5));
JScrollPane textScroller = new JScrollPane();
tarea = new JTextArea(30, 30);
textScroller.setViewportView(tarea);
contentPane.add(textScroller);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
new Example().displayGUI();
}
});
}
}