Thread: Is there a way to make things happen if a certain text is entered in a TextField?

Hey,

First of all please excuse my lack of technical terms.

I want to have a JTextField be able to accept commands, and have the commands change pictures, display text etc.

Is their a simple way to do this?

Thanks in advance,

-Duster

(If you need the code, just ask)

Originally Posted by DusteroftheCentury

Hey,

First of all please excuse my lack of technical terms.

I want to have a JTextField be able to accept commands, and have the commands change pictures, display text etc.

Is their a simple way to do this?

Thanks in advance,

-Duster

(If you need the code, just ask)

I would suggest reading java docs GUI tutorials and methods that fall into that concept. Try something that comes to your mind, if you fail, try again and then post errors you receive here.

300zek0.pngThis image might help better explain what I want:

Originally Posted by elisha.java

I would suggest reading java docs GUI tutorials and methods that fall into that concept. Try something that comes to your mind, if you fail, try again and then post errors you receive here.

Didnt see your post there. I shall try.

Here is my code so far:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
 
public class MainClass extends JFrame implements ActionListener
{
	public static void main(String[] args)
	{
		new MainClass();
	}
		private JButton button1;
		private JLabel label1;
		private JTextField textbox1;
 
		public MainClass()
		{
		JPanel panel1 = new JPanel();
		{
		button1 = new JButton("OK");
		ButtonListener b1 = new ButtonListener();
		JLabel label1 = new JLabel();
		JTextField textbox1 = new JTextField(15);
		textbox1.getText();
		textbox1.addActionListener(this);
 
		panel1.add(textbox1);
		panel1.add(label1);
		panel1.add(button1);	
 
		this.add(panel1);
		this.setSize(300,100);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setVisible(true);
	}
}
 
	private class ButtonListener implements ActionListener
	{
	public void ActionPerformed1(ActionEvent e)
	{
		if (e.getSource() == button1);
		{
 
			if (e.getSource() == button1);
			//Code to check if the command the commands goes here?
			}
		}
	}
 
	public void ActionPerformed2(ActionEvent f)
	{
		if (f.getSource() == textbox1);
		{
 
			if (f.getSource() == textbox1);
				//Or here? 
			}
	}		
}

Am I heading in the right direction? I checked the Java docs GUI tuts and from what I could gather this is where I should be going.

In the places where i specified where the code might go what code would I put in there? The Gui docs tut just shows how to add the ActionListener, not how to use it.

Thanks for the help,

-Duster

I just want it to add a pic to the panel by using ImageIcon. This is the image: PBn'J.gif

How would I listen to the actions? I know I can do "textbox1.getText();" to retrieve the text, but what code do I add to make it listen to that text and check if it is a command?

Also where would it go?

Thanks for your help,

-Duster

I appreciate this but I understand that spoon feeding is bad. I only needed a few lines of that and that is what I will use.

Thank you.

@copeg I understand, I accidentally spoon fed someone this morning, before I knew it was wrong.

-Duster

-_-, i never thought of a GIF image -_-, i was thinking you want to create the sprites and animation manually, well there you go.

I really dont want to just use the code given, I want to figure it out with help.

Here is my new code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JFrame;
 
public class MainClass extends JFrame 
{
	public static void main(String[] args)
	{
		new MainClass();
	}
 
		private JLabel label1;
		private JTextField textbox1;
 
		public MainClass()
		{
		JPanel panel1 = new JPanel();
		{
 
		JLabel label1 = new JLabel();
		JTextField textbox1 = new JTextField(15);
		textbox1.getText();
		textbox1.setToolTipText("Enter commands");
 
		panel1.add(textbox1);
		panel1.add(label1);
 
 
 
		this.add(panel1);
		this.setSize(300,100);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setVisible(true);
	}
}
 
 
	public void ActionPerformed2(ActionEvent f)
	{
		if (textbox1.getText().toString().equals("banana"))
			{
			JFrame frame1 = new JFrame();
			frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			ImageIcon pic = new ImageIcon(MainClass.class.getResource("PBn'J.gif"));
			frame1.add(new JLabel(pic));
 
		}		
	}
}

When I type "banana" and hit enter, nothing happens. No errors messages either. Do I need to add an action listener? if so, how would I do that in this instance?

Thanks for helping

-Duster

@moderator

I sorry for what i did . Actually i am new to this forum and some of the post i have seen others providing solution using code snippets ...So that's why i did ..

But if i will not provide snippets, how would i able to give my solution ? If you recommend suggestion in terms of providing links and some comments, So its just become a long thread of a clarification/queries chain and just the wastage of time.

Personally i do believe in open source ethics "share and learn".

Thanks, I checked the link and touched up on ActionListeners. I wrote this code,

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JFrame;
 
public class MainClass extends JFrame implements ActionListener
{
	public static void main(String[] args)
	{
		new MainClass();
	}
 
		private JLabel label1;
		private JTextField textbox1;
		private JButton button1;
 
		public MainClass()
		{
		JPanel panel1 = new JPanel();
		{
 
		JLabel label1 = new JLabel();
		JTextField textbox1 = new JTextField(15);
		textbox1.getText();
		textbox1.addActionListener(this);
		textbox1.setToolTipText("Whats the password?");
		button1 = new JButton("OK");
		button1.addActionListener(this);
 
		panel1.add(textbox1);
		panel1.add(button1);
		panel1.add(label1);
 
 
 
		this.add(panel1);
		this.setSize(300,100);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setVisible(true);
	}
}
 
 
	public void actionPerformed(ActionEvent e)
	{
		if (e.getSource() == button1)
			{
			if (textbox1.getText().equals("password"))
				System.out.println("You sir are a good guesser.");
 
		}		
	}
}

And it produces this error message:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at MainClass.actionPerformed(MainClass.java:48)
	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.awt.Component.processMouseEvent(Unknown Source)
	at javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.awt.Component.processEvent(Unknown Source)
	at java.awt.Container.processEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$000(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)

Please help, not sure what is wrong with my code.

Thanks,

-Duster

Could you explain what null means? And what kind of printlns? I know they can be used to catch exceptions but how?

Thanks for the help,

-Duster

What lines of code would you reccomend checking? And how? I understand your blog, but I do not see how that would apply here, because I dont really use numbers and integers and such, which if I did I would know how to check. However I dont know how to check text variables.

Thanks for helping a beginner,

-Duster

It prints this:

javax.swing.JTextField[,0,0,0x0,invalid,layout=javax.swing.plaf.basic.BasicTextUI$UpdateHandler,alignmentX=0.0,alignmentY=0.0,border=javax.swing.plaf.BorderUIResource$CompoundBorderUIResource@25b80053,flags=296,maximumSize=,minimumSize=,preferredSize=,caretColor=sun.swing.PrintColorUIResource[r=51,g=51,b=51],disabledTextColor=javax.swing.plaf.ColorUIResource[r=184,g=207,b=229],editable=true,margin=javax.swing.plaf.InsetsUIResource[top=0,left=0,bottom=0,right=0],selectedTextColor=sun.swing.PrintColorUIResource[r=51,g=51,b=51],selectionColor=javax.swing.plaf.ColorUIResource[r=184,g=207,b=229],columns=15,columnWidth=0,command=,horizontalAlignment=LEADING]

Thanks for helping,

-Duster

Originally Posted by DusteroftheCentury

It prints this:

javax.swing.JTextField[,0,0,0x0,invalid,layout=javax.swing.plaf.basic.BasicTextUI$UpdateHandler,alignmentX=0.0,alignmentY=0.0,border=javax.swing.plaf.BorderUIResource$CompoundBorderUIResource@25b80053,flags=296,maximumSize=,minimumSize=,preferredSize=,caretColor=sun.swing.PrintColorUIResource[r=51,g=51,b=51],disabledTextColor=javax.swing.plaf.ColorUIResource[r=184,g=207,b=229],editable=true,margin=javax.swing.plaf.InsetsUIResource[top=0,left=0,bottom=0,right=0],selectedTextColor=sun.swing.PrintColorUIResource[r=51,g=51,b=51],selectionColor=javax.swing.plaf.ColorUIResource[r=184,g=207,b=229],columns=15,columnWidth=0,command=,horizontalAlignment=LEADING]

Thanks for helping,

-Duster

NO. In your previous last given code, you have actually declared textbox1 as instance variable and then in constructor, you re-declare and initialize it as a local variable, so the instance variable is actually shadowed but still null. Just remove the declaration inside the constructor and the code will work fine.

What line do I remove? Sorry Im just not very familiar with the many technical terms.

Thank you so much,

-Duster

JTextField textbox1 = new JTextField(15);

Instead of this, just write

textbox1 = new JTextField(15);