Getting strings from JTextArea into variables

[TheGadgetCat]

So, I'm working on a little program for myself that takes a picture of the screen at specific coordinates and then outputs the picture in a .jpg

I have it working taking a picture of the whole screen, but I wanted it to be able to be more specific by creating JTextAreas in a GridLayout and then having the strings entered in them being converted into integers and expressed as a,b,c,d which would then feed into the capture coordinates.

Here is what I have so far:

import java.awt.AWTException;
import java.awt.BorderLayout;
import java.awt.ComponentOrientation;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.HeadlessException;
import java.awt.Robot;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.*;

import javax.imageio.ImageIO;
import javax.swing.*;

public class ScreenCap implements ActionListener{
	
	//Create frame and button and text fields
	int a,b,c,d;
	
	JFrame frame; 
	JButton button;
	JTextField t1,t2,t3,t4;
	
	//Create the Grid Layout
	
	public final static boolean RIGHT_TO_LEFT = false;
	
	public static void addComponentsToPane(Container contentPane){
		
		if(RIGHT_TO_LEFT){
			contentPane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
		}
		
		contentPane.setLayout(new GridLayout(0,2));
		
		contentPane.add(new JTextField("W Coordinate"));
		contentPane.add(new JTextField("X Coordinate"));
		contentPane.add(new JTextField("Y Coordinate"));
		contentPane.add(new JTextField("Z Coordinate"));
	}
	
	//Create and define frame and button
	public void go(){
		frame = new JFrame();
		button = new JButton("Capture Screen");
		t1 = new JTextField("W Coordinate");
		t2 = new JTextField("X Coordinate");
		t3 = new JTextField("Y Coordinate");
		t4 = new JTextField("Z Coordinate");
		
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(300,200);
		frame.setVisible(true);
		frame.add(button);
		
		addComponentsToPane(frame.getContentPane());
		
		frame.add(BorderLayout.SOUTH,button);
		
		button.addActionListener(new buttonListener());
		
	}
	//Run the program
	public static void main(String[] args){
		ScreenCap screen = new ScreenCap();
		screen.go();
	}

	//Cap the screen when the button is pressed
	
	 private class buttonListener implements ActionListener{
		public void actionPerformed(ActionEvent e){
			
			BufferedImage screencapture = null;
			try {
				screencapture = new Robot().createScreenCapture(
						new Rectangle(a,b,c,d));
			} catch (HeadlessException e2) {
				// TODO Auto-generated catch block
				e2.printStackTrace();
			} catch (AWTException e2) {
				// TODO Auto-generated catch block
				e2.printStackTrace();
			}
			
			File file = new File("screencapture1.jpg");
			try {
				ImageIO.write(screencapture, "jpg", file);
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			}
	 }
}

I annotated it so you can see where the class is that takes the capture and where the GridLayout is created ETC.

All help is appreciated!

[quad64bit]

Do you have a specific question/problem? You have a good start so far.

[TheGadgetCat]

Yea, the problem is that I don't know how to get the strings that the user would enter into the text boxes to be converted to integers and used in the coordinates for the screen capture.

I guess I wasn't too clear about that an I apologize...

[quad64bit]

Its ok. You can read the value of a textfield, which returns a String. From here, try

int n = Integer.parseInt(someString);

You can repeat this for each textfield. Does that help?

[TheGadgetCat]

Ok, that's going to be helpful, but how do I read the string, that seems to be the first logical step that I am having trouble with.

[quad64bit]

Take a look at the API page for JTextField. You'll note it has methods for returning the contents of the field :D

[TheGadgetCat]

Ok I think I found it, thanks a bunch!

[TheGadgetCat]

Well maybe not.

this is my new code:

import java.awt.AWTException;
import java.awt.BorderLayout;
import java.awt.ComponentOrientation;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.HeadlessException;
import java.awt.Robot;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.*;

import javax.imageio.ImageIO;
import javax.swing.*;

public class ScreenCap implements ActionListener{
	
	//Create frame and button and text fields
	
	JFrame frame; 
	JButton button;
	JTextField t1,t2,t3,t4;
	
	//Create the Grid Layout
	
	public final static boolean RIGHT_TO_LEFT = false;
	
	public static void addComponentsToPane(Container contentPane){
		
		if(RIGHT_TO_LEFT){
			contentPane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
		}
		
		contentPane.setLayout(new GridLayout(0,2));
		
		contentPane.add(new JTextField("W Coordinate"));
		contentPane.add(new JTextField("X Coordinate"));
		contentPane.add(new JTextField("Y Coordinate"));
		contentPane.add(new JTextField("Z Coordinate"));
	}
	
	//Create and define frame and button
	public void go(){
		frame = new JFrame();
		button = new JButton("Capture Screen");
		t1 = new JTextField("W Coordinate");
		t2 = new JTextField("X Coordinate");
		t3 = new JTextField("Y Coordinate");
		t4 = new JTextField("Z Coordinate");
		
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(300,200);
		frame.setVisible(true);
		frame.add(button);
		
		addComponentsToPane(frame.getContentPane());
		
		frame.add(BorderLayout.SOUTH,button);
		
		button.addActionListener(new buttonListener());
		
		
	}
	//Run the program
	public static void main(String[] args){
		ScreenCap screen = new ScreenCap();
		screen.go();
	}

	//Cap the screen when the button is pressed
	
	 private class buttonListener implements ActionListener{
		public void actionPerformed(ActionEvent e){
			
			String w = t1.getText();
			String x = t2.getText();
			String y = t3.getText();
			String z = t4.getText();
			
			int a = Integer.parseInt(w);
			int b = Integer.parseInt(x);
			int c = Integer.parseInt(y);
			int d = Integer.parseInt(z);
			
			
			BufferedImage screencapture = null;
			try {
				screencapture = new Robot().createScreenCapture(
						new Rectangle(a,b,c,d));
			} catch (HeadlessException e2) {
				// TODO Auto-generated catch block
				e2.printStackTrace();
			} catch (AWTException e2) {
				// TODO Auto-generated catch block
				e2.printStackTrace();
			}
			
			File file = new File("screencapture1.jpg");
			try {
				ImageIO.write(screencapture, "jpg", file);
			} catch (IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			}
	 }
}

What is different is that after the button is pressed, I have Java get the text from all of those text fields, and then convert them into integers.

At least that is the plan.

This is what I get from the console on output:

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "W Coordinate"
at java.lang.NumberFormatException.forInputString(Unk nown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at ScreenCap$buttonListener.actionPerformed(ScreenCap .java:82)
at javax.swing.AbstractButton.fireActionPerformed(Unk nown Source)
at javax.swing.AbstractButton$Handler.actionPerformed (Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed (Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseRe leased(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(U nknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unkno wn 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.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(U nknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

From what I can see, at line 82, which is:

int a = Integer.parseInt(w);
int b = Integer.parseInt(x);
int c = Integer.parseInt(y);
int d = Integer.parseInt(z);

It begins to stop working, I don't really know what to do. Looks to me like it isn't refreshing the text fields and it still thinks that the string is "W Coordinate" instead of the value 100 which I put in when I ran the program.

Do I have to place this somewhere else in the code?

[mastal]

You have to rewrite your addComponentsToPane method couse you're adding there new JTextField objects, not the ones you created in go() method :)

Sorry for my english ;)

[TheGadgetCat]

I don't think that it needs to be written into the addComponentsToPane method because all that does is set up the grid layout. It needs to be written into the go function or maybe the actionEvent because I need the program to get the new strings that the user has entered and then convert them to integers for use in the actionEvent when the button is pressed.

I need Java to refresh the strings so it recognizes that the user changed the value in the JTextArea to something other than "W Coordinate."

It is changing it to an integer, but not recognizing the new string I enter.

[mine0926]

What is your textfields' value?

[TheGadgetCat]

The text fields each have a parameter of "W Coordinate" - "Z Coordinate" which is the default string that they show when they appear on the frame.

[Fubarable]

The text fields each have a parameter of "W Coordinate" - "Z Coordinate" which is the default string that they show when they appear on the frame.

Perhaps you want to put this text in a JLabel next to the JTextField and not in the JTextField itself. Otherwise if you put it in the JTextField, you'll have to take care to delete it before trying to parse the text in the field, which should seem kind of obvious.

[TheGadgetCat]

That would make sense, but the problem still remains that the program isn't sending the updated string to the conversion to an integer, meaning that even if the string was blank, it would just send a blank string to the conversion to integer, meaning that the problem still wouldn't be solved. I could be wrong, and I love to be wrong, so please prove me wrong.

Thanks for all of your help in troubleshooting this by the way.

[Fubarable]

Heck, you're not even adding the JTextFields that you're checking to the GUI. You're adding new JTextFields that have no relationship to the t1, t2,... fields:

		//   **** you're creating completely unrelated JTextFields here!
		contentPane.add(new JTextField("W Coordinate"));
		contentPane.add(new JTextField("X Coordinate"));
		contentPane.add(new JTextField("Y Coordinate"));
		contentPane.add(new JTextField("Z Coordinate"));
	}
	
	//Create and define frame and button
	public void go(){
		frame = new JFrame();
		button = new JButton("Capture Screen");
		t1 = new JTextField("W Coordinate"); //  ***** these guys are never added to the GUI!!
		t2 = new JTextField("X Coordinate");
		t3 = new JTextField("Y Coordinate");
		t4 = new JTextField("Z Coordinate");

[Fubarable]

Also, your variable names should be smarter than the ones you are using and should make so much sense that your code becomes self-documenting.

[TheGadgetCat]

I realize that as this is a learning experience, I should really learn to make the code a bit more organized, and I think that will be the next step.

But I got it to work!

I got the JTextAreas in the right places as you mentioned and then moved the String getText and parseInt to the button's Action Event and now it is working flawlessly!

I just need to add some labels to make it a little nicer, and get the code cleaned up and annotated.

I appreciate all of your help, and I really learned a lot from this. Thanks a bunch!

[milovan]

it is always good to learn something new, take a look at this code for some ideas
import java.awt.AWTException;
import java.awt.BorderLayout;
import java.awt.ComponentOrientation;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.HeadlessException;
import java.awt.Robot;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.*;

import javax.imageio.ImageIO;
import javax.swing.*;

public class ScreenCap { // remark: no need for ActionListener implementation here

//Create frame and button and text fields

JFrame frame;
JButton button;
JTextField t1,t2,t3,t4;

//Create the Grid Layout

// remark: in my case no need for this
public final static boolean RIGHT_TO_LEFT = false;

/* remark: i see no need for this method so i didn't use it
*
* the fact is that by using this method you always put these:
* new JTextField("W Coordinate")... newly created components
* on screen and when user changes its value it doesn't affect
* value of t1, t2... components so they keep their original values:
* "W Coordinate", "X Coordinate"...
*
* So when you ask for String values of t1, t2... latter in your actionPerrformed() method
* you will always get "W Coordinate" and so on...
*/

public static void addComponentsToPane(Container contentPane){

if(RIGHT_TO_LEFT){
contentPane.setComponentOrientation(ComponentOrien tation.RIGHT_TO_LEFT);
}

contentPane.setLayout(new GridLayout(0,2));

contentPane.add(new JTextField("W Coordinate"));
contentPane.add(new JTextField("X Coordinate"));
contentPane.add(new JTextField("Y Coordinate"));
contentPane.add(new JTextField("Z Coordinate"));
}

//Create and define frame and button
public void go(){
frame = new JFrame();
button = new JButton("Capture Screen");

// remark: why not to add actionListener here
button.addActionListener(new buttonListener());
t1 = new JTextField("W Coordinate");
t2 = new JTextField("X Coordinate");
t3 = new JTextField("Y Coordinate");
t4 = new JTextField("Z Coordinate");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOS E);
frame.setSize(300,200);

// remark: sets the layout of frame in one way or another, you choose...
frame.setLayout(new GridLayout(5,1));
//frame.setLayout(new GridLayout(1,5));

// remark: adding components to frame
frame.add(t1);
frame.add(t2);
frame.add(t3);
frame.add(t4);
frame.add(button);

// remark: always set visible at the end when everything is added
frame.setVisible(true);
}
//Run the program
public static void main(String[] args){
ScreenCap screen = new ScreenCap();
screen.go();
}

//Cap the screen when the button is pressed

private class buttonListener implements ActionListener{
public void actionPerformed(ActionEvent e){

/* remark: in case user entered a letter instead of number you will get
* java.lang.NumberFormatException.
* to avoid your app crash you can use try - catch block
* in that case you need to declare int variables out of
* try - catch block so they can be used latter
*/
int a = 0;
int b = 0;
int c = 1;
int d = 1;

try{

String w = t1.getText();
String x = t2.getText();
String y = t3.getText();
String z = t4.getText();

a = Integer.parseInt(w);
b = Integer.parseInt(x);
c = Integer.parseInt(y);
d = Integer.parseInt(z);
// and more apropriate way is to put these into one line of code:
// a = Integer.parsInt(t1.getText());
// b = ...
}
catch(java.lang.NumberFormatException nfe){
System.out.println("you must enter a number");
}

BufferedImage screencapture = null;
try {
screencapture = new Robot().createScreenCapture(
new Rectangle(a,b,c,d));
} catch (HeadlessException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
} catch (AWTException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}

File file = new File("screencapture1.jpg");
try {
ImageIO.write(screencapture, "jpg", file);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
}