What is the correct path to display an ImageIcon png file for Windows 7?

Question

I wanted to test having a program with a simple png image on it. I wrote a short program that does this, but I can't seem to get the path right. I have checked, checked again, rechecked, and quadruple checked my path name as to not get it right, but this image will not display, no matter what I do. I used a short class wrote by Oracle in the ImageIcon documentation (the creaetImageIcon()) to accomplish this, but it doesn't seem to help. I'll post the entire program below, as it is very short.

package practiceImages;

import java.awt.BorderLayout;
import java.awt.Toolkit;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class ImageIconGUITest {

    public static void main(String[] args) {
        ImageIconGUITest gui = new ImageIconGUITest();
        gui.display();
    }

    private ImageIcon createImageIcon(String path, String description) {
        java.net.URL imgURL = getClass().getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL, description);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }

    private void display() {
        JFrame frame = new JFrame();
        JLabel label = new JLabel(createImageIcon(
                "Users/Evan/javaItems/Sprites_and_Other_Art/green.png", "the color green"));

        frame.add(BorderLayout.CENTER, label);
        frame.setSize(500, 500);
        frame.setVisible(true);
    }
}

Solution 1

The getResource(String) method will only find resources that are on the run-time class-path of the application. Since this image seems like an application resource (i.e. supplied by you as part of the application) it should be put on the run-time class-path.

E.G. Most IDEs have a place you can put resources within the project structure, that will automatically be included at run-time. Move (or copy) the image to that path.

Then it becomes a matter of providing the correct String. Let us imagine your project is set up something like this:

• bin
• src
  1. com
     • our
       1. Application.java
  2. resources
     • green.png

So Application.java is in package com.our;, while the image is in the path resources/green.png.

If accessing the image from the Application, the correct path would be (drum roll please..)

"/resources/green.png"

Notes

1. The leading / is important. It tells the JRE we want to look for the image from the 'root of the class-path', as opposed to using a path relative to the package of the class itself.
2. Correct case is also vital. A string of "/resources/green.png" will not locate an image named "/resources/Green.png" or "/resources/green.PNG".

Eclipse paths

1. Right click on the src directory, select Properties at the bottom of the menu.
   
2. Navigate (using the normal way you'd use without Eclipse) to the directory of the Location.
3. Then go to the parent directory.
4. You should see a bin directory that contains classes and (hopefully) the image.

Solution 2

Firstly, you've supplied a relative path, so the system is looking for the image relative to the location you executed the program.

Secondly, the path should have a drive spec or at least a leading /. Depending on your setup, something like 'C:/Users/Evan/javaItems/Sprites_and_Other_Art/green.png' should work (you may need to change the drive spec to meet your system)

Thirdly, make sure that the file exists in the specified location, System.out.println(new File("C:/Users/Evan/javaItems/Sprites_and_Other_Art/green.png").exists()) should return true, other wise the file is in the wrong location.

A relative path basically means a path location relative to the programs execution. So, if you were running the program from C:/Program Files/MyAwesomeApplication for example, a relative path of Users/Evan/javaItems/Sprites_and_Other_Art/green.png would become an absolute path of C:/Program Files/MyAwesomeApplication/Users/Evan/javaItems/Sprites_and_Other_Art/green.png. This describes the path from the root location to the file/folder in question.

You can test this by using System.out.println(new File("C:/Users/Evan/javaItems/Sprites_and_Other_Art/green.png").getAbsolutePath(‌​)) which will give you the full path.

Comments

[Andrew Thompson]

"make sure that the file exists" +1

[user2398233]

full path gave me C:\Users\Evan\javaItems\Sprites_and_Other_Art\green.png What the heck?

[Andrew Thompson]

@MadProgrammer If you liked that, check out the embedded-resource info. page which me and trashgod have updated to being a very Java specific info. page. ;)

[user2398233]

@MadProgrammer using System.out.println(new File("C:/Users/Evan/javaItems/Sprites_and_Other_Art/green.pn‌​g").getAbsolutePath)‌​) just gave me the same path.

[Andrew Thompson]

"didn't work, but oh well" We'll need more & better information that tha, if we are to have any chance of solving this. E.G. what exact steps did you take to try it? What IDE (if any) is being used? What is the listing of the bin (I think that is the Eclipse runt-time) directory?

[user2398233]

@AndrewThompson Console sent: Couldn't find file: /resources/green.png Did everything you said, read it over a few times, and it seemed logical. Not sure what the hell is going on.

[Andrew Thompson]

"Couldn't find file:" That would be better stated as Couldn't find resource since.. by time of deployment (or possibly after being built) it will no longer be a File so much as an entry in a Jar. You still have not given me the listing of the bin directory. Note that the .java files are in src but the classes (and run-time class-path) is typically in bin. Make sure the image made it to (was copied to) the bin.

[user2398233]

@AndrewThompson What do you mean by "the listing of the bin directory"? I don't know what that means...

[Andrew Thompson]

1) Right click on the src directory. 2) Select Properties at the bottom of the menu. 3) Navigate (using the normal way you'd use without Eclipse) to that directory. 4) Then go to the parent directory. 5) You should see a bin directory..

[user2398233]

@AndrewThompson Step 3: "Navigate (using the normal way you'd use without Eclipse) to that directory." What directory? When I selecte preferences, there's just a Resource and a Run/debug settings tab. I don't know what you're talking about anymore or why I'm doing this?

[MadProgrammer]

@user2398233 Of course it does, that's already an absolute path ;). Try leaving off the C:/ and see what you get ;)

[Andrew Thompson]

"When I selecte preferences" I told you to select Properties. I have expanded my explanation in the edit to answer..

[Andrew Thompson]

Note also: This situation reminds me of why new programmers should not use an 'automagic' IDE. The minute something happens that is not according to plan, leads to complete confusion simply because you've not yet mastered the concepts of run-time and compile time class-paths (and the difference between them). If not the class-path, it will be something else. Maybe you should put the IDE aside for the moment and use a simpler editor (e.g. TextPad) for creating the source.

[user2398233]

@AndrewThompson When I go to the parent folder of the resources folder that I made, that's src. My resources folder, although I put the image into it, can not be opened, presumably because there is nothing in it, even though I put the green.png file into it through my workspace.