Display random images from folder to JLabel in Netbeans

问题

My project contains a folder named images containing images. I want to display the images randomly to the JLabel in the frame when a button pressed. I tried the code below:

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt)
 {
    Image im=new ImageIcon(this.getClass().getResource("/images/a1.jpg")).getImage();
    ImageIcon iconLogo = new ImageIcon(im);
    jLabel2.setIcon(iconLogo);
 }

This code displays only the image a1. But I need the images randomly (one image at a time).

回答1:

Use something like

..getResource("/images/a" + randomNumber + ".jpg")

Genderate a random number for randomNumber variable. As long as all your images have the same prefix and just different numerical suffix, you should be fine.

---

If they're all different, then store each string path into a String array and the random number will be the index

getResource("/images/" + pathArray[randomNumber])

Example

String[] imageNames {"hello.jpg", "world.png", "!.gif"};
Random rand = rand = new Random();
....
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt)
{
    int index = rand.nextInt(3);

    Image im=new ImageIcon(this.getClass()
                .getResource("/images/" + imageNames[index])).getImage();
    ImageIcon iconLogo = new ImageIcon(im);
    jLabel2.setIcon(iconLogo);
}

---

UPDATE to OP comment

"Oh!if the folder contains 100 pictures it seems very difficult.My project needs more images"

then load the filed names into a data structure via the File API.. file.list() <-- return a String[]

File file = new File("src/images");
String[] imageNames = file.list(); 
...
int index = rand.nextInt(imagNames.length);

As long as all the files are files and not directories, this should work fine.

---

UPDATE

As discussed below in the comments, its been noted that the above answer will probably not work at time of deployment. Here is @AndrewThompson's suggestion as a fix to the file problem

The best way I can think of is:

1. Create a small helper class that creates a list of the images.
2. Write that list to a File, one name per line.
3. Include the file as a resource (the easiest place is where the images are).
4. Use getResource(String) to gain an URL to it.
5. Read it back in at run-time.

来源：https://stackoverflow.com/questions/21060810/display-random-images-from-folder-to-jlabel-in-netbeans