Image display within GridBagLayout Java

Question

My image is passed into my program from a server and saved as a string. I want to convert that string into an image, and then in turn display that image within a label inside of a GridBagLayout. When I execute the below code, I get a blank frame. No exceptions during execution. When I look at the image object from the ToolKit in debug, it does say height and width are -1 (but the "imagedata" within the "source = ByteArrayImageSource" has byte[5144]). Any ideas?

Added Note: Image is stored in program as a String because the data is serialized in C# and is being deserialized within Java. This process apparently does not like byte[] in the deserialize process so I save it as a string and use getBytes when I want to use the image.

imageToDisplay = Toolkit.getDefaultToolkit().createImage(myString.getBytes());
ImageIcon logoIcon = new ImageIcon(imageToDisplay);
JLabel logolabel = new JLabel(logoIcon);
     mainPanel.add(logolabel, new GridBagConstraints(0, 0, 1, 1, 1.0, 1.0,
       GridBagConstraints.EAST, GridBagConstraints.HORIZONTAL, 
       new Insets(2, 2, 2, 2), 0, 0));
     mainFrame.add(mainPanel, new GridBagConstraints(0, 0, 1, 1, 1.0, 1.0,
       GridBagConstraints.CENTER, GridBagConstraints.BOTH, 
       new Insets(2, 2, 2, 2), 0, 0));

Answer 1

First you need to find out if the problem is the image or the layout. Do mmyers suggestion and place it a panel (possibly by itself) with a FlowLayout. If it still doesn't show up, it might the image. Is there a reason why the input is converted to a String? The default charset may not be able to handle the conversion cleanly (that is, bytes -> String -> bytes may not give you the same initial bytes).

Answer 2

you should always give an explicit encoding when converting a String to bytes, since the default value is platform dependent.

Using ISO-8859-1 will work in most cases, since that encoding maps the bytes 0 to 255 to the characters U+0000 to U+00FF.

Of course, you have to make sure that the data did not get mangled when you converted them to a String in C# (you can give an encoding there as well...).

Answer 3

Turns out this was my own fault. There is nothing wrong with the code I have written above other than I forgot to decode the image string. It is passed from the server Base64 encoded, and I was using getBytes on that encoded string and passing that into the "createImage" function. Thanks for your suggestions and help. The correct code is below:

try 
{
     imageToDisplay = Toolkit.getDefaultToolkit().createImage(Base64.decode(myString));
} catch (Exception e1) {
     //   // TODO Auto-generated catch block
     e1.printStackTrace();
}

ImageIcon logoIcon = new ImageIcon(imageToDisplay);
JLabel logolabel = new JLabel(logoIcon);
mainPanel.add(logolabel, new GridBagConstraints(0, 0, 1, 1, 1.0, 1.0,
    GridBagConstraints.EAST, GridBagConstraints.HORIZONTAL, 
    new Insets(2, 2, 2, 2), 0, 0));