Showing the uploaded image in Vaadin with EasyUploads - image

Question

I'm trying to use EasyUploads-addon for Vaadin, but can't get the image shown.
When I click addon's "Choose File"-button, it will ask me to open an file. I choose some .png -file from my images and addon shows the information of the picture beneath it.
Then I press my "Upload"-button, which is currently needed just to show the uploaded image at first.
private void showUploadedImage() {
Object value = upload.getValue();
byte[] data = (byte[]) value;
StreamResource resource = new StreamResource(
new StreamResource.StreamSource() {
private static final long serialVersionUID = 1L;
#Override
public InputStream getStream() {
return new ByteArrayInputStream(data);
}
}, "filename.png");
image.setVisible(true);
image.setCaption("Uploaded image");
image.setSource(resource);
}
upload = EasyUpload's component which is used to choose file
image = Embedded component that I have drawn with the designer to my layout.
But when I look the page with browser the image is not shown. The image is just shown as there is no image at all, just caption will be shown.
HTML-code of the image from the page's source:
<img src="null">
This might be really trivial case, but all the examples that I found was over 3-4 years old and didn't look helpful.
Can someone tell me, how it should be done?

Answer 1

You need to call a setter on UploadField class:
uploadField.setFieldType(FieldType.BYTE_ARRAY);
Working SSCCE:
#Override
protected void init(VaadinRequest request) {
setContent(layout);
final UploadField uploadField = new UploadField();
uploadField.setAcceptFilter(".png");
uploadField.setFieldType(FieldType.BYTE_ARRAY);
uploadField.addListener(new Listener(){
#Override
public void componentEvent(Event event)
{
showUploadedImage(uploadField);
}
});
layout.addComponent(uploadField);
layout.addComponent(image);
}
private void showUploadedImage(UploadField upload) {
Object value = upload.getValue();
final byte[] data = (byte[]) value;
StreamResource resource = new StreamResource(
new StreamResource.StreamSource() {
#Override
public InputStream getStream() {
return new ByteArrayInputStream(data);
}
}, "filename.png");
image.setSource(resource);
}
Produces (after choosing a .png file):
Of course you may want to change type of uploadField listener to more specific one.
Tested on Java 8, Vaadin 7.4.1, Eclipse Luna.