ZK Developer's Reference/UI Patterns/Event Threads/File Upload

This documentation is for an older version of ZK. For the latest one, please click here.

File Upload with Servlet Thread

When the event thread is disable (default), it is recommended to use Button or Toolbarbutton with upload="true" instead. For example,

<zk>
	<zscript>
	void upload(UploadEvent event) {
		org.zkoss.util.media.Media media = event.getMedia();
		if (media instanceof org.zkoss.image.Image) {
			org.zkoss.zul.Image image = new org.zkoss.zul.Image();
			image.setContent(media);
			image.setParent(pics);
		} else {
			Messagebox.show("Not an image: "+media, "Error", Messagebox.OK, Messagebox.ERROR);
			break; //not to show too many errors
		}
	}
	</zscript>
	<button label="Upload" upload="true" onUpload="upload(event)"/>
	<toolbarbutton label="Upload" upload="true" onUpload="upload(event)"/>
	<vbox id="pics" />
</zk>

If you prefer to use a dialog (Fileupload.get()), please take a look at ZK Component Reference: Fileupload for more inormation.

File Upload with Event Thread

If the event thread is disabled, the developer can use Button or Toolbarbutton with upload="true" instead. They behaves the same no matter the event thread is disabled or not.

However, if the event thread is disabled, it is convenient to use Fileupload.get() and other static methods.

<zk>
	<button label="Upload">
	<attribute name="onClick">{
		org.zkoss.util.media.Media[] media = Fileupload.get(-1);
		if (media != null) {
			for (int i = 0; i &lt; media.length; i++) {
				if (media[i] instanceof org.zkoss.image.Image) {
					org.zkoss.zul.Image image = new org.zkoss.zul.Image();
					image.setContent(media[i]);
					image.setParent(pics);
				} else {
					Messagebox.show("Not an image: "+media[i], "Error", Messagebox.OK, Messagebox.ERROR);
					break; //not to show too many errors
				}
			}
		}
	}</attribute>
	</button>
	<vbox id="pics" />
</zk>

As shown, Fileupload.get(int) won't return until the end user uploads the files (and/or closes the dialog).