vaadin-framework/src/com/itmill/toolkit/terminal/gwt/client/ui/IUpload.java

package com.itmill.toolkit.terminal.gwt.client.ui;

import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.ClickListener;
import com.google.gwt.user.client.ui.FileUpload;
import com.google.gwt.user.client.ui.FlowPanel;
import com.google.gwt.user.client.ui.FormHandler;
import com.google.gwt.user.client.ui.FormPanel;
import com.google.gwt.user.client.ui.FormSubmitCompleteEvent;
import com.google.gwt.user.client.ui.FormSubmitEvent;
import com.google.gwt.user.client.ui.Panel;
import com.google.gwt.user.client.ui.Widget;
import com.itmill.toolkit.terminal.gwt.client.ApplicationConnection;
import com.itmill.toolkit.terminal.gwt.client.Paintable;
import com.itmill.toolkit.terminal.gwt.client.UIDL;

public class IUpload extends FormPanel implements Paintable, ClickListener,
		FormHandler {

	/**
	 * FileUpload component that opens native OS dialog to select file.
	 */
	FileUpload fu = new FileUpload();

	Panel panel = new FlowPanel();

	ApplicationConnection client;

	private String paintableId;

	/**
	 * Button that initiates uploading
	 */
	private Button b;

	/**
	 * When expecting big files, programmer may initiate some UI changes when
	 * uploading the file starts. Bit after submitting file we'll visit the
	 * server to check possible changes.
	 */
	private Timer t;

	/**
	 * some browsers tries to send form twice if submit is called in button
	 * click handler, some don't submit at all without it, so we need to track
	 * if form is already being submitted
	 */
	private boolean submitted = false;

	public IUpload() {
		super();
		setEncoding(FormPanel.ENCODING_MULTIPART);
		setMethod(FormPanel.METHOD_POST);

		setWidget(panel);
		panel.add(fu);
		// TODO
		b = new Button("Click to Upload");
		b.addClickListener(this);
		panel.add(b);

		addFormHandler(this);
	}

	public void updateFromUIDL(UIDL uidl, ApplicationConnection client) {
		this.client = client;
		this.paintableId = uidl.getId();
		setAction(client.getAppUri());

		if (uidl.hasAttribute("caption"))
			b.setText(uidl.getStringAttribute("caption"));
		fu.setName(paintableId + "_file");

	}

	public void onClick(Widget sender) {
		this.submit();
	}

	public void onSubmit(FormSubmitEvent event) {
		if (fu.getFilename().length() == 0 || submitted) {
			event.setCancelled(true);
			ApplicationConnection.getConsole().log(
					"Submit cancelled (no file or already submitted)");
			return;
		}
		submitted = true;
		ApplicationConnection.getConsole().log("Submitted form");

		disableUpload();

		/*
		 * visit server after upload to see possible changes from UploadStarted
		 * event
		 */
		t = new Timer() {
			public void run() {
				client.sendPendingVariableChanges();
			}
		};
		t.schedule(800);
	}

	protected void disableUpload() {
		b.setEnabled(false);
		fu.setVisible(false);
	}

	protected void enableUploaod() {
		b.setEnabled(true);
		fu.setVisible(true);
	}

	public void onSubmitComplete(FormSubmitCompleteEvent event) {
		if (client != null) {
			if (t != null)
				t.cancel();
			ApplicationConnection.getConsole().log("Submit complete");
			client.sendPendingVariableChanges();
		}
		submitted = false;
		enableUploaod();
	}

}