Hi!
The problem is that in your function "public void showUsers() {" you
create a entry into FlexTable for each user, including the non-visible
ones.
Some browsers have problems displaying a huge data.
To solve this you have 2 options:
Create some kind of pagination into your flextable, creating a set of
your users and display only the possible visible ones(Something like
50), and remove/add the users as the user navigate through it.
Other option as Tom Hjeliming said, is to use some framework like
SmartGWT(http://code.google.com/p/smartgwt/). SmartGWT have a lot of
features and Widgets that makes life easier.
One of them is the Live Grid(http://www.smartclient.com/smartgwt/
showcase/#featured_grid_live), in the example it have around 700
records, but only render the visible ones, so it runs smooth on IE and
Firefox.
SmartGWT can load only a partial set of the data and ask server for
more when needed or load everything, depends on your requirement.
Regards
On Jun 11, 2:13 pm, Tom Hjellming <[email protected]>
wrote:
> Hi Joe,
>
> The trick is to not even try to load that much data into the browser.
> We use the SmartGWT widget library which has very good support for
> virtual pagination of lists and comboboxes. By default, it only loads
> the first 75 rows and then as the user scrolls down, calls are made back
> to the server to retrieve the desired data - which is then shown to the
> user. There is an occasional delay when the user sees blank space which
> is then filled in when the data comes in. But overall, it is a great
> solution -we're viewing tables with thousands of rows and seeing better
> performance than our old Swing-based application.
>
> Tom
>
>
>
> Joe Larson wrote:
> > I am having a performance problem. I am trying to build a page that
> > allows the user to select from a fairly large list of objects (up to
> > 20,000). We have filtering capabilities to trim the list so the user
> > doesn't have to scroll through all of them. It's a reasonable UI.
>
> > Unfortunately, I only get decent performance on Safari. IE6 is
> > exceptionally miserable. It's okay when the list has 100 items, but
> > it crashes as we exceed 300. So I've been experimenting, and I
> > haven't found a way around it.
>
> > So I created a sample app. All I did was populate an
> > ArrayList<String> with 20,000 fairly short strings that I read out of
> > the HTML file. Under Safari 4 on a G5 Mac Pro, this is almost
> > instant. Under IE6 on a similar age Windows box, it's taking 4
> > minutes. Firefox on the G5 runs out of memory.
>
> > Is it possible to store large amounts of data in my GWT applications?
> > Or do I have to store fairly small amounts of data and go back and
> > forth to the server a lot? If it's the latter, I may as well just go
> > back to what we used to do (WebObjects).
>
> > I'm including my little sample program. Maybe there's something
> > obvious that I can do?
>
> > -Joe
>
> > --- GWTMinimum.java ---
> > package com.missionmode.gwtminimum.client;
>
> > import java.util.*;
>
> > import com.google.gwt.core.client.*;
> > import com.google.gwt.user.client.*;
> > import com.google.gwt.user.client.ui.*;
>
> > /**
> > * Entry point classes define <code>onModuleLoad()</code>.
> > */
> > public class GWTMinimum implements EntryPoint {
> > public FlexTable panel;
> > public Button loadBtn;
> > public Button displayBtn;
> > public ListBox listBox;
> > public Label label;
> > public ArrayList<String> usernames = new ArrayList<String>();
> > public String[] parts;
>
> > /**
> > * This is the entry point method.
> > */
> > public void onModuleLoad() {
> > panel = new FlexTable();
> > RootPanel.get("web2").add(panel);
>
> > loadBtn = new Button("Click to start load");
> > panel.setWidget(0, 0, loadBtn);
>
> > loadBtn.addClickListener(new ClickListener() {
> > public void onClick(Widget sender) {
> > loadUsers();
> > }
> > });
> > }
>
> > /**
> > * We've loaded the user table. Set up so they
> > * can press another button to display the data.
> > */
> > public void setupForDisplay() {
> > displayBtn = new Button("Click to Display");
> > panel.setWidget(0, 1, displayBtn);
> > displayBtn.addClickListener(new ClickListener() {
> > public void onClick(Widget sender) {
> > showUsers();
> > }
> > });
> > }
>
> > /**
> > * Load the users from the HTML page.
> > */
> > public void loadUsers() {
> > if (parts == null) {
> > String str = stringFromDocument("users");
> > parts = str.split("===");
> > loadBtn.setText("Click me again");
> > }
> > else {
> > for (String name : parts) {
> > name = name.trim();
> > if (name.length() > 0) {
> > usernames.add(name);
> > }
> > }
> > showCount();
> > setupForDisplay();
> > }
> > }
>
> > /**
> > * Just show how many users were actually loaded.
> > */
> > public void showCount() {
> > label = new Label("Total user count: " + usernames.size());
> > panel.setWidget(1, 0, label);
> > }
>
> > /**
> > * Show the loaded users.
> > */
> > public void showUsers() {
> > try {
> > listBox = new ListBox();
> > listBox.setVisibleItemCount(20);
> > panel.setWidget(2, 0, listBox);
> > for (String str : usernames) {
> > listBox.addItem(str);
> > }
> > }
> > catch (Exception e) {
> > panel.setText(3, 0, "Error: " + e.getMessage());
> > }
> > }
>
> > /**
> > * Return a string from the document.
> > */
> > public String stringFromDocument(String elementName) {
> > String retVal = "";
> > Element params = DOM.getElementById(elementName);
> > if (params != null) {
> > retVal = DOM.getInnerText(params);
> > }
> > return retVal;
> > }
> > }
>
> > --- Foo.html ---
> > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
> > <html>
> > <head>
> > <meta http-equiv="content-type" content="text/html;
> > charset=UTF-8">
> > <title>GWTMinimum</title>
> > <script type="text/javascript" language="javascript"
> > src="com.missionmode.gwtminimum.GWTMinimum.nocache.js"></script>
> > </head>
> > <body>
> > <div id="web2"></div>
> > <p id="users" style="display: none;">
> > User 0===
> > User 1===
> > User 2===
> > Repeat more users as desired===
> > </p>
> > </body>
> > </html>
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