GWT 2.1 Data Presentation Widgets without paging - gwt

Question

I am trying to build a table with large dataset and would like to avoid paging. (I would like to do something similar to Yahoo Mail grid which retrieves data after the grid is drawn. I think initially the first 100 mails are retrieved and then mail is only retrieved after the user scrolls down)
The example of the data presentation widget I have seen include paging. Is it possible to do what I want?
edit: You could also call this an infinite scroll table

Answer 1

There are an exemple of this in the GWT Showcase
/**
* A scrolling pager that automatically increases the range every time the
* scroll bar reaches the bottom.
*/
public class ShowMorePagerPanel extends AbstractPager {
/**
* The default increment size.
*/
private static final int DEFAULT_INCREMENT = 20;
/**
* The increment size.
*/
private int incrementSize = DEFAULT_INCREMENT;
/**
* The last scroll position.
*/
private int lastScrollPos = 0;
/**
* The scrollable panel.
*/
private final ScrollPanel scrollable = new ScrollPanel();
/**
* Construct a new {#link ShowMorePagerPanel}.
*/
public ShowMorePagerPanel() {
initWidget(scrollable);
// Handle scroll events.
scrollable.addScrollHandler(new ScrollHandler() {
public void onScroll(ScrollEvent event) {
// If scrolling up, ignore the event.
int oldScrollPos = lastScrollPos;
lastScrollPos = scrollable.getScrollPosition();
if (oldScrollPos >= lastScrollPos) {
return;
}
HasRows display = getDisplay();
if (display == null) {
return;
}
int maxScrollTop = scrollable.getWidget().getOffsetHeight()
- scrollable.getOffsetHeight();
if (lastScrollPos >= maxScrollTop) {
// We are near the end, so increase the page size.
int newPageSize = Math.min(
display.getVisibleRange().getLength() + incrementSize,
display.getRowCount());
display.setVisibleRange(0, newPageSize);
}
}
});
}
/**
* Get the number of rows by which the range is increased when the scrollbar
* reaches the bottom.
*
* #return the increment size
*/
public int getIncrementSize() {
return incrementSize;
}
#Override
public void setDisplay(HasRows display) {
assert display instanceof Widget : "display must extend Widget";
scrollable.setWidget((Widget) display);
super.setDisplay(display);
}
/**
* Set the number of rows by which the range is increased when the scrollbar
* reaches the bottom.
*
* #param incrementSize the incremental number of rows
*/
public void setIncrementSize(int incrementSize) {
this.incrementSize = incrementSize;
}
#Override
protected void onRangeOrRowCountChanged() {
}
}

Answer 2

Dean already mentioned Ext GWT but I'd like to suggest SmartGWT's implementation as well.

Answer 3

Yes, it is possible. There used to be an example of that called DynaGrid here but that link is dead now. I haven't been able to find it anywhere else (note: that's not the same as the DynaGrid on SourceForge). You might be able to contact the author, Reinier Zwitserloot, to inquire about getting a copy of his DynaGrid. You could also search the GWT Group and if you don't find anything, post there asking if anyone else knows where to find it.

Answer 4

Ext Gwt (AKA GXT) has an implementation of a "Live Grid" that supports this functionality (see http://www.sencha.com/examples/explorer.html#livegrid). The code is GPL although you can buy a license to use this in commercial applications.