I'd like to put a custom listener on the scrollbar of the viewport layer to trigger other code whenever the scrollbar is moved. I currently extended the HorizontalScrollBarHandler and overrode the handleEvent() method. The handler needs to take in the scrollbar from the ViewportLayer, but unfortunately it's private and has no getter method. Is there any other way that I can access the scrollbar to use with my custom handler?
NatTable is a Canvas which is a Scrollable. So actually you should not try to do deal with internals. It should be possible to call natTable.getVerticalBar() and natTable.getHorizontalBar() to register your listener.
Alternatively you could implement your own IScroller as explained here: http://blog.vogella.com/2015/01/26/nattable-with-custom-scrollbars/
But just for adding a listener it should be sufficient to use default SWT mechanisms.
Related
I am developing a GWT Web application and I would like to include the resize capability into the container. For that, I am implementing a combination of Vertical and Horizontal Panels within a FlowPanel which is resizable. Well, the code for the resize method is the following:
Window.addResizeHandler(new ResizeHandler() {
#Override
public void onResize(ResizeEvent event) {
flowPanel.setHeight(event.getHeight()+"px");
flowPanel.setWidth(event.getWidth()+"px");
}
});
However, when I change the size of the windows, the size of the web elements does not change. Do you know how to implement it?
Thank you very much in advance!!!
You may want to review your layout solution. There are very few cases when you need to use a ResizeHandler. Typically, you can achieve a desired layout either by using a LayoutPanel (or Horizontal/Vertical panels) that automatically resize with the window, or by using CSS. Then your layout will respond well to any changes in a browser window, and you don't need to write any code for that to happen.
EDIT:
In order for a widget to resize automatically, the parent widget must implement ProvidesResize, and the child widget must implement Resizable. FlowPanel does not implement either. Once you use it, the chain of resizing events is broken.
Typically, I use a LayoutPanel for my outmost container. It occupies the entire browser window when added to the RootPanel, and it adjusts with the Window. Vertical and Horizontal panels are similar.
use,
window.getClientWidth();
window.getClientHeight();
Based on your component size you can -/+ px and use.
I want to put a complex layout with text-fields and operation buttons for each cell in a CellList. So I want to put a GWT panel to organize the widgets.
Is it possible to put gwt panels and widgets in CellList? I tried to extend AbstractCell and override render(). But seems only HTML can be rendered. I didn't find a way to render normal gwt panels and widgets.
CompositeCell seems going through List> automatically, you can not arrange widget as you wish. Also, I don't know whether normal widgets like PushButton can be used in CompositedCell.
Please give me a sample if you tried this before? Thanks a lot.
It is not possible to put GWT widgets or Panels in a CellWidgets.
CellWidgets are designed for rapid rendering of large amounts of data.
If you don't have that use case you can still use a FlexTable.
Otherwise you have to create a CompositeCell or AbstractCell and implement the render and event handling methods yourself.
I'm trying to insert a gwt datagrid in my application. If i set a static height (500px) everything works nice. But i want to make the dataGrid auto adjust to screen size. With height 100% i get a blank screen.
i've also tried to put the datagrid into a resizeLayoutPanel with the same results.
any tips?
All RequiresResize widgets should be given an explicit size, or be added to ProvidesResize widgets (up to a RootLayoutPanel or a ProvidesResize widget with an explicit size; the only exception is ResizeLayoutPanel which doesn't implement ProvidesResize because it couldn't honor the contract for its header and footer widgets, but it definitely honors it for the center widget).
So the question is: where did you add your DataGrid and/or ResizeLayoutPanel?
Thomas Broyer is correct. Nonetheless I found something of interest concerning the DataGrid (it does not happen in CellTable).
If you are using a DeckPanel and if you are creating the DataGrid on a hidden Panel of this DeckPanel, than the data of the DataGrid will not be visible if you show the panel of the DataGrid.
I found only one workaround: call addDataDisplay of your DataProvider "after" the panel was made visible.
How would I override events e.g. OnmouseOver, OnMouseOut in extended widgets?
I am trying to extend the Anchor widget and want to set a certain stylename from my CSS.
In this case you could add handlers in you constructor via addMouseOverHandler and addMouseOutHandler and the handlers add/remove your stylenames.
Another option is to override the OnBrowserEvent(Event event) method on catch the mouse over and mouse out events.
However, mouse out events won't work perfect in all browsers. Sometimes the mouse out event is not triggered on the widget and you're style will stay on the widget. If you want to set style on a widget you could also add a yourstylename:hover in you're style sheet, such that you let the browser do the work of adding and removing the stylenames.
Using GWT 2.0 I have an entry point that adds two Widgets to a LayoutPanel which in turn is added to the RootLayoutPanel. The Widgets both handle click events and have click events registered to them. The problem is that only the last widget added to the LayoutPanel can actually be clicked. Switch the order in which the widgets are added switches the widget that works. Add mroe widgets and still the only you can click is the last one added to the LayoutPanel.
Any idea why this is? Is there any reasoning behind the behaviour, or have I missunderstood what is happening under the covers? How do I gat all widgets in the LayoutPanel to accept events? Should I be using another panel class?
I'm not too bothered if the LayoutPanel prevents anything below it from being clicked, but want all Widgets added to it to be clickable.
Stupid Boy! (said in the voice of Captain Mainwaring)
There is no problem having two Widgets on a LayoutPanel accepting clicks. But if you adjust the Widgets' size by manipulating their elements' styles directly then the containing element created by the LayoutPanel will still cover the whole screen. In effect the last Widget added always covered everything else.
GWT school: D- Must try harder. Easily distracted...