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GMap custom widget [message #643766]

Wed, 08 December 2010 08:40

Yury Mising name

Messages: 95
Registered: May 2010
Location: Russia

Member

Hi, All!

I'm developing my own custom widget and get some problem. I'd tried to reproduce this problem on your GMap widget from your CVS and it had been reproduced!
I've added the GMap on the dialog:

  public int createUI() {
    Display display = PlatformUI.createDisplay();
    Shell shell = new Shell(display);
    shell.setLayout( new FillLayout() );
 
    GMap map = new GMap( shell, SWT.NONE );
    map.setAddress( "Stephanienstraße 20, Karlsruhe" );

    shell.setSize(300, 300);
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
    return 0;
  }

And everything seems to work fine, but I'm interesting in the following: set the breakpoint to this method into GMapLCA.java and try to resize the dialog

  public void readData( final Widget widget ) {
    GMap map = ( GMap )widget;
    String location = WidgetLCAUtil.readPropertyValue( map, PARAM_CENTER );
    map.setCenterLocation( location );
  }

WidgetLCAUtil.readPropertyValue( map, PARAM_CENTER ) returns NULL after resizing and our widget will have null value for it's location parameter. It is because there are no PARAM_CENTER in the current request. And i don't have an answer for a question - why?
Could you get any explanation?

Best regards,
Yury.

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Re: GMap custom widget [message #643789 is a reply to message #643766]

Wed, 08 December 2010 09:45

Tim Buschtoens

Messages: 396
Registered: July 2009

Senior Member

Hi Yury!

> WidgetLCAUtil.readPropertyValue( map, PARAM_CENTER ) returns NULL after
> resizing and our widget will have null value for it's location
> parameter. It is because there are no PARAM_CENTER in the current
> request. And i don't have an answer for a question - why?

It seems you found a bug. The code should actually be:

public void readData( final Widget widget ) {
GMap map = ( GMap )widget;
String location = WidgetLCAUtil.readPropertyValue( map, PARAM_CENTER );
if( location != null ) {
map.setCenterLocation( location );
}
}

When readPropertyValue returns null, it indicated that the value hasnt
changed, therfore no changes will be made to the widget.

Hope that helps.

Gretings,
Tim

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Re: GMap custom widget [message #643807 is a reply to message #643789]

Wed, 08 December 2010 11:13

Yury Mising name

Messages: 95
Registered: May 2010
Location: Russia

Member

Hi, Tim!

Actually I've already made this fixes that you propose Smile

But just interesting about correctness of this fixes, maybe anyone propose another way to fix them. Anyway, thank you for help!

Best regards,
Yury.

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Re: GMap custom widget [message #644180 is a reply to message #643807]

Thu, 09 December 2010 18:22

Ivan Furnadjiev

Messages: 2426
Registered: July 2009
Location: Sofia, Bulgaria

Senior Member

Hi Yury,
all widgets LCA are visited on every request. In xxxLCA#readData() you
check if a specific for the widget parameter (property) exists in the
request and process it if exist. That's why the null check after you get
a property is absolutely obligatory. The request contains only "changed"
properties.
HTH,
Ivan

On 08.12.2010 1:13 PM, Yury wrote:
> Hi, Tim!
>
> Actually I've already made this fixes that you propose :) But just
> interesting about correctness of this fixes, maybe anyone propose
> another way to fix them. Anyway, thank you for help!
>
> Best regards,
> Yury.

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