How to detect if a Popup is showing

[Craig Mitchell]

Hi,

I wanted to check if a popup is showing, so I wrote this method:

public static int getNumPopupsShowing() {

int result = 0;

NodeList<Element> divs = Document.get().getElementsByTagName("div");

for (int i=0; i<divs.getLength(); i++) {

if ("gwt-PopupPanel".equals(divs.getItem(i).getClassName())) {

result++;

}

}

return result;

}

However, is there a better way?

Thanks.

[ashwin....@gmail.com]

Popup Panels have a isShowing() method, use that to determine if its currently displayed

~Ashwin

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[Craig Mitchell]

Thanks Ashwin.  Yes, sorry, should have been a little more clear, I wanted to detect if a popup is showing, "which I didn't already have the reference to".

Apologies for not being more clear.

[dreamer]

Not sure, if there is a automatic way of detecting all child windows
to a parent window on demand,
but certainly you can main maintain, global array list and every popup
window that you open, and
call close on each of those. You can lot of examples in javascript -
"closing child windows to idea".

[Thomas Broyer]

PopupPanels append themselves to RootPanel.get(), so you can loop over RootPanel.get().getChildren() and whenever you see a PopupPanel you can ask if it isShowing().

[Craig Mitchell]

Thanks Thomas.  Much cleaner that way!

New code:

/**

 * @return the number of modal popups currently showing

 */

public static int getNumPopupsShowing() {

int result = 0;

for (int i=0; i<RootPanel.get().getWidgetCount(); i++) {

Widget widget = RootPanel.get().getWidget(i);

if (widget instanceof PopupPanel

&& ((PopupPanel)widget).isShowing()

&& ((PopupPanel)widget).isModal()) {

result++;

}

}

return result;

}

I actually thought this wouldn't work when compiled, because I didn't know how it would tell which div was a popup panel, but somehow it does!  Go GWT!

[Thomas Broyer]

Any reason you don't use an "enhanced for loop"? for (Widget widget : RootPanel.get().getChildren()) { ... }

It works because it's looping on widgets, not elements (look at the code, there's an ArrayList<Widget> to store the child widgets; there's no magic)

[Craig Mitchell]

getChildren() doesn't exist (in GWT 2.2.0).  However, I could have used RootPanel.get().iterator().

I would have thought when GWT compiled the widgets, they would turn into a <div> or something similar, and their type would be lost, however, I'm clearly wrong, as it works a treat!

[Craig Mitchell]

Sorry, getChildren() does exist, however, it's a protected method.

[Thomas Broyer]

Oh right, sorry, missed the 'protected' keyword in the javadoc. Note however that HasWidgets extends Iterable<Widget> (hence the existence of RootPanel.get().iterator()) so you could write "for (Widget w : RootPanel.get()) { ... }" (not sure I like it though)