I've been working with GWT for awhile, I can't find a way to integrate it with a preexisting website which is a real downer. My page content is already generated for me using jsp, like:
<div id='A'></div>
<div id='B'></div>
etc.
there is no way for me to do something like this though:
public void onModuleLoad() {
SimplePanel spA = new SimplePanel(
Document.getElementById("A"));
spA.add(new Label("hello"));
SimplePanel spB = new SimplePanel(
Document.getElementById("B"));
spB.setWidth("200px");
etc ..
}
seems like there's no way to just wrap a pre-existing element. Is this true, or am I missing how to do this? I need be able to wrap a bunch of elements like this, to manipulate them later on. I see TextBox, Button, a few other classes have wrap() methods, however nothing like that exists for elements,
Thanks
There is a way to wrap existing DOM elements, like Label's wrap() method. For example:
Label label = Label.wrap(DOM.getElementById("A"));
label.setText("Foo!");
Other GWT classes can wrap DOM elements too, like Button, and CheckBox using its constructor.
Use HTMLPanel:
class MyPanel extends HTMLPanel {
private SimplePanel a = new SimplePanel();
private SimplePanel b = new SimplePanel();
public MyPanel() {
super("<div id="a"></div><div id="b"></div>);
addAndReplaceElement(a, "a");
addAndReplaceElement(b, "b");
}
}
Related
Edit
Since no one has responded to my original question I think it is worthwhile adding a description of what I am attempting to accomplish, in addition to the existing description of how I have attempted to achieve my goal:
My objective is to create a DataGrid that will resize according to any change in size of its container. This is not difficult to do, but I have an additional requirement, which is to have Panel widgets above and below the DataGrid; these two Panel widgets will contain widgets that are fixed in size (e.g., a row of buttons or text input widgets). My expectation was that a HeaderPanel would be perfect for this, but this doesn't seem to work (as can be seen in my original question, below). So ... an alternative to my original question ("why doesn't this work") is: what is the best way to implement this requirement?
My original question:
I have a DataGrid in the content area of a HeaderPanel, but the detail lines in the DataGrid are not being displayed (the DataGrid column headings are showing, however). Is there an issue with using a DataGrid in the content area of a HeaderPanel? Or is this a simple misuse of the widgets? I'm adding the HeaderPanel to the RootLayoutPanel, which should provide the necessary resize notification (I think). Here is my UiBinder code:
<ui:UiBinder
xmlns:ui='urn:ui:com.google.gwt.uibinder'
xmlns:g='urn:import:com.google.gwt.user.client.ui'
xmlns:c='urn:import:com.google.gwt.user.cellview.client'>
<g:HeaderPanel>
<g:SimplePanel/>
<g:ResizeLayoutPanel>
<c:DataGrid ui:field='dataGrid'/>
</g:ResizeLayoutPanel>
<g:HorizontalPanel>
<g:Button
ui:field='addRecordButton'
text='Add Record'/>
<g:Label ui:field='numberOfRecordsLabel'/>
</g:HorizontalPanel>
</g:HeaderPanel>
</ui:UiBinder>
and here is the Java code:
public class TempGWT implements EntryPoint {
#UiField
Button addRecordButton;
#UiField
DataGrid<Record> dataGrid;
#UiField
Label numberOfRecordsLabel;
private ArrayList<Record> _recordList;
interface TempGWTBinder extends UiBinder<Widget, TempGWT> {
}
private static class Record {
private String _field1;
}
#Override
public void onModuleLoad() {
_recordList = new ArrayList<Record>();
TempGWTBinder binder = GWT.create(TempGWTBinder.class);
Widget widget = binder.createAndBindUi(this);
Column<Record, String> field1Column = new Column<Record, String>(new TextInputCell()) {
#Override
public String getValue(final Record record) {
return record._field1;
}
};
dataGrid.addColumn(field1Column, "Field 1");
RootLayoutPanel.get().add(widget);
}
#UiHandler("addRecordButton")
public void onAddRecordButtonClick(final ClickEvent event) {
Record record = new Record();
record._field1 = "Record " + (_recordList.size() + 1);
_recordList.add(record);
dataGrid.setRowData(_recordList);
numberOfRecordsLabel.setText("Records:" + _recordList.size());
}
}
I've attempted to trace the execution and, although I'm not certain, it looks as though the following happens when I change the size of the browser window and the "resize" request is received by the DataGrid (I've skipped some of the "unimportant" methods):
DataGrid#onResize
HeaderPanel#forceLayout
ScrollPanel#onResize
The DataGrid object contains a HeaderPanel, which contains the headings for the DataGrid and a ScrollPanel. I don't know whether this is the key to the problem, but the ScrollPanel in the DataGrid's HeaderPanel contains a DataGrid$TableWidget object, and TableWidget does not implement RequiresResize; the ScrollPanel#onResize method only sends the resize to its child if the child implements RequiresResize.
The Tables and Frames section of the GWT Developer's Guide makes it clear that I just needed to use a width/height of 100% for the DataGrid! Like so:
<c:DataGrid
ui:field='dataGrid'
width='100%'
height='100%'/>
I am having a GWT app,
I would like to add ID to each element automaticlly
if it's impossible, what would be the fastest way to do it manually?
I am not so sure about performance issues. How would adding a dew ids in a form of 10-20 widgets cause performance loss?
To automagically set debug ids on widgets you need to include following in your module.gwt.xml file.
<!-- Enable debug ID. -->
<inherits name="com.google.gwt.user.Debug"/>
<set-property name="gwt.enableDebugId" value="true"/>
You can create your own Widget class that extends GWT Widget and sets an id to each one:
public class myWidget extends Widget {
public myWidget(String id) {
super();
getElement().setId("id");
}
public void setId(String id) {
// Use this method if you use Ui:Binder
getElement().setId("id");
}
}
You can, obviously, extend other classes instead of Widget if you don't need id on all widgets, like FlowPanel, Button, etc.
If you want to have an element to have an Id always, you can go with ensureDebugId of UI Object class. It make sure that, your element have an Id set before attaching it to the dom.
Yes its Possible :
First way:
Button b = new Button();
DOM.setElementAttribute(b.getElement(), "id", "my-button-id")
Second way :
FlowPanel panel = new FlowPanel();
panel.getElement().setId("my-flowpanel-id");
If you want to do assign all the id's attached to DOM you can do
Iterator<Widget> iterator = RootPanel.get().iterator();
while(iterator.hasNext()) {
Widget w = iterator.next();
w.getElement().setId("id");
}
I'm using a GWT library (gwt-openlayers) which allows me to create a map popup containing arbitrary HTML, similar to Google Maps. I need this HTML to contain a GWT Button widget.
I'm creating some HTML elements on-the-fly like this:
Element outerDiv = DOM.createDiv();
outerDiv.getStyle().setOverflow(Overflow.HIDDEN);
outerDiv.getStyle().setWidth(100, Unit.PCT);
outerDiv.appendChild(new HTML(mapPOI.getHtmlDetails()).getElement());
Button popupButton = new Button("View Property");
popupButton.getElement().getStyle().setFloat(com.google.gwt.dom.client.Style.Float.RIGHT);
outerDiv.appendChild(popupButton.getElement());
Then I'm getting the source HTML for these elements by calling
String src = outerDiv.toString();
and inserting this html into my map marker. Now my map marker displays the content ok, including the button. However, the button won't respond to any events! From what I can gather, this is because the buttons onAttach() method is never being called.
Is there a better way to do this?
Thanks,
Jon
~~~~EDIT~~~~
I'm now trying a new way of doing this, which seems to be the accepted method looking at other similar posts.
First I'm creating my div:
String divId = "popup-" + ref;
String innerHTML = "<div id=\"" +divId + "\"></div>";
Then I'm adding this to my map popup and displaying it (which adds it to the DOM). After the popup has been displayed, I'm getting the Element as follows and trying to wrap a HTMLPanel around it:
Element element = Document.get().getElementById(divId);
HTMLPanel popupHTML = HTMLPanel.wrap(element);
My div element is successfully retrieved. However, HTMLPanel.wrap(element); doesn't complete. The reason for this is that wrap(..) calls RootPanel.detachOnWindowClose(Widget widget), which includes the following assertions:
assert !widgetsToDetach.contains(widget) : "detachOnUnload() called twice "
+ "for the same widget";
assert !isElementChildOfWidget(widget.getElement()) : "A widget that has "
+ "an existing parent widget may not be added to the detach list";
I put some breakpoints in and it seems that the 2nd assertion is failing!
Does anybody have any idea why this might be the case? Should failing this assertion really result in a complete failure of the method (no return)?
Your first approach is good, you just need to register onClick event for your button like this:
DOM.sinkEvents(popupButton.getElement(), Event.ONCLICK);
DOM.setEventListener(popupButton.getElement(), new EventListener() {
#Override
public void onBrowserEvent(Event event) {
//implement the logic after click
}
});
I have checked this, it works 100%!
You might try something like
RootPanel.get("idOfYourMapMarker").add(popupButton);
See RootPanel.get()
Unfortunately, RootPanels are AbsolutePanels which aren't so nice for layout but could work if you just have a simple button to add. You could also try RootLayoutPanel which will give you a LayoutPanel (also not so nice when you just want things to flow). You might end up creating a container widget that does the layout for you, and adding that to the RootPanel.
SimplePanel is a DIV. Perhaps that can be used instead?
You added the element, but you have to keep the hierarchy of the actual GWT Widgets too.
I don't see a clean way to do this, but you could use something like jQuery to grab the button by and ID and add a click handler back to it that would call the original click handler.
private static native void registerEvents(String buttonId, MyClass instance)/*-{
var $ = $wnd.$;
//check click
$('#'+buttonId).live('click', function(e) {
e.preventDefault();
instance.#com.package.MyClass::handleButtonClick(Lcom/google/gwt/event/dom/client/ClickEvent;)(null);
});
}-*/;
Call this registerEvents() either in your onAttach or constructor.
I once had a similar problem. You can use the gwt-openlayer's MapWidget as follows:
private MapWidget createMapWidget() {
final MapOptions defaultMapOptions = new MapOptions();
defaultMapOptions.setDisplayProjection(DEFAULT_PROJECTION);
defaultMapOptions.setNumZoomLevels(TOTAL_ZOOM_LEVELS);
MapWidget mapWidget = new MapWidget(MAP_WIDGET_WIDTH, MAP_WIDGET_HEIGHT, defaultMapOptions);
map = mapWidget.getMap();
return mapWidget;
}
And then add it to any panel be it vertical or horizontal.
MapWidget mapWgt = createMapWidget();
VerticalPanel mainPanel = new VerticalPanel();
mainPanel.add(mapWgt);
...
... add whatever you want
...
You can finally add the created Panel(containing the MapWidget and the gwt widget) to the PopupPanel. Also, you should now be able to add handlers to the gwt button.
I'd like to use the following in UIBinder, so that I can programmatically set the href of the link in my code.
<g:HTMLPanel>
<g:Anchor ui:field="link">
<g:InlineLabel ui:field="firstName"/>
<g:InlineLabel ui:field="lastName"/>
</g:Anchor>
</g:HTMLPanel>
When I try this I get:
ERROR: Found widget in an HTML context Element <g:InlineLabel ui:field='firstName'> (:7).
How can I embed widgets inside an anchor? Previously I've resorted to using:
<a id="myAnchor">
etc...
</a>
And then manipulating the DOM in my code to set the HREF, but that's ugly. Is there a better way?
The class below acts exactly like a SimplePanel (i.e., you can put an widget in it), but uses an "a" instead of a "div". If you need more widgets just put another panel in it.
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.ui.SimplePanel;
public class Link extends SimplePanel {
public Link() {
super(DOM.createAnchor());
}
private void setHref(String href) {
getElement().setAttribute("href", href);
}
private String getHref() {
return getElement().getAttribute("href");
}
public void setTarget(String frameName) {
getElement().setAttribute("target", frameName);
}
}
It is better to use a Panel (Flow or Horizontal) and add click handlers to the panel to simulate a link. Anchor, Button and similar widgets will not allow child tags inside them.
lets say i have a custom widget which has a ClickHandler. Here's the example:
public class TestWidget extends Composite {
private static TestWidgetUiBinder uiBinder = GWT
.create(TestWidgetUiBinder.class);
interface TestWidgetUiBinder extends UiBinder<Widget, TestWidget> {
}
#UiField
Button button;
public TestWidget(String firstName) {
initWidget(uiBinder.createAndBindUi(this));
button.setText(firstName);
}
#UiHandler("button")
void onClick(ClickEvent e) {
Window.alert("Hello!");
}
}
When i try to add this Widget like this:
TestWidget testWidget = new TestWidget("myTestWidget");
RootPanel.get().add(testWidget);
everything is fine. If i click on my button i get the message i expect.
However if i add it like this:
TestWidget testWidget = new TestWidget("myTestWidget");
RootPanel.getBodyElement().appendChild(testWidget.getElement());
my click event is not being fired. I'm struggeling to understand why.
It would be nice if someone could explain this to me or link me to an resource where i can read this up. Finally i would like to know if it is possible to add the clickhandler afterwards i appended the child event and if that way is recommended. Thanks it advance for help.
kuku
When you call add(), Widget.onAttach() is called on the widget that is being added to the panel. onAttach does some work to register the widget to receive events. appendChild() simply attaches one DOM element to another and does nothing else. You should be able to get events working in the second case by doing this:
Element element = testWidget.getElement();
RootPanel.getBodyElement().appendChild(element);
DOM.sinkEvents(element,
Event.getTypeInt(ClickEvent.getType().getName())
| DOM.getEventsSunk(element);
However, I haven't tested this and I wouldn't recommend that you use it in a real application. Using add() is definitely preferred, using appendChild() in this way has no advantages and may lead to unexpected behaviour.