I have an img tag on a wicket page and I add image as following:
NonCachingImage banner = NonCachingImage(id, imageResource)
now i also add attributes like: banner.add(new AttributeModifier("width",...
Now my page constructor is getting invoked twice. If for testing I also add
banner.add(new AttributeModifier("src", new Model<String>("test")
constructor would be invoked only once but the image would not be rendered. Please suggest me how can i render the correct image from org.apache.wicket.Resource and make the constructor getting invoked only once.
Would appreciate if you can direct me to specific examples.
In some browsers, <img> tags that are rendered with src="" (no url) the browser will submit a request to the current url in search of the image. If your imageResource is resolving to an empty url path then this would occur. Further, this would not happen if after creating the NonCachingImage you added an AttributeModifier which would override the generated src attribute with a value of "test" as the value would no longer be empty.
Related
Using Adobe Experience Manager 5.6.1 (AEM) (Formerly CQ5) I am trying to create a new tab similar to the Image tab in Page Properties. It would be titled "Logo".
I basically just copied the Image tab to create a logo tab and renamed the paths to reflect the logo purpose. For instance, I set the fileReferenceParamater to ./logo/fileReference and requestSuffix to /logo.img.png.
When I edit the properties, I can drag an image into the tab just as I can with the "Image" tab, however, the image never appears there. I am guessing this is because the default image handler is not picking up the request. The error is:
Cannot serve request to
/content/my-site/home-page/en_us/jcr:content/logo.img.png in
org.apache.sling.servlets.get.DefaultGetServlet
When I looked at the content node there was no sling:resourceType. When I added a resource type of foundation/components/adaptiveimage then it worked. However, I noticed that the "Image" node didn't have a sling:resourceType. I guess the img.png.java servlet in the foundation page is handling that request.
I tried creating a logo.img.png.jsp file in my page component to handle the request, but that didn't seem to work.
How can I get AEM to either add the sling:resourceType or to handle the request?
I was facing the similar problem and I found a simpler way to resolve. All you need to do is to add a hidden xtype under the your logo image as below:
<yourlogo
jcr:primaryType="cq:Widget"
<-- other properties -->
xtype="html5smartimage">
<items jcr:primaryType="cq:WidgetCollection">
<resType
jcr:primaryType="cq:Widget"
ignoreData="{Boolean}true"
name="./logo/sling:resourceType"
value="foundation/components/image"
xtype="hidden"/>
</items>
</yourlogo>
Well, after some time experimenting, this is what I ended up doing to get this to work. If there is an easier way, I would be happy to know it.
First, I copied the /libs/foundation/components/page/img.png.java file and added it to my compiled package with some modifications.
#SlingServlet(
resourceTypes = "sling/servlet/default",
selectors = "imgnode",
extensions = {"png","jpg","jpeg","gif"},
methods = "GET"
)
public class SimpleImageServlet extends AbstractImageServlet {
Where img.png.java had the following line:
Image image = new Image(c.resource, "image");
I changed it to:
Image image = new Image(c.resource);
This relies on SCR annotations to generate the OSGi configuration so that this servlet will handle image requests having the imgnode selector. Instead of looking for a child image node it just expects the current resource to be an image.
Second, I added a component to the body.jsp overlay of the page component, like so.
<cq:include path="logo" resourceType="/apps/my-site/components/logo" />
This maps the logo path to a component for rendering.
Third, within the logo.jsp on the component I set the selector to imgnode rather than img.
Image img = new Image(resourcePage, "logo");
img.setSelector("imgnode");
I believe this step would be similar if the adaptiveimage were overlayed. You just need to render out URLs that include the imgnode selector.
Fourth, I setup the logo image dialog tab in page properties to use the expected requestSuffix and set the other properties to point to the logo sub-node.
Examples:
requestSuffix = "/logo.imgnode.png"
fileReferenceParameter = "./logo/fileReference"
Fifth, I made sure that the image dialog tab for the /apps/my-site/components/logo component pointed to itself.
Examples:
requestSuffix = ".imgnode.png"
fileReferenceParameter = "./fileReference"
Now whether it is in page properties, component editing, or final rendering, the image is handled appropriately.
this is a bit of a nuisance with using the image widget controls--only the image component nicely handles the data, and the servlet that handles ".img" is tied to the image component resourceType.
the easiest thing is to just use the value of the fileReference property instead of referencing the image as part of the page. since you're using assets from DAM, this is a reasonable approach.
this doesn't address the issue with a user uploading an image directly. i wanted to suggest having a hidden field like "./logo/sling:resourceType", but testing that locally resulted in an error when trying to save the dialog.
another approach is the following:
<sling:include resourceType="foundation/components/adaptiveimage" resource="${resource.path}/logo" />
(assuming resource is jcr:content). this is effectively the same as adding a sling:resourceType, but there are at least 2 downsides:
the image becomes authorable at that point as opposed to in the dialog
this method only works for rendering a normal tag. it won't work for any sort of background image
I want execute some logic after the moment when widget is attached and all images inside this widget are loaded. This widget show a block of html prepared in CMS (so the number of images is dynamic).
What have I tried:
override Widget.onAttach() or Widget.onLoad(). Unfortunately both of them are executed before the moment when all images are loaded.
I found gwt-image-loader library which can add a callback per image. I wan't use it due to dynamic nature of the content.
In JavaScript there is this option which works great:
$('selector').waitForImages(function() {
// do some logic
});
Maybe I missed some GWT way to do the same thing?
You can try GWT's Image.addLoadHandler()
onLoad and onAttach methods are there to inform you that the <img> tag is attached to your document and that is it. This helps in setting image attributes such as height, width, position and so on. What you are asking is, after the image is attached to document you want an handler after the image is rendered. This is not possible with the current version of GWT as per my experience. Further rendering of image depends on the network you are in, the server you are connected and so on. So instead of wanting for a render callback, try to do the work in onLoad or onAttach methods or add a loadHandler for the same
I want to display an "img" element as a child of a panel. Should we be using the Image widget for this? I'm doing the following:
Image img = new Image();
img.getElement().getStyle().setWidth(80, Style.Unit.PX);
img.getElement().getStyle().setHeight(80, Style.Unit.PX);
// add it to a panel, which eventually gets added to the root panel.
somePanel.add(img);
// set the url
img.setUrl("stuff/test.png");
This works fine on FF. When I run the same code in mobile safari, the images never load. I've added a LoadHandler to the Image instance. I can see that on FF, the event callbacks are triggered. But on mobile safari, they're never triggered.
I recall that an Image must be added to the RootPanel in order for it to ever load, but I am indeed doing that. What else could be causing this? I'm sure the png resource is located correctly.
Thanks
Rule of thumb: always use absolute URLs, possibly using GWT.getModuleBaseURL(), GWT.getHostPageBaseURL() or GWT.getModuleBaseForStaticFiles() as a prefix:
img.setUrl(GWT.getHostPageBaseURL() + "stuff/test.png");
This is because GWT code runs in an iframe and is loaded from within a subfolder, and browsers differ in behavior on whether to use the host page or the iframe URL to resolve relative URLs.
I have a form with an Image widget and a FileUpload widget.
I can use file upolad to change images.
I'd like to visualise a changed image right after a new image is submited to a servlet. But how can I force an Image widget to grab a new image from server ? (image's url doesn't change, content does) .
If you can't/don't want to change the URL on the server, you can alternatively add a query parameter like:
version++;
image.setUrl(url + "?v" + version);
The query parameter will be ignored on the server (except if you want to use it somehow), but it forces a reload, because the browser doesn't know, if the image might be generated dynamically.
Or better: just set the URL to "" then back to the original URL. Tested in Chrome.
String url = image.getUrl();
image.setUrl("");
image.setUrl(url);
I have an Ext Js panel that I am adding to my main TabPanel. The panel I am adding contains a FormPanel as one of it's items and inside the FormPanel I have a Name field. What I want to do is change the name of the Tab based on the name in the form field.
The problem is that if I call the FormPanel's getForm().getValues() inside of the panel's initComponent, I get the following javascript error:
Uncaught TypeError: Cannot read property 'dom' of undefined
If I do this outside of initComponent (e.g. on a button press) everything works fine. After doing some testing, I think the issue is that the FormPanel isn't actually rendered yet (and thus the dom doesn't exist), getValues() fails. However, I can't seem to figure out a way to get my FormPanel's values from the Panel on load.
I tried to listen for events. I tried:
this.detailForm.on('afterrender', function () { alert('test'); });
but doing this showed that AfterRender is called prior to the form actually being rendered (it's not visible on the screen). Changing the alert to my custom function handler produces the previous dom exception. I attempted to use the activate and enable events instead of afterrender, but even though the API says that FormPanel fires those events, the alert('test') never gets called.
I can't seem to find any way for my panel to get the inner FormPanel's values upon loading my panel. Does anyone have any ideas?
Using getFieldValues() in place of getValues() will collect values by calling each field instance's getValue() method instead of by reading from the DOM. This should allow you to get your values regardless of the form's rendered state.
I've got the same problems on one of my projects, I managed to fix it using the afterlayout event.
I'd give setting .deferredRender:false a try.
Ext.TabPanel.deferredRender
Probably best to roll out of your afterlayout changes, then test with just a straight deferredRender:false config item.
I believe the problem is caused because the inactive tabs are not rendered until they become active. In your scenario, you cannot get the values, because they don't exist until the tab is activated/shown.
Setting deferredRender:false will render the items within all tabs. There could be a performance hit by setting deferredRender:false, so testing you must do.
Hope this helps.