PF的graphicImage无法渲染 [英] PF's graphicImage doesn't render

问题描述

我正在使用JSF/PF，但我无法使graphicImage正常工作.回顾论坛上发布的大量主题，此PF的graphicImage似乎非常棘手.我显然做错了事，但是，只要我复制对其他人有用的代码(请参阅帖子)，它一定是组件环境中的东西.我希望在这里找到一个解决方案，我陷入了数周的困境.谢谢

I'am using JSF/PF anf I can't make a graphicImage work. Reviewing the tons of topics published on forums, this PF's graphicImage seems to be so tricky. I am obviously doing somethig wrong, but, as long as I am replicating code that worked for others (see post), it must be something in the environment of the component. I hope to find a solution here, i'm stuck for weeks. Thanks

这是我在PF论坛中的原始问题:

Here is my original question in PF forum:

我在渲染图像时遇到问题.我已经按照说明的代码进行操作，并且可以正确检索图像的ID以在单独的方法中显示:

I encounter a problem rendering the image. I have followed the code explained and I correctly retrieve the id for image to display in a separate method:

public StreamedContent getStreamedImage() {

        StreamedContent streamedImage = null;
                UIViewRoot uiRoot = FacesContext.getCurrentInstance().getViewRoot();

        System.out.println(uiRoot.getClientId());

        UIComponent component = FacesContext.getCurrentInstance().getViewRoot().findComponent("itemDataForm:imagesTbl:itemImgComp");
        Map attributes = component.getAttributes();
        Integer image_id = (Integer)attributes.get("item_img_id");

        if(image_id != null && editionItem != null && editionItem.getImages() != null){
            for(ItemImageView img : editionItem.getImages()){
                if(image_id.intValue() == img.getId()){
                    streamedImage = new DefaultStreamedContent(new ByteArrayInputStream(img.getImage()), "image/jpeg");
                }
            }
        }else{
            streamedImage = new DefaultStreamedContent(new ByteArrayInputStream(editionItem.getImages().get(0).getImage()), "image/jpeg");
        }
.......

我无法设法检索(始终为null)，所以我尝试使用attribute，它可以工作.因此，将加载DefaultStreamContent，因为图像根本不会呈现.我的xhtml代码:

I could't manage to retrieve the (always null) so I tried with attribute and it works. So, the DefaultStreamContent is loaded, by the image doesn't render at all. My code for xhtml:

<p:dataTable id="imagesTbl" var="itemImg" value="#{itemEditionBean.editionItem.images}">
                                        <p:column>
                                            <h:panelGrid columns="1">
                                                <h:outputText value="#{itemImg.id}"/>
                                                <p:graphicImage id="itemImgComp" value="#{itemEditionBean.streamedImage}">
                                                    <f:attribute name="item_img_id" value="#{itemImg.id}"/>
                                                </p:graphicImage>
                                            </h:panelGrid>
                                        </p:column>
                                    </p:dataTable>

与上述主题中的代码完全相同. PS:我在选项卡中包含了mt dataTable.也许依赖于封闭的组件，形式或什么?

Exactly the same that the code working in this topic above. PS: I have mt dataTable enclosed within a tab. Maybe a dependency on the enclosing component, or form, or what?

可以从下面的链接中查看来自其他相关主题的大量代码:

There is a huge amount of code from other related topics that can be viewed in the link below:

http://forum.primefaces.org/viewtopic.php?f = 3& t = 4163& p = 39751

推荐答案

基于我在显示动态图像的问题，但发现存在一个问题，它们与ConversationScoped bean结合使用了.我将支持bean切换到Session作用域，现在可以正常工作了.

Based on another page I found on building dynamic images, <f:param .../> should be used to supply a parameter to the getStreamedImage() method rather than <f:attribute .../>. Are you using a ConversationScoped backing bean? I was having the same problem displaying dynamic images, but found that there is a problem using them with ConversationScoped beans. I switched my backing bean to Session scope and now it works fine.

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