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我们已经从 primefaces 实现了 datascroller 并使用lazy=true 对其进行了扩展，这对于第一次延迟加载来说效果很好。但是当我向下滚动时，前端不会触发任何事件。后端按预期工作。

我通过更改块大小对其进行测试，并更好地了解后端代码中发生的情况。当您到达页面末尾时，我们会覆盖 primefaces 调用的加载函数。我通过滚动将代码更改为不延迟加载，因此我实现了一个按钮以在您单击按钮时加载下一个块。但是按钮单击一次后消失。

Xhtml:

                        <p:dataScroller value="#{stakeholderOverviewController.model}" var="stakeholder" chunkSize="50" lazy="true" rowIndexVar="test">

                            <f:facet name="header">
                                Scroll Down to Load More Cars 
                            </f:facet>
                            <f:facet name="loader">
                                <p:commandButton type="button" value="More" icon="pi pi-chevron-circle-down"/>
                            </f:facet>
                            <h:panelGrid columns="2" style="width:100%" columnClasses="logo,detail">
                                <p:outputPanel>
                                    <h:panelGrid columns="2" cellpadding="5">
                                        <h:outputText value="Id:" />
                                        <h:outputText value="#{stakeholder.lastname}" style="font-weight: bold"/>

                                        <h:outputText value="Year:" />
                                        <h:outputText value="#{stakeholder.firstname}" style="font-weight: bold"/>

                                    </h:panelGrid>
                                </p:outputPanel>
                            </h:panelGrid>
                            <ui:include  rendered="#{empty stakeholder}" src="/WEB-INF/compositions/stakeholderEmptyModel.xhtml" />
                        </p:dataScroller>

有Controller的后端代码：

    public StakeholderOverviewController() {
        model = new LazyDataModel<StakeholderSearchWrapper>() {

            @Override
            public List<StakeholderSearchWrapper> load(int first, int pageSize, String sortField, SortOrder sortOrder,
                    Map filters) {

                List<StakeholderSearchWrapper> execQuery = execQuery(first, pageSize);
                return execQuery;
            }
        };
        model.setRowCount(0);
    }

....

protected synchronized List<StakeholderSearchWrapper> execQuery(int first, int pageSize) {
        if (tmpfirst != first || tmppageSize != pageSize || reExecQuery) {
            reExecQuery = false;
            tmpfirst = first;
            tmppageSize = pageSize;

            tmpModel = new LinkedList<>();

            // Query for stakeholder
            queryresponse = stakeholderService.findByLastnameOrFirstmanOwnerOrShare(getSearchText(), getClientId(),
                    first, pageSize, selectedFacets, nameSort[getSort()]);

            setFacets(queryresponse.getFacetFields());
            Set<String> stakeholderIds = new HashSet<String>();

            // convert for view
            for (SolrDocument details : queryresponse.getResults()) {
                StakeholderSearchWrapper stakeholderSearchWrapper = new StakeholderSearchWrapper(details);

                tmpModel.add(stakeholderSearchWrapper);
                stakeholderIds.add(stakeholderSearchWrapper.getId());
            }

            historyCount = stakeholderService.countHistoryEntryByStakeholders(stakeholderIds);
            notesCount = stakeholderService.countNoteEntriesByStakeholders(stakeholderIds);
            assignedProjects = projectService.findByStakeholderIds(stakeholderIds);

            for(StakeholderSearchWrapper dao : tmpModel) {
                dao.setHistoryCount(getHistoryCount(dao.getId()));
                dao.setNoteCount(getNoteEntriesCount(dao.getId()));
                dao.setProjects(getAssignedProjects(dao.getId()));
            }


            SolrDocumentList result = queryresponse.getResults();
            int numFound = (int) result.getNumFound();

            return tmpModel;
        } else {
            return tmpModel;
        }
    }

我想要的是延迟加载不会只触发一次。它应该根据需要经常触发。我不知道我必须在哪里设置一些变量才能做到这一点。在调试当前代码时，仅在第一次运行页面刷新时才请求加载函数，然后调用一个延迟加载，但随后什么也没有发生。

4

1 回答 1

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我想我意识到了诀窍。检查线路：

model.setRowCount(0);

相反，使用您要显示的最大数据量正确设置模型行数：

int totalNumberOfRegisters = this.count(/* relevant paramenters*/);
model.setRowCount(totalNumberOfRegisters);
于 2020-04-23T18:28:19.727 回答