Question

有人可以解释一件事吗？是否可以将Vaadin TreeTable与LazyQueryContainer一起使用？我已经尝试了但它不起作用。实际上，没有任何延迟加载。调用org.vaadin.addons.lazyquerycontainer.Query的方法 loadItems ，直到加载所有数据。对于instanse，如果容器的批量大小= 100并且我有500行，则此方法将被调用5次。这是我的代码：

public class LazyHierarchicalQueryContainer extends LazyQueryContainer implements Container.Hierarchical {

    private String parentProperty = "parent";

    public LazyHierarchicalQueryContainer(QueryFactory queryFactory, Object idPropertyId, int batchSize,
        boolean compositeItems) {
        super(queryFactory, idPropertyId, batchSize, compositeItems);
    }

    public LazyHierarchicalQueryContainer(QueryDefinition queryDefinition, QueryFactory queryFactory) {
        super(queryDefinition, queryFactory);
    }

    public LazyHierarchicalQueryContainer(QueryView queryView) {
        super(queryView);
    }

    public String getParentProperty() {
        return parentProperty;
    }

    public void setParentProperty(String parentProperty) {
        this.parentProperty = parentProperty;
    }

    @Override
    public Collection<?> getChildren(Object itemId) {
        return Collections.emptyList();
    }

    @Override
    public Object getParent(Object itemId) {
        return null;
    }

    @Override
    public Collection<?> rootItemIds() {
        ArrayList arrayList = new ArrayList();
        for (Object workItem : getItemIds()) {
            if (isRoot(workItem)) {
                arrayList.add(workItem);
            }
        }
        return arrayList;
    }

    @Override
    public boolean setParent(Object itemId, Object newParentId) throws UnsupportedOperationException {
        if (getItem(newParentId) != null) {
            getItem(itemId).getItemProperty(getParentProperty()).setValue(newParentId);
        } else {
            getItem(itemId).getItemProperty(getParentProperty()).setValue(null);
        }
        return true;
    }

    @Override
    public boolean areChildrenAllowed(Object itemId) {
        return true;
    }

    @Override
    public boolean setChildrenAllowed(Object itemId, boolean areChildrenAllowed) throws UnsupportedOperationException {
        return false;
    }

    @Override
    public boolean isRoot(Object itemId) {
        return getItem(itemId).getItemProperty(parentProperty).getValue() == null;
    }

    @Override
    public boolean hasChildren(Object itemId) {
        return false;
    }
}

提前致谢。

Answer 1

看来你的rootItemIds（）实现加载所有项来过滤掉根项。这可能会导致整个容器在第一时间被读取。

使用LazyQueryContainer的Vaadin TreeTable

1 个答案: