javafx 列表视图和树视图控件未正确重绘 [英] javafx listview and treeview controls are not repainted correctly

问题描述

我正在尝试使用 javafx 将元素放在列表视图和树视图上，但两个控件都不会刷新它们的内容.我使用 obvservable 列表来控制项目，每次我删除一个项目时，列表视图或树视图都会将它从数据源中删除.但视图没有更新.我仍然看到所有的项目.唯一的区别是，被移除的项目不能再被选中.例如链接 2 显示折叠的项目列表.图 1 显示了折叠之前的项目.项目已折叠，但旧条目仍然可见.有没有人知道这个问题的解决方案.谢谢大家帮我

i am trying to put elements on a listview and treeview with javafx, but both controls wont refresh theyre content. i am using an obvservable list to control the items and every time i delete one item, the listview or treeview removes it from the datasource. but the view is not updating. i am still seeing all the items. the only difference is, the removed item can not be selected any more. for example link 2 shows the collaped item list. image 1 shows the items before they are collaped. the items are collapsed but the old entry is still visible. does anybody know a solution for this problem. thank you all for helping me

链接 1:treeview 未折叠链接 2:treeview 已折叠但未更新旧视图

这是我用来显示列表视图的自定义单元工厂:

this is the custom cell factory i use to display a listview:

public ListCell<T> call(final ListView<T> param) {
        ListCell<T> cell = new ListCell<T>(){
            @Override
            protected void updateItem(final T persistentObject, final boolean empty) {
                super.updateItem(persistentObject, empty);
                if(persistentObject instanceof POProcessStep){
                    POProcessStep poProcessStep = (POProcessStep) persistentObject;
                    if (persistentObject != null) {
                        super.setText(poProcessStep.getId() + " - " + poProcessStep.getTitle());
                    }
                }else if(persistentObject instanceof POProcess){
                    POProcess poProcess = (POProcess) persistentObject; 
                    if (persistentObject != null) {
                        super.setText(poProcess.getId() + " - " + poProcess.getTitle());
                    }
                }else if(persistentObject instanceof POCategory){
                    POCategory poCategory = (POCategory) persistentObject;
                    if(persistentObject != null){
                        super.setText(poCategory.getId() + " - " + poCategory.getTitle());
                    }
                }else if(persistentObject instanceof String){
                    if(persistentObject != null){
                        super.setText(String.valueOf(persistentObject));
                    }
                }
                super.setGraphic(null);
            }
        };
        return cell;
    }

推荐答案

你的cell factory的updateItem(...)需要处理cell为空的情况.当一个项目被移除(或者因为 TreeView 中的一个节点被折叠而变成空)并且之前显示一个项目的单元格被重新用作空单元格时，这将是完全正确的场景:

Your cell factory's updateItem(...) needs to handle the case where the cell is empty. This will be exactly the scenario when an item is removed (or becomes empty because a node in the TreeView was collapsed) and the cell that previously showed an item is reused as an empty cell:

public ListCell<T> call(final ListView<T> param) {
    ListCell<T> cell = new ListCell<T>(){
        @Override
        protected void updateItem(final T persistentObject, final boolean empty) {
            super.updateItem(persistentObject, empty);
            if (empty) {
                setText(null);
                setGraphic(null);
            } else {
                // ... rest of your code.
            }
       }
    }
    return cell ;
}

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