在更新TreeTableView時，似乎是隨機的NullPointerException

Question

我只是將過濾添加到TreeTableView中，並且開始出現似乎是隨機的錯誤（可能不是隨機的）。 我可以通過向過濾器textField發送垃圾郵件來重現它，以更新TreeTableView直到出現阻塞。 我得到以下堆棧跟蹤，TreeTableView不再更新，但程序不會崩潰。 與我的代碼相關的堆棧跟蹤的唯一部分指向cellFactory，在其中我重寫CheckBoxTreeTableCell的updateItem以便為頂層行實現樣式：

colActShop.setCellFactory(column ->{
        return new CheckBoxTreeTableCell<Product, Boolean>(){
            @Override
            public void updateItem(Boolean item, boolean empty) {
                super.updateItem(item, empty);
                boolean isTopLevel = getTreeTableView().getRoot().getChildren()
                                   .contains(getTreeTableRow().getTreeItem());
                if(item == null || empty){
                    setText(null);
                    setGraphic(null);
                    //It crashes on the following line according to the stack trace
                    getTreeTableRow().getStyleClass().remove("topLevelRow");
                }else{
                    if(isTopLevel){
                        getTreeTableRow().getStyleClass().add("topLevelRow");
                    }else{
                        getTreeTableRow().getStyleClass().remove("topLevelRow");
                    }

                    setEditable(!isTopLevel);   
                }
            }
        };
    });

如果我刪除了getTreeTableRow().getStyleClass()...行，則似乎正在刪除該錯誤，但隨后我失去了正在尋找的樣式行為。 我也拼命嘗試在某些地方放置一些Platform.runlater ，但沒有成功。 由於過濾和TreeTableView更新變得越來越大，我現在無法提供一個最小的可執行示例。 當我在過濾器textField中輸入文本時，將調用以下函數來更新TreeTableView的根：

     /**
  * A method to update a TreeTableView every time backing data changes in the model,
  * without resetting the table by only adding and removing data when required.
  * Also applies filters
  * @param root : the root TreeItem of the table to update
  * @param inventory : the inventory backing this table
  * @param shop : the shop to calculate the price of products
  * @param filter : comma separated string filter
  * @param catFilter : category filter list
  */
private void updateTreeItemRoot(TreeItem<Product> root, Inventory inventory, Shop shop, String filter, ArrayList<String> catFilter){
    inventory.clean();
    shop.clean();
    inventory.calculateAverageData();
    //retrieve the product list of category items of the previous TreeTableView structure before updating
    ArrayList<Product> oldProdCategoryList= new ArrayList<Product>();
    ArrayList<TreeItem<Product>> oldTreeItemCategoryList= new ArrayList<>(root.getChildren());
    for(TreeItem<Product> treeItem : oldTreeItemCategoryList){
        oldProdCategoryList.add(treeItem.getValue());
    }
    for(Entry<String, ArrayList<Product>> entry : inventory.getData().entrySet()){
        Product product = inventory.getAverageData(entry.getKey());
        //Filtering the TreeTableView 
        boolean filterOK = false;
        if(catFilter!=null){
            if(catFilter.contains("All")||catFilter.contains("All seeds")){
                filterOK = true;
            }else{
                //else look for any matching categories
                for(String str:catFilter){
                    if(product.getCategories().stream().anyMatch(s -> s.equals(str))){
                        filterOK = true;
                        break;
                    }
                }
            }
            //turn filterOk to false if we want only mature and product is not
            if(catFilter.contains("Only mature")&&product.getMaturity()!=100) {
                filterOK = false;
            }
            //turn filterOK to false if we want only seeds and the product is not a seed
            if(catFilter.contains("Only seeds")){
                if(!(product.getCategories().stream().anyMatch(s -> s.equals("Seed")))){
                    filterOK = false;
                }
            }
        }else{
            filterOK = true;
        }
        String[] filterList = filter.split(",");
        if(filter.length()>0&&!Arrays.stream(filterList).anyMatch(s->product.getName().matches( "(?i:.*"+s+".*)"))){
            filterOK = false;
        }
        if(filterOK){
            product.updatePrice(shop);
            TreeItem<Product> averageProdDataItem; ;
            //if this product category is not yet present in the table add it.
            if(!oldProdCategoryList.contains(product)){
                averageProdDataItem = new TreeItem<Product>(product);
                averageProdDataItem.setExpanded(true);
                root.getChildren().add(averageProdDataItem);
            }else{
                //else if this product category is already in the table, retrieve the reference and remove it from the 
                //  "old" Lists to see if something needs to be removed from the table in the end
                averageProdDataItem = oldTreeItemCategoryList.get(oldProdCategoryList.indexOf(product));
                oldTreeItemCategoryList.remove(oldProdCategoryList.indexOf(product));
                oldProdCategoryList.remove(product);
            }
            //retrieve the product list for this category category of the previous TreeTableView structure before updating
            ArrayList<Product> oldProdList= new ArrayList<Product>();
            ArrayList<TreeItem<Product>> oldTreeItemList= new ArrayList<>(averageProdDataItem.getChildren());
            for(TreeItem<Product> treeItem : oldTreeItemList){
                oldProdList.add(treeItem.getValue());
            }
            for(Product prod : entry.getValue()){
                prod.updatePrice(shop);
                TreeItem<Product> treeItem;
                //if the table does not contain this prod, add it
                if(!oldProdList.contains(prod)){
                    treeItem = new TreeItem<Product>(prod);
                    averageProdDataItem.getChildren().add(treeItem);
                }else{

                    oldTreeItemList.remove(oldProdList.indexOf(prod));
                    oldProdList.remove(prod);
                }
            }
            averageProdDataItem.getChildren().removeAll(oldTreeItemList); //clean up empty products
        }// if filterOK
    }//for
    root.getChildren().removeAll(oldTreeItemCategoryList);// clean up empty categories
}

這似乎是相同的這個問題已經打開的3倍和關閉沒有任何評論。

堆棧跟蹤：

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
    at com.sun.javafx.scene.control.skin.CellSkinBase.access$200(CellSkinBase.java:54)
    at com.sun.javafx.scene.control.skin.CellSkinBase$StyleableProperties$1.getStyleableProperty(CellSkinBase.java:149)
    at com.sun.javafx.scene.control.skin.CellSkinBase$StyleableProperties$1.getStyleableProperty(CellSkinBase.java:138)
    at javafx.scene.CssStyleHelper.resetToInitialValues(CssStyleHelper.java:447)
    at javafx.scene.CssStyleHelper.createStyleHelper(CssStyleHelper.java:180)
    at javafx.scene.Node.reapplyCss(Node.java:8983)
    at javafx.scene.Node.reapplyCss(Node.java:9012)
    at javafx.scene.Node.impl_reapplyCSS(Node.java:8946)
    at javafx.scene.Node$3.onChanged(Node.java:1023)
    at com.sun.javafx.collections.TrackableObservableList.lambda$new$29(TrackableObservableList.java:45)
    at com.sun.javafx.collections.ListListenerHelper$SingleChange.fireValueChangedEvent(ListListenerHelper.java:164)
    at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
    at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
    at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
    at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
    at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
    at javafx.collections.ModifiableObservableListBase.remove(ModifiableObservableListBase.java:183)
    at javafx.collections.ModifiableObservableListBase.remove(ModifiableObservableListBase.java:171)
    at homier.farmGame.controller.Engine$2.updateItem(Engine.java:768)
    at homier.farmGame.controller.Engine$2.updateItem(Engine.java:1)
    at javafx.scene.control.TreeTableCell.updateItem(TreeTableCell.java:630)
    at javafx.scene.control.TreeTableCell.indexChanged(TreeTableCell.java:457)
    at javafx.scene.control.IndexedCell.updateIndex(IndexedCell.java:116)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.recreateCells(TableRowSkinBase.java:671)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.updateCells(TableRowSkinBase.java:499)
    at com.sun.javafx.scene.control.skin.TreeTableRowSkin.updateCells(TreeTableRowSkin.java:220)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.checkState(TableRowSkinBase.java:631)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.computePrefHeight(TableRowSkinBase.java:571)
    at javafx.scene.control.Control.computePrefHeight(Control.java:547)
    at javafx.scene.Parent.prefHeight(Parent.java:935)
    at javafx.scene.layout.Region.prefHeight(Region.java:1435)
    at com.sun.javafx.scene.control.skin.VirtualFlow.resizeCellSize(VirtualFlow.java:1947)
    at com.sun.javafx.scene.control.skin.VirtualFlow.addLeadingCells(VirtualFlow.java:1247)
    at com.sun.javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1194)
    at javafx.scene.Parent.layout(Parent.java:1087)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Scene.doLayoutPass(Scene.java:552)
    at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2397)
    at com.sun.javafx.tk.Toolkit.lambda$runPulse$29(Toolkit.java:398)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:397)
    at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:424)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:518)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:498)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:491)
    at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$403(QuantumToolkit.java:319)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Unknown Source)
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
    at com.sun.javafx.scene.control.skin.CellSkinBase.access$200(CellSkinBase.java:54)
    at com.sun.javafx.scene.control.skin.CellSkinBase$StyleableProperties$1.getStyleableProperty(CellSkinBase.java:149)
    at com.sun.javafx.scene.control.skin.CellSkinBase$StyleableProperties$1.getStyleableProperty(CellSkinBase.java:138)
    at javafx.scene.CssStyleHelper.resetToInitialValues(CssStyleHelper.java:447)
    at javafx.scene.CssStyleHelper.createStyleHelper(CssStyleHelper.java:180)
    at javafx.scene.Node.reapplyCss(Node.java:8983)
    at javafx.scene.Node.impl_reapplyCSS(Node.java:8946)
    at javafx.scene.control.Control$1.invalidated(Control.java:300)
    at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:111)
    at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
    at javafx.css.StyleableObjectProperty.set(StyleableObjectProperty.java:82)
    at javafx.scene.control.Control$1.set(Control.java:237)
    at javafx.scene.control.Control$1.set(Control.java:220)
    at javafx.scene.control.Control.setSkin(Control.java:217)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.recreateCells(TableRowSkinBase.java:673)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.updateCells(TableRowSkinBase.java:499)
    at com.sun.javafx.scene.control.skin.TreeTableRowSkin.updateCells(TreeTableRowSkin.java:220)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.checkState(TableRowSkinBase.java:631)
    at com.sun.javafx.scene.control.skin.TableRowSkinBase.computePrefHeight(TableRowSkinBase.java:571)
    at javafx.scene.control.Control.computePrefHeight(Control.java:547)
    at javafx.scene.Parent.prefHeight(Parent.java:935)
    at javafx.scene.layout.Region.prefHeight(Region.java:1435)
    at com.sun.javafx.scene.control.skin.VirtualFlow.resizeCellSize(VirtualFlow.java:1947)
    at com.sun.javafx.scene.control.skin.VirtualFlow.addLeadingCells(VirtualFlow.java:1247)
    at com.sun.javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1194)
    at javafx.scene.Parent.layout(Parent.java:1087)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Parent.layout(Parent.java:1093)
    at javafx.scene.Scene.doLayoutPass(Scene.java:552)
    at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2397)
    at com.sun.javafx.tk.Toolkit.lambda$runPulse$29(Toolkit.java:398)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:397)
    at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:424)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:518)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:498)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:491)
    at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$403(QuantumToolkit.java:319)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Unknown Source)

有人有指導我調試的想法嗎？ 我是否需要放棄某些行的樣式？

編輯1經過進一步測試后，它比我想象的要少隨機性。 我在過濾器字段中輸入一個字母，然后在卡紙前將其刪除34次。 如果我使用一系列字母（而不是每次都使用相同的字母），它似乎比34（例如29或31）早於卡紙。因此，我認為每次迭代都不會清除某些內容，但我不知道該怎么做。

Answer 1

我仍然不知道該錯誤的原因。 我想我找到了一種方法，通過在TreeTableView上使用setRowFactory而不是在setCellFactory上使用setCellFactory和getTreeTableRow()來設置特殊行的樣式。 由於Row是同一個對象，所以看起來很奇怪，我只是以不同的方式訪問它，但是到目前為止，我還沒有使用這種方式的錯誤。

    tableShop.setRowFactory(table-> {
        return new TreeTableRow<Product>(){
            @Override
            public void updateItem(Product pers, boolean empty) {
                super.updateItem(pers, empty);      
                boolean isTopLevel = table.getRoot().getChildren().contains(treeItemProperty().get());
                if(pers==null||empty) {
                    setText(null);
                    setGraphic(null);
                    getStyleClass().remove("topLevelRow");
                }else {
                    if(isTopLevel) {
                        if(!getStyleClass().contains("topLevelRow")) {
                            getStyleClass().add("topLevelRow");
                        }
                    }else {
                        getStyleClass().remove("topLevelRow");
                    }
                }
            }
        };
    });