在带有 FXML 的 JavaFX 中使用 TreeTableView 的应用程序不会启动
Application with TreeTableView in JavaFX with FXML wont start
我正在尝试在 JavaFX 中构建一个简单的应用程序，它使用 TreeTableView 来显示项目，并使用几个按钮和文本字段来输入和删除这些列表中的内容。但我无法启动应用程序。我得到一个 Exception in Application start method 并且我不知道发生了什么。也许有人可以帮助我？
这是我的主class:
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
public static void main (String[] args){
launch(args);
}
@Override
public void start (Stage primaryStage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Name");
primaryStage.setScene(new Scene(root, 520, 620));
primaryStage.show();
}
}
这是我的控制器：
package sample;
import com.sun.source.tree.Tree;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.value.ObservableValue;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeTableColumn;
import javafx.scene.control.TreeTableView;
import javafx.util.Callback;
import java.net.URL;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
private TreeTableView<String> tableView;
@FXML
private TreeTableColumn<String, String> col1;
// TreeItems and Parent 1
TreeItem<String> item1_l1 = new TreeItem<>("Name_Item1_Level1");
TreeItem<String> item2_l1 = new TreeItem<>("Name_Item2_Level1");
TreeItem<String> item3_l1 = new TreeItem<>("Name_Item3_Level1");
TreeItem<String> parent1 = new TreeItem<>("Parent1");
TreeItem<String> item1_l2 = new TreeItem<>("Name_Item1_Level2");
TreeItem<String> item2_l2 = new TreeItem<>("Name_Item2_Level2");
TreeItem<String> item3_l2 = new TreeItem<>("Name_Item3_Level2");
TreeItem<String> parent2 = new TreeItem<>("parent2");
// Setting up the Root for TreeItem
TreeItem<String> root = new TreeItem<>("Root");
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
parent1.getChildren().setAll(item1_l1, item2_l1, item3_l1);
parent2.getChildren().setAll(item1_l2, item2_l2, item3_l2);
root.getChildren().setAll(parent1, parent2);
tableView.setRoot(root);
col1.setCellValueFactory(
(TreeTableColumn.CellDataFeatures<String, String>param) -> new SimpleStringProperty(param.getValue().getValue()));
}
}
这是我的 sample.fxml 文件：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="620.0" prefWidth="520.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<center>
<VBox BorderPane.alignment="CENTER">
<children>
<MenuBar>
<menus>
<Menu mnemonicParsing="false" text="File">
<items>
<MenuItem mnemonicParsing="false" text="Close" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Edit">
<items>
<MenuItem mnemonicParsing="false" text="Delete" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Help">
<items>
<MenuItem mnemonicParsing="false" text="About" />
</items>
</Menu>
</menus>
</MenuBar>
<TreeTableView prefHeight="556.0" prefWidth="520.0">
<columns>
<TreeTableColumn prefWidth="270.0" text="C1" />
</columns>
</TreeTableView>
<HBox spacing="20.0" VBox.vgrow="ALWAYS">
<children>
<TextField />
<TextField />
<Region prefHeight="27.0" prefWidth="47.0" HBox.hgrow="ALWAYS" />
<Button mnemonicParsing="false" text="Add" />
</children>
<VBox.margin>
<Insets bottom="8.0" left="8.0" right="8.0" top="8.0" />
</VBox.margin>
</HBox>
</children>
</VBox>
</center>
</BorderPane>
最后但同样重要的是，这是我在尝试启动应用程序时遇到的错误：
Exception in Application start method
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:464)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:363)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1051)
Caused by: java.lang.RuntimeException: Exception in Application start method
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication(LauncherImpl.java:195)
at java.base/java.lang.Thread.run(Thread.java:830)
Caused by: javafx.fxml.LoadException:
/Users/c-mon/IdeaProjects/Guccifer%20copy/out/production/Guccifer/sample/sample.fxml
at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2625)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2603)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3237)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3194)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3163)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3136)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3113)
at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3106)
at sample.Main.start(Main.java:17)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1(LauncherImpl.java:846)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait(PlatformImpl.java:455)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater(PlatformImpl.java:428)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater(PlatformImpl.java:427)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
Caused by: java.lang.NullPointerException
at sample.Controller.initialize(Controller.java:43)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573)
... 14 more
Exception running application sample.Main
您的 tableView 和 col1 未绑定到布局标签，因此 NPE 发生在 tableView.setRoot() 中。
您应该对这两个元素执行此操作：<TreeTableView prefHeight="556.0" prefWidth="520.0" fx:id="tableView"> 然后从 FXML 创建的 TreeTableView 将写入控制器的 tableView 字段。
我正在尝试在 JavaFX 中构建一个简单的应用程序，它使用 TreeTableView 来显示项目，并使用几个按钮和文本字段来输入和删除这些列表中的内容。但我无法启动应用程序。我得到一个 Exception in Application start method 并且我不知道发生了什么。也许有人可以帮助我？
这是我的主class:
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
public static void main (String[] args){
launch(args);
}
@Override
public void start (Stage primaryStage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Name");
primaryStage.setScene(new Scene(root, 520, 620));
primaryStage.show();
}
}
这是我的控制器：
package sample;
import com.sun.source.tree.Tree;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.value.ObservableValue;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeTableColumn;
import javafx.scene.control.TreeTableView;
import javafx.util.Callback;
import java.net.URL;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
private TreeTableView<String> tableView;
@FXML
private TreeTableColumn<String, String> col1;
// TreeItems and Parent 1
TreeItem<String> item1_l1 = new TreeItem<>("Name_Item1_Level1");
TreeItem<String> item2_l1 = new TreeItem<>("Name_Item2_Level1");
TreeItem<String> item3_l1 = new TreeItem<>("Name_Item3_Level1");
TreeItem<String> parent1 = new TreeItem<>("Parent1");
TreeItem<String> item1_l2 = new TreeItem<>("Name_Item1_Level2");
TreeItem<String> item2_l2 = new TreeItem<>("Name_Item2_Level2");
TreeItem<String> item3_l2 = new TreeItem<>("Name_Item3_Level2");
TreeItem<String> parent2 = new TreeItem<>("parent2");
// Setting up the Root for TreeItem
TreeItem<String> root = new TreeItem<>("Root");
@Override
public void initialize(URL url, ResourceBundle resourceBundle) {
parent1.getChildren().setAll(item1_l1, item2_l1, item3_l1);
parent2.getChildren().setAll(item1_l2, item2_l2, item3_l2);
root.getChildren().setAll(parent1, parent2);
tableView.setRoot(root);
col1.setCellValueFactory(
(TreeTableColumn.CellDataFeatures<String, String>param) -> new SimpleStringProperty(param.getValue().getValue()));
}
}
这是我的 sample.fxml 文件：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<BorderPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="620.0" prefWidth="520.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<center>
<VBox BorderPane.alignment="CENTER">
<children>
<MenuBar>
<menus>
<Menu mnemonicParsing="false" text="File">
<items>
<MenuItem mnemonicParsing="false" text="Close" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Edit">
<items>
<MenuItem mnemonicParsing="false" text="Delete" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Help">
<items>
<MenuItem mnemonicParsing="false" text="About" />
</items>
</Menu>
</menus>
</MenuBar>
<TreeTableView prefHeight="556.0" prefWidth="520.0">
<columns>
<TreeTableColumn prefWidth="270.0" text="C1" />
</columns>
</TreeTableView>
<HBox spacing="20.0" VBox.vgrow="ALWAYS">
<children>
<TextField />
<TextField />
<Region prefHeight="27.0" prefWidth="47.0" HBox.hgrow="ALWAYS" />
<Button mnemonicParsing="false" text="Add" />
</children>
<VBox.margin>
<Insets bottom="8.0" left="8.0" right="8.0" top="8.0" />
</VBox.margin>
</HBox>
</children>
</VBox>
</center>
</BorderPane>
最后但同样重要的是，这是我在尝试启动应用程序时遇到的错误：
Exception in Application start method
java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:464)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:363)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:567)
at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1051)
Caused by: java.lang.RuntimeException: Exception in Application start method
at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication(LauncherImpl.java:195)
at java.base/java.lang.Thread.run(Thread.java:830)
Caused by: javafx.fxml.LoadException:
/Users/c-mon/IdeaProjects/Guccifer%20copy/out/production/Guccifer/sample/sample.fxml
at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2625)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2603)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3237)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3194)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3163)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3136)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3113)
at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3106)
at sample.Main.start(Main.java:17)
at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1(LauncherImpl.java:846)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait(PlatformImpl.java:455)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater(PlatformImpl.java:428)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater(PlatformImpl.java:427)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
Caused by: java.lang.NullPointerException
at sample.Controller.initialize(Controller.java:43)
at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573)
... 14 more
Exception running application sample.Main
您的 tableView 和 col1 未绑定到布局标签，因此 NPE 发生在 tableView.setRoot() 中。
您应该对这两个元素执行此操作：<TreeTableView prefHeight="556.0" prefWidth="520.0" fx:id="tableView"> 然后从 FXML 创建的 TreeTableView 将写入控制器的 tableView 字段。