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我有一個非常艱難的時間找到任何文件，所以對於愚蠢的問題提前抱歉。我想填充一個用FXML聲明的選擇框，其中的項目是ArrayList的一部分。JavaFX FXML - 添加選項到選擇框
這裏是我的FXML：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.*?> <?import javafx.scene.control.*?> <?import java.lang.*?> <?import javafx.scene.layout.*?>
<GridPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="300.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8.0.40" fx:controller="application.LMUController"> <columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" maxWidth="600.0" minWidth="10.0" prefWidth="551.0" /> </columnConstraints> <rowConstraints>
<RowConstraints maxHeight="346.0" minHeight="10.0" prefHeight="222.0" vgrow="SOMETIMES" />
<RowConstraints maxHeight="316.0" minHeight="10.0" prefHeight="178.0" vgrow="SOMETIMES" /> </rowConstraints> <children>
<GridPane>
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" maxWidth="312.0" minWidth="0.0" prefWidth="0.0" />
<ColumnConstraints hgrow="SOMETIMES" maxWidth="443.0" minWidth="10.0" prefWidth="443.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" valignment="CENTER" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<Label contentDisplay="TOP" text="List Price" GridPane.halignment="RIGHT" GridPane.rowIndex="3">
<GridPane.margin>
<Insets right="8.0" />
</GridPane.margin>
</Label>
<Label contentDisplay="TOP" text="City" GridPane.halignment="RIGHT" GridPane.rowIndex="2">
<GridPane.margin>
<Insets right="8.0" />
</GridPane.margin>
</Label>
<Label contentDisplay="TOP" text="Address" GridPane.halignment="RIGHT" GridPane.rowIndex="1">
<GridPane.margin>
<Insets right="8.0" />
</GridPane.margin>
</Label>
<Label contentDisplay="TOP" text="Comps CSV" GridPane.halignment="RIGHT" GridPane.rowIndex="4">
<GridPane.margin>
<Insets right="8.0" />
</GridPane.margin>
</Label>
<FlowPane GridPane.columnIndex="1" GridPane.rowIndex="1">
<children>
<TextField prefWidth="308.0" />
</children>
</FlowPane>
<FlowPane GridPane.columnIndex="1" GridPane.halignment="CENTER" GridPane.rowIndex="2" GridPane.valignment="CENTER">
<children>
<ChoiceBox id="choiceCity" prefWidth="150.0">
<FlowPane.margin>
<Insets right="8.0" />
</FlowPane.margin>
</ChoiceBox>
<Button id="btnCitiesRefresh" mnemonicParsing="false" text="Refresh" onAction="#btnCitiesRefresh_action">
<FlowPane.margin>
<Insets right="8.0" />
</FlowPane.margin>
</Button>
<Button id="btnLmuPreview" mnemonicParsing="false" text="Preview" />
</children>
</FlowPane>
<FlowPane GridPane.columnIndex="1" GridPane.rowIndex="3">
<children>
<TextField id="btnListPrice" prefWidth="150.0" />
</children>
</FlowPane>
<FlowPane prefHeight="62.0" prefWidth="279.0" GridPane.columnIndex="1" GridPane.rowIndex="4">
<children>
<TextField id="txtCompsCSVPath" editable="false" prefWidth="200.0">
<FlowPane.margin>
<Insets right="8.0" />
</FlowPane.margin>
</TextField>
<Button id="btnCompsCSVBrowse" mnemonicParsing="false" text="Browse" />
</children>
</FlowPane>
</children>
</GridPane>
<GridPane GridPane.halignment="LEFT" GridPane.rowIndex="1">
<GridPane.margin>
<Insets right="8.0" />
</GridPane.margin>
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints maxHeight="91.0" minHeight="10.0" prefHeight="89.0" vgrow="SOMETIMES" />
<RowConstraints maxHeight="61.0" minHeight="10.0" prefHeight="39.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<FlowPane prefHeight="43.0" prefWidth="592.0" GridPane.rowIndex="1" GridPane.valignment="CENTER">
<children>
<Button id="btnSaveExcel" mnemonicParsing="false" text="Export to Excel">
<FlowPane.margin>
<Insets left="8.0" />
</FlowPane.margin>
</Button>
</children>
</FlowPane>
</children>
</GridPane> </children> </GridPane>
這裏是我的控制器：
package application;
import java.awt.Choice;
import java.net.URL;
import java.util.ArrayList;
import java.util.ResourceBundle;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.*;
import javafx.scene.control.MenuBar;
import javafx.scene.input.InputEvent;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.input.MouseEvent;
import localMarketUpdate.*;
public class LMUController implements Initializable{
LMUParser lmuParser;
ChoiceBox choiceCity;
@Override
public void initialize(URL location, ResourceBundle resources) {
lmuParser = new LMUParser();
}
@FXML
private void btnCitiesRefresh_action(ActionEvent event)
{
ArrayList<String> cities = lmuParser.getCities();
ObservableList<String> list = FXCollections.observableArrayList(cities);
for (int i = 0; i < cities.size(); i++){
list.add(i, cities.get(i));
//list.add(i, cities.get(i));
}
choiceCity.setItems(FXCollections.observableArrayList("One","Two","Three"));
}
}
我就行收到一個錯誤：
choiceCity.setItems(FXCollections.observableArrayList("One","Two","Three"));
引起：java.lang.NullPointerExcepti在上 application.LMUController.btnCitiesRefresh_action（LMUController.java:47） ...... 58多個
這裏的最終目標是通過填充ArrayList中的項目有ChoiceBox。這是如何完成的，我做錯了什麼？