JavaFX 单选控件

下拉单选列表（ChoiceBox）

基本应用

ChoiceBox<String> choiceBox = new ChoiceBox<>();
choiceBox.getItems().addAll("str1","str2","str3");
//也可以直接设置list，在show以后也可以动态修改
//ObservableList<String > list = FXCollections.observableArrayList();
//list.addAll("大名","小刘");
//choiceBox.setItems(list);
choiceBox.getSelectionModel().select(2);//默认选择第3个，可不设置
AnchorPane an = new AnchorPane();
an.getChildren().addAll(choiceBox);
primaryStage.setScene(new Scene(an));
primaryStage.setWidth(300);
primaryStage.setHeight(300);
primaryStage.show();
choiceBox.show();//不用点击就显示下拉选项（如果不调用该方法，则需要点击才显示下拉选择，不调用才比较正常）
//监听选中的选项
choiceBox.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<String>() {
    @Override
    public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
    }
});

如果Item不是String类型的处理

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.ChoiceBox;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
import javafx.util.StringConverter;
public class TestApp extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {
        Student s1 = new Student("小明",12);
        Student s2 = new Student("大明",20);
        ChoiceBox<Student> choiceBox = new ChoiceBox<>();
        choiceBox.getItems().addAll(s1,s2);
        choiceBox.setConverter(new StringConverter<Student>() {
            @Override
            public String toString(Student object) {
                String str = object.name + object.year;
                //这样选项就会显示为str，而不是object内存地址
                return str;
            }
            @Override
            public Student fromString(String string) {
                //不用重写
                return null;
            }
        });
        AnchorPane an = new AnchorPane();
        an.getChildren().addAll(choiceBox);
        primaryStage.setScene(new Scene(an));
        primaryStage.setWidth(300);
        primaryStage.setHeight(300);
        primaryStage.show();
    }
    class Student{
        String name;
        int year;
        public Student(String name, int year) {
            this.name = name;
            this.year = year;
        }
    }
    public static void main(String[] args) {
        launch();
    }
}

数据源排序

    @Override
    public void start(Stage primaryStage) throws Exception {
        ChoiceBox<String> choiceBox = new ChoiceBox<>();
        ObservableList<String > list = FXCollections.observableArrayList();
        list.addAll("大名子","小刘","西瓜籽儿");
        choiceBox.setItems(list);
        //没有限制在show之前才能调用，在任何时候都可以进行排序，会直接体现在UI上
        list.sort(new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o1.length() - o2.length();
            }
        });
        AnchorPane an = new AnchorPane();
        an.getChildren().addAll(choiceBox);
        primaryStage.setScene(new Scene(an));
        primaryStage.setWidth(300);
        primaryStage.setHeight(300);
        primaryStage.show();
    }

单选项（RadioButton

    @Override
    public void start(Stage primaryStage) throws Exception {
        RadioButton r1 = new RadioButton("r1");
        RadioButton r2 = new RadioButton("r2");
        RadioButton r3 = new RadioButton("r3");
        RadioButton r4 = new RadioButton("r4");
        //必须要设置这个，否则无法单选
        ToggleGroup group = new ToggleGroup();
        group.getToggles().addAll(r1,r2,r3,r4);
//        r1.setToggleGroup(group);//作用一致
//        r2.setToggleGroup(group);
//        r3.setToggleGroup(group);
//        r4.setToggleGroup(group);
        group.selectToggle(r3);//默认选中r3
        group.selectedToggleProperty().addListener(new ChangeListener<Toggle>() {
            @Override
            public void changed(ObservableValue<? extends Toggle> observable, Toggle oldValue, Toggle newValue) {
                RadioButton btn = (RadioButton) newValue;
                System.out.println(btn.getText());
            }
        });
        HBox box = new HBox();
        box.getChildren().addAll(r1,r2,r3,r4);
        AnchorPane root = new AnchorPane();
        root.getChildren().addAll(box);
        primaryStage.setScene(new Scene(root));
        primaryStage.setHeight(400);
        primaryStage.setWidth(600);
        primaryStage.show();
    }