java - 如何根据 JavaFX 中的组合框选择对按钮执行多个操作

Question

这是创建用户界面的主要类:

public class Test extends Application {

@Override
public void start(Stage primaryStage) {

    FlowPane mainPane = new FlowPane();         


    FlowPane query = new FlowPane();            
    query.setPadding(new Insets(30,30,30,30));
    query.setHgap(10);
    query.setVgap(20);

    ComboBox<String> queryDropDown = new ComboBox<>();      
    queryDropDown.getItems().addAll("Gene", "Disease");
    queryDropDown.setValue("Select One");
    System.out.println(queryDropDown.getValue());


    query.getChildren().addAll(new Label("Select Category: "), queryDropDown);


    FlowPane userInput = new FlowPane();            
    userInput.setPadding(new Insets(30,30,30,30));
    userInput.setHgap(10);
    userInput.setVgap(20);

    TextField searchField = new TextField();    
    searchField.setPrefColumnCount(3);
    userInput.getChildren().addAll(new Label("Enter Query: "), new TextField());




    FlowPane searchButtonPane = new FlowPane();         

    searchButtonPane.setPadding(new Insets(30,30,30,200));
    searchButtonPane.setHgap(50);
    searchButtonPane.setVgap(50);
    Button searchButton = new Button("Search");

    searchButtonPane.getChildren().addAll(searchButton);

    ButtonHandlerClass handler1 = new ButtonHandlerClass();     
    searchButton.setOnAction(handler1);


    mainPane.getChildren().addAll(query, userInput, searchButtonPane);      

    Scene scene = new Scene(mainPane, 300, 250);
    primaryStage.setTitle("Genetic Database");
    primaryStage.setScene(scene);
    primaryStage.show();





}


public static void main(String[] args) {
    // Prints "Hello, World" to the terminal window.
    System.out.println("Hello, World");
    Application.launch(args);



}

}

这是按钮处理程序类

public class ButtonHandlerClass implements EventHandler<ActionEvent> {

@Override
public void handle(ActionEvent e) {
    System.out.println("Button Clicked");



}

}

我希望能够让相同的“搜索”按钮根据用户在组合框中选择的选项执行不同的操作。我试过为组合框做类似于 ButtonHandlerClass 的事情。任何建议将不胜感激。

谢谢!

Answer 1

为方式 1 和方式 3 保留此事件处理程序:

           // Using an event handler
            EventHandler<ActionEvent> handler = new EventHandler<ActionEvent>() {
                @Override
                public void handle(ActionEvent arg0) {
                    String selectedItem = queryDropDown.getSelectionModel().getSelectedItem();
                    System.out.println(selectedItem);
                    // ...code
                }
            };

---

方式一:

        //note that every time one action event handler is called
        //instead for multiple handlers you can use the way 3
        searchButton.setOnAction(handler);

---

方法 2(避免创建匿名类):

    //using lambda expression
    searchButton.setOnAction(a->{
        String selectedItem = queryDropDown.getSelectionModel().getSelectedItem();
        System.out.println(selectedItem);
        // ...code      
    });

---

方式三:

(您可以添加多个事件处理程序，所有事件都会被调用)(例如您可以添加多个操作事件处理程序...)

[这是方式 1 和 方式 2 做不到的事情]:

    //adding an event handler
    searchButton.addEventHandler(ActionEvent.ACTION,handler);

    //or

    searchButton.addEventHandler(ActionEvent.ACTION,a->{
        String selectedItem = queryDropDown.getSelectionModel().getSelectedItem();
        System.out.println(selectedItem);
        // ...code      
    });

---

方式四:

使用外部类(不推荐，除非你有太多代码以至于你不希望你当前的类有太多行);( )

这里可以有不同的情况:

• 该类将嵌套到您当前的类？
• ComboBox 是全局变量，可以从嵌套的 上课？
• 如果 !2 那么你必须在 的构造函数上传递它的引用 外部类

• 有一百万种情况

  //情况3代码:

   public class ButtonHandlerClass implements EventHandler<ActionEvent> {
  
     ComboBox<String> comboBox;
  
     /**
     *Constructor
     */
     public ButtonHandlerClass(ComboBox comboBox){
  
       this.comboBox = comboBox;
  
    }
  
   @Override
    public void handle(ActionEvent e) {
       String selectedItem = queryDropDown.getSelectionModel().getSelectedItem();
              System.out.println(selectedItem);
              // ...code  
  
    }
  
   }
  
  }