JavaFX：Observable和ObservableValue的事件处理（invalidated和changed）

JavaFX提供了Observable接口和ObservableValue接口， 处理invalidated（数据失效）和changed（数据更新）事件。

示例一：

自定义类继承InvalidationListener接口，当数据失效时，触发该接口的invalidated事件。

Book数据类，其中的变量分别是StringProperty类型和DoubleProperty类型。分别注册InvalidationListener接口的实现ObservableEvent类。

package javafx8.ch03.observablelist;


import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

/**
 * @copyright 2003-2023
 * @package   javafx8.ch03.observablelist
 * @file      Book.java
 * @date      2023-12-22 16:13
 * @author    qiao wei
 * @version   1.0
 * @brief     
 * @history
 */
public class Book {
    
    public Book(String isbn, String bookTitle, double price) {
        isbnProperty = new SimpleStringProperty(this, "ISBN", isbn);
        bookTitleProperty = new SimpleStringProperty(this, "Book", bookTitle);
        priceProperty = new SimpleDoubleProperty(this, "Price",  price);
        
        observableEvent = new ObservableEvent();
        isbnProperty.addListener(observableEvent::invalidated);
        bookTitleProperty.addListener(observableEvent::invalidated);
        priceProperty.addListener(observableEvent::invalidated);
    }
    
    public String getIsbn() {
        return isbnProperty.get();
    }
    
    public void setIsbn(String isbn) {
        isbnProperty.set(isbn);
    }
    
    public String getBookTitle() {
        return bookTitleProperty.get();
    }
    
    public void setBookTitle(String bookTitle) {
        bookTitleProperty.set(bookTitle);
    }
    
    public double getPrice() {
        return priceProperty.get();
    }
    
    public void setPrice(double price) {
        priceProperty.set(price);
    }
    
    public static final String ISBN = "ISBN";
    
    public static final String BOOK = "Book";
    
    public static final String PRICE = "Price";
    
    private StringProperty isbnProperty;
    
    private StringProperty bookTitleProperty;
    
    private DoubleProperty priceProperty;
    
    private ObservableEvent observableEvent;
}

ObservableEvent类，继承InvalidationListener接口：

package javafx8.ch03.observablelist;


import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.StringProperty;


/**
 * @copyright 2003-2023
 * @package   javafx8.ch03.observablelist
 * @file      ObservableEvent.java
 * @date      2023-12-22 16:22
 * @author    qiao wei
 * @version   1.0
 * @brief     
 * @history
 */
public class ObservableEvent implements InvalidationListener {

    @Override
    public void invalidated(Observable observable) {
        String name = null;
        if (observable instanceof StringProperty) {
            name = ((StringProperty) observable).getName();
        } else if (observable instanceof DoubleProperty) {
            name = ((DoubleProperty) observable).getName();
        }
        
        switch (name) {
            case Book.ISBN:
                System.out.println("ISBN------------: " + ((StringProperty) observable).getName());
                break;
                
            case Book.BOOK:
                System.out.println("OKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK");
                break;
                
            case Book.PRICE:
                System.out.println(((DoubleProperty) observable).get());
                break;
                
            default:
                break;
        }
    }
}

测试代码：

package javafx8.ch03.observablelist;


/**
 * @copyright 2003-2023
 * @package   javafx8.ch03.observablelist
 * @file      BookTest.java
 * @date      2023-12-22 16:35
 * @author    qiao wei
 * @version   1.0
 * @brief     
 * @history
 */
public class BookTest {

    public static void main(String[] args) {
        test01();
    }
    
    private static void test01() {
        Book book01 = new Book("123", "Test01", 22.55D);
        book01.setIsbn("222---");
        
        book01.setPrice(22.3d);
    }
}

运行结果：

ISBN------------: ISBN
22.3

Process finished with exit code 0

程序更新String类型、double类型数据，触发invalidated事件。