通过 getter/setter 将数据传递给其他类

Question

我在将数据从 GUI 传递到其他 classes 时遇到问题。一切都在 GUI 中初始化，然后数据从那里传递到另一个 class，可能会发生其他更改：（编译的简化和缺失部分）

class GUI extends JFrame {
final Configuration conf = new Configuration();

GUI() {
    initComponents();
}

private void initComponents() {

    //Setup default values
    conf.expectFires(false);
    conf.expectRain(false);
    conf.expectDisaster(true);

    JComboBox<String> seasonTypes = new JComboBox<>(new String[]{"Winter", "Spring", "Summer", "Fall"});

    seasonTypes.setSelectedIndex(0);
    conf.setSeason(seasonTypes.getItemAt(seasonTypes.getSelectedIndex()));

    //Action listener for dynamic changes to whatever is selected
    seasonTypes.addActionListener(e -> {
        String season = seasonTypes.getSelectedItem().toString();
        if (!season.equals(""))
            conf.setSeason(season);
    });

    pack();
    setLocationRelativeTo(getOwner());
    setVisible(true);
}
}

数据应该保存到我的配置 class，这是一个 getter/setter class。我无法检索任何数据，除非我将其设置在相同的 class:

主要class:

public class Main {

public static void main(String[] args) {
    Configuration conf = new Configuration();

    //code for GUI not included but pretend the GUI is called here

    //data does not come out it's basically unset.
    System.out.println("Data from GUI: [season]"+ conf.getSeason()+ " Season expectations: " + conf.expectations());

    //yet this works just fine. 
    conf.setSeason("Summer");
    System.out.println("What's the last season set?: " + conf.getSeason()); 
}
}

Answer 1

看起来您正在创建 Configuration class 的两个实例。一个在 GUI 中，一个在你的 Main class 中。这些不共享。

如果您想使用 GUI 中的 Configuration，请尝试在 GUI class 中为您的 Configuration 添加一个 getter

public Configutation getConfig()
{
     return conf;
}

然后在你的主要尝试中：

public class Main {

    public static void main(String[] args) {
    //code for GUI not included but pretend the GUI is called here
    // Assuming something like:
    GUI gui = new GUI();

    Configuration conf = gui.getConfig();

    System.out.println("Data from GUI: [season]"+ conf.getSeason()+ " Season expectations: " + conf.expectations());
    }
}

另一种选择是将 Configuration 创建为单例 - 然后您将获得相同的实例，而不是每次都实例化一个新实例。 Here is an example of how to do this

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