通過getter / setter將數據傳遞給其他類

Question

我在將數據從GUI傳遞到其他類時遇到問題。 一切都在GUI中初始化，然后從那里將數據傳遞到另一個類，在該類中可能進行其他更改：（用於編譯的簡化部分和缺失部分）

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);
}
}

數據應該保存到我的配置類（getter / setter類）中。 我無法檢索任何數據，除非我在同一類中進行了設置：

主班：

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

看起來您正在創建Configuration類的兩個實例。 一個在GUI ，一個在您的Main類中。 這些不是共享的。

如果要從GUI使用Configuration ，請嘗試在GUI類中為Configuration添加吸氣劑

public Configutation getConfig()
{
     return conf;
}

然后在您的主要嘗試中：

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());
    }
}

另一種選擇是將Configuration創建為單例-然后您獲得相同的實例，而不是每次實例化一個新實例。 這是如何執行此操作的示例