观察者/可观察的帮助!
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11-10-2019 - |
题
问候,
我一直在研究模型视图控制器的观察者/可观察的实现。我也可能滥用模式,但这是我到目前为止所做的。在我的代码中。当按下提交时,它会触发模型的makechange()。但切勿触发测试的更新()。
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Observable;
import java.util.Observer;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
public class Testing implements Observer {
public Testing() {
model.addObserver(this);
loadListener1();
}
private void loadListener1() {
view1.submitButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
model = new Model(view1.data1Field.getText(), view1.data2Field.getText());
model.makeChange();
model.notifyObservers();
}
});
}
public void update(Observable o, Object arg) { System.out.println("Notify - Observer"); }
public static void main(String[] a) { Testing testing = new Testing(); }
private View view1 = new View("1");
private Model model = new Model();
}
class View extends JFrame {
public View(String frame) {
super("Frame: " + frame);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(300, 300);
setVisible(true);
setLayout(new GridLayout(3, 2));
add(data1Label); add(data1Field);
add(data2Label); add(data2Field);
add(submitButton); add(cancelButton);
}
private final JLabel data1Label = new JLabel("Data1");
private final JLabel data2Label = new JLabel("Data2");
public final JTextField data1Field = new JTextField();
public final JTextField data2Field = new JTextField();
public final JButton submitButton = new JButton("Submit");
public final JButton cancelButton = new JButton("Cancel");
}
class Model extends Observable {
public Model() { }
public Model(String data1, String data2) {
setData1(data1);
setData2(data2);
}
public String getData1() { return data1; }
public final void setData1(String data1) { this.data1 = data1; }
public String getData2() { return data2; }
public final void setData2(String data2) { this.data2 = data2; }
public void makeChange() {
setChanged();
notifyObservers();
System.out.println("Notify - Observable");
}
private String data1;
private String data2;
}
你能引导我穿越吗?您的答复非常感谢。
谢谢,西里尔H.
解决方案
在CLAS的构造函数中测试您的寄存器本身,以实现字段初始化期间创建的模型实例。
在Action Performed的提交按钮的方法中,您创建了 新的 模型的实例,然后随后拨打此新实例,没有注册观察者的方法NotifyObservers!
尝试此代码:
private void loadListener1() {
view1.submitButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
model.setData1(view1.data1Field.getText()),
model.setData2(view1.data2Field.getText());
model.makeChange();
}
});
}
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