如何从 Java 中的另一个 class 获取文本字段的数据？

Question

以下是我的菜单class。当我单击“保存”按钮时，我想从 masterdetails class 的文本字段中获取值。我该怎么做？我尝试创建第二个 class 的对象并使用 getText() 检索数据，但我无法以某种方式获取它

import java.awt.*;

import javax.swing.*;
import javax.swing.JOptionPane.*;

import java.awt.event.*;

 public class menu extends JFrame implements ActionListener
{
public JMenu jb1,jb7,jb8;
public JPanel panel;
public  ImageIcon i,j;
public JFrame jf;
private JMenuBar menubar=new JMenuBar(); 
String str = null;
String str1=null;
public menu()
 {
 setTitle("Main_Screen");
 setJMenuBar(menubar);
 jb1=new JMenu("File");`enter code here`
 jb7=new JMenu("Details");
 jb8=new JMenu("Report");

 JMenuItem e=new JMenuItem("Exit");

 menubar.add(jb1);
 menubar.add(jb7);
 menubar.add(jb8);


 JMenuItem jm1=new JMenuItem("Save");
 jb1.add(jm1); 
 JMenuItem jm3=new JMenuItem("Save As");
 jb1.add(jm3); 
 JMenuItem jm4=new JMenuItem("Update");
 jb1.add(jm4); 
 JMenuItem jm5=new JMenuItem("Retrieve");
 jb1.add(jm5);
 JMenuItem jm6=new JMenuItem("Exit");
 jb1.add(jm6);



 JMenuItem jm8=new JMenuItem("Master Details");
 jb7.add(jm8);
 JMenuItem jm12=new JMenuItem("Performance Testing");
 jb7.add(jm12);
 JMenuItem jm13=new JMenuItem("Raw Materials");
 jb7.add(jm13);

 JMenuItem jm81=new JMenuItem("Generate");
 jb8.add(jm81);




  panel=(JPanel)getContentPane( );
       panel.setLayout(new BorderLayout());

       JLabel lb1=new JLabel("",i,JLabel.CENTER);
       panel.add(lb1,BorderLayout.CENTER);

e.addActionListener(this);


jm1.addActionListener(this);
jm3.addActionListener(this);
jm4.addActionListener(this);
jm5.addActionListener(this);
jm6.addActionListener(this);
jm13.addActionListener(this);

jm12.addActionListener(this);

jm8.addActionListener(this);
jm81.addActionListener(this);

}

public void actionPerformed(ActionEvent a)
{

    String str=a.getActionCommand();
    if(str.equals("Master Details"))
    {
    masterdetails f=new masterdetails();
    f.setSize(800,600);
    f.setVisible(true);
    f.show();

    }

    if(str.equals("Save"))
    {
    masterdetails m=new masterdetails();

    //m.setSize(800,600);
    //m.setVisible(true);
    //m.show();

    }

}


 public static void main(String args[])
 {
 menu m=new menu();
 m.setSize(800,600);
 m.setVisible(true);
 m.show();
 }
 }

大师详情class如下

import java.awt.Font;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import java.awt.*;

import javax.swing.*;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.DateTime;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.eclipse.ui.forms.widgets.FormToolkit;
import org.eclipse.wb.swt.SWTResourceManager;


public class masterdetails extends JFrame implements ActionListener {

    public JPanel panel;
    public JLabel title,lblnumber,lblPSINo,lblmodel,lblcapacity,lblpressure,lblplungerdia;
    public JLabel lblnostrk,lblclient,lblpono,lblsize,lblstrokelen;
    public JLabel lblmotorhp,lblmotorrpm,lblmotorno,lblmake,lblpumptagno,lblitemno,lbldate;

    public JButton b1;

    public String number1="";
    public JTextField number,PSINo,model,capacity,pressure,plungerdia;
    public JTextField nostrk,client,pono,size,strokelen;
    public JTextField motorhp,motorrpm,motorno,make,pumptagno,itemno;
    DateTime date;
    Font g;

    String str=null;

    public masterdetails()
    {   g=new Font("",Font.BOLD,18);
        panel=(JPanel)getContentPane();
        panel.setLayout(null);
        title=new JLabel("Master Details");
        title.setFont(g);
        title.setBounds(325, 10, 150, 40);
        panel.add(title);

        lblnumber=new JLabel("No.");
        lblnumber.setBounds(10, 57, 87, 21);
        number=new JTextField("");
        number.setBounds(121, 57, 116, 21);     
        panel.add(lblnumber);
        panel.add(number);

        lbldate=new JLabel("Date");
        lbldate.setBounds(10, 97, 87, 21);
        panel.add(lbldate);

        lblPSINo=new JLabel("Pump SI No.");
        PSINo=new JTextField("");
        PSINo.setBounds(121, 137, 116, 21);
        lblPSINo.setBounds(10, 137, 87, 21);
        panel.add(lblPSINo);
        panel.add(PSINo);

        lblmodel=new JLabel("Model");
        model=new JTextField("");
        model.setBounds(121, 175, 116, 21);
        lblmodel.setBounds(10, 177, 87, 21);
        panel.add(lblmodel);
        panel.add(model);

        lblcapacity=new JLabel("Capacity");
        capacity=new JTextField("");
        lblcapacity.setBounds(10, 217, 87, 21);
        capacity.setBounds(121, 213, 116, 21);
        panel.add(lblcapacity);
        panel.add(capacity);

        lblpressure=new JLabel("Pressure");
        pressure=new JTextField("");
        lblpressure.setBounds(10, 257, 87, 21);
        pressure.setBounds(121, 252, 116, 21);
        panel.add(lblpressure);
        panel.add(pressure);

        lblplungerdia=new JLabel("Plunger Dia.");
        plungerdia=new JTextField("");
        lblplungerdia.setBounds(10, 297, 87, 21);
        plungerdia.setBounds(121, 291, 116, 21);
        panel.add(lblplungerdia);
        panel.add(plungerdia);

        lblnostrk=new JLabel("No.of Strk/Min");
        nostrk=new JTextField("");
        lblnostrk.setBounds(10, 337, 87, 21);
        nostrk.setBounds(121, 330, 116, 21);
        panel.add(nostrk);
        panel.add(lblnostrk);

        lblpumptagno=new JLabel("Pump Tag No.");
        pumptagno=new JTextField("");
        pumptagno.setBounds(121, 369, 116, 21);
        panel.add(pumptagno);
        lblpumptagno.setBounds(10, 369, 87, 21);
        panel.add(lblpumptagno);

        lblclient=new JLabel("Client.");
        client=new JTextField("");
        client.setBounds(430, 57, 214, 21);
        panel.add(client);
        lblclient.setBounds(335, 57, 87, 21);
        panel.add(lblclient);

        lblpono=new JLabel("P.O. No.");
        pono=new JTextField("");
        pono.setBounds(430, 96, 214, 21);
        panel.add(pono);
        lblpono.setBounds(335, 96, 87, 21);
        panel.add(lblpono);

        lblsize=new JLabel("Size");
        size=new JTextField("");
        size.setBounds(430, 137, 214, 21);
        panel.add(size);
        lblsize.setBounds(335, 137, 87, 21);
        panel.add(lblsize);

        lblstrokelen=new JLabel("Stroke Length");
        strokelen=new JTextField("");
        strokelen.setBounds(430, 175, 214, 21);
        panel.add(strokelen);
        lblstrokelen.setBounds(335, 175, 87, 21);
        panel.add(lblstrokelen);

        lblmotorhp=new JLabel("Motor H.P.");
        motorhp=new JTextField("");
        motorhp.setBounds(430, 213, 214, 21);
        panel.add(motorhp);
        lblmotorhp.setBounds(335, 213, 87, 21);
        panel.add(lblmotorhp);

        lblmotorrpm=new JLabel("Motor RPM");
        motorrpm=new JTextField("");
        motorrpm.setBounds(430, 252, 214, 21);
        panel.add(motorrpm);
        lblmotorrpm.setBounds(335, 252, 87, 21);
        panel.add(lblmotorrpm);

        lblmotorno=new JLabel("Motor No.");
        motorno=new JTextField("");
        motorno.setBounds(430, 291, 214, 21);
        panel.add(motorno);
        lblmotorno.setBounds(335, 291, 87, 21);
        panel.add(lblmotorno);

        lblmake=new JLabel("Make");
        make=new JTextField("");
        make.setBounds(430, 330, 214, 21);
        panel.add(make);
        lblmake.setBounds(335, 330, 87, 21);
        panel.add(lblmake);

        lblitemno=new JLabel("Item No.");
        itemno=new JTextField("");
        itemno.setBounds(430, 369, 214, 21);
        panel.add(itemno);
        lblitemno.setBounds(335, 369, 87, 21);
        panel.add(lblitemno);

        b1=new JButton("Next");
        b1.setBounds(671, 507, 75, 25);
        panel.add(b1);
        b1.addActionListener(this);


    }

    @Override
    public void actionPerformed(ActionEvent a) {

        // TODO Auto-generated method stub

        String str=a.getActionCommand();

        if(str.equals("Next"))
        {

        performancetest f=new performancetest();
        f.setSize(800,600);
        f.setVisible(true);
        f.show();

        }


    }
    public static void main(String args[])
    {
    masterdetails f=new masterdetails();
            f.setVisible(true);
            f.setSize(800,600);
            f.show();
    }





}

Answer 1

为了保持封装，我建议您在具有 Textfield 的 class 中为相关字符串创建一个 getter。此方法应该是 public 并且只有 return Textfield 具有的文本。

然后您可以通过简单地在适当的对象上调用它来从另一个 class 访问它。

示例：

public class A{
    private B b;


    private void someMethod(){
        //This will receive the Text of the Textfield!
        String text = b.getTextfieldValue();
    }
}


public class B{
    private JTextField text;

    public String getTextfieldValue(){
        return text.getText();
    }
}

Answer 2

我建议在 masterdetails class 中添加一个 public 方法 getDetails()，它将 return 文本字段的值作为数组或对象（任何你想要的）。

现在在menuclass的actionPerformed方法中提取if语句外的局部变量f并初始化为null。现在在 if(str.equals("Save")) 部分首先检查 f 是否不是 null 并调用 f.getDetails() 以获取文本字段的值以执行任何您想执行的操作。

如何从 Java 中的另一个 class 获取文本字段的数据？

How to fetch data of textfield from another class in Java?

java

eclipse

swing

jframe

jtextfield