javascript 在面板中显示 ArrayList
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时间：2020-10-25 20:01:31 来源:igfitidea点击:
Displaying an ArrayList in a Panel
提问by Splitter
I am having this problem in below code as my ArrayList both name and values I wish to be displayed on the window is not appearing. It should be displayed at the bottom of the window but I set everything possible to setVisible true but still unable to display it. I think its a minor mistake but I cant see as it is my code. Sorry that the code is such a mess as I am writing this for my own understanding.
我在下面的代码中遇到了这个问题，因为我希望在窗口上显示的 ArrayList 名称和值都没有出现。它应该显示在窗口的底部，但我将所有可能的设置为 setVisible true 但仍然无法显示它。我认为这是一个小错误，但我看不到，因为这是我的代码。抱歉，代码是如此混乱，因为我正在编写此代码是为了我自己的理解。
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.*;
import javax.swing.*;
public class SamplePaper5a {
static final int width = 500;
static final int hight = 600;
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame frame = new JFrame("Exam");
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
frame.setSize(width,hight);
Container contain = new Container();
contain = frame.getContentPane();
contain.setLayout(new GridLayout(2,2));
final ArrayList<String>names = new ArrayList<String>();
final ArrayList<String>values = new ArrayList<String>();
names.add("dian");
names.add("maze");
names.add("carl");
names.add("John");
names.add("tan");
names.add("james");
values.add("11111");
values.add("2222");
values.add("3333");
values.add("4444");
values.add("5555");
values.add("6666");
final JTextArea txtArea = new JTextArea();
JButton butt = new JButton(" Enter ");
contain.add(txtArea);
contain.add(butt);
butt.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
for(int i=0;i<values.size();i++)
{
txtArea.setText( txtArea.getText()+" \n "+values.get(i) +" "+ names.get(i));
}
}
});
try
{
contain.add(new NamePanel2(names,values,1));
}
catch(Size2Exception e)
{
System.out.print(e);
}
frame.setVisible(true);
}
}
class NamePanel2 extends JPanel
{
ArrayList<String> names = new ArrayList<String>();
ArrayList<String> values = new ArrayList<String>();
int cols;
public NamePanel2(ArrayList<String> nam,ArrayList<String> val,int c) throws Size2Exception
{
this.names = nam;
this.values =val;
this.cols = c;
JPanel panel = new JPanel();
if(names.size()!= values.size())
throw new Size2Exception(" wrong sizes");
panel.setLayout(new GridLayout(names.size(),cols));
for(int i = 0; i<names.size();i++)
{
panel.add(new JLabel(names.get(i)));
panel.add(new JTextField(values.get(i)));
}
panel.setVisible(true);
}
}
class Size2Exception extends Exception
{
public Size2Exception(String str)
{
super(str);
}
}
回答by Andrew Thompson
See the comments for the nature of the fix + a few tips.
请参阅有关修复性质的评论 + 一些提示。
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.*;
import javax.swing.*;
public class SamplePaper5a {
static final int width = 500;
static final int hight = 600;
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame frame = new JFrame("Exam");
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
frame.setSize(width,hight);
// don't mix Swing with AWT
JPanel contain = new JPanel();
System.out.println(contain.getLayout());
frame.setContentPane(contain);
contain.setLayout(new GridLayout(2,2));
final ArrayList<String>names = new ArrayList<String>();
final ArrayList<String>values = new ArrayList<String>();
names.add("dian");
names.add("maze");
names.add("carl");
names.add("John");
names.add("tan");
names.add("james");
values.add("11111");
values.add("2222");
values.add("3333");
values.add("4444");
values.add("5555");
values.add("6666");
final JTextArea txtArea = new JTextArea();
JButton butt = new JButton(" Enter ");
contain.add(txtArea);
contain.add(butt);
butt.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
for(int i=0;i<values.size();i++)
{
txtArea.setText( txtArea.getText()+" \n "+values.get(i) +" "+ names.get(i));
}
}
});
try
{
contain.add(new NamePanel2(names,values,1));
}
catch(Size2Exception e)
{
System.out.print(e);
}
frame.setVisible(true);
}
}
class NamePanel2 extends JPanel
{
ArrayList<String> names = new ArrayList<String>();
ArrayList<String> values = new ArrayList<String>();
int cols;
public NamePanel2(ArrayList<String> nam,ArrayList<String> val,int c) throws Size2Exception
{
this.names = nam;
this.values =val;
this.cols = c;
// unnecessary
//JPanel panel = new JPanel();
// it would be better to define an Object that contains a name/value pair
if(names.size()!= values.size())
throw new Size2Exception(" wrong sizes");
setLayout(new GridLayout(names.size(),cols));
for(int i = 0; i<names.size();i++)
{
add(new JLabel(names.get(i)));
add(new JTextField(values.get(i)));
}
// unnecessary
//panel.setVisible(true);
}
}
class Size2Exception extends Exception
{
public Size2Exception(String str)
{
super(str);
}
}
Screen Shot
截屏
BTW - the GUI looks quite odd. I'll leave that for you to sort out.
顺便说一句 - GUI 看起来很奇怪。我会把它留给你解决。
