JApplet Textfield/jbutton /嵌套循环程序,创建一个墙,在textfield中输入行数

Question

我目前正在使用JCreator,并且无法找到我的代码有什么问题,由于某种原因它不能读取我输入的内容JTextField.我不打算彻底改变我的代码,如果any1可以指出我做错了什么,或者给我一些它应该是什么样的代码示例,这将是很好的.再次,当他们做同样的事情时,不要寻找"这比这更好".

import java.awt.*;
import javax.swing.*;
import java.util.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Wall extends JApplet implements ActionListener {

    double count;
    Boolean Submit = false;
    JButton btn1;
    JTextField  tf,field;
    int x = 0;
    int y = 575;
    int x1 = 50;
    int y1 = 25;
    int textnumber;
    Random randomNum = new Random();//initialize random variable
    int count2;

    public void init() {

        setLayout( new FlowLayout( ) );
        tf = new JTextField(5);
        field = new JTextField( "<===== Enter Brick Rows 1-20", 16 );   
        add( tf );  
        add( field );
        btn1 = new JButton("Submit");
        add(btn1);
        btn1.addActionListener(this);
    }

    public void actionPerformed(ActionEvent event){

        if (event.getSource()== btn1){
            Submit = true;
        }
    }

    public void paint(Graphics g, double BrickNumbers) {

        super.paint(g);
        while(Submit == true){
            DrawBrick(g,BrickNumbers);
        }
    }

    public void DrawBrick(Graphics g, double BrickNumbers){

        String Value = tf.getText();
        BrickNumbers = Double.parseDouble(Value);

        if(Submit == true){
            count = BrickNumbers;
            for(double count = BrickNumbers; ((count>=1) && (count <=20)); count--){

                int d = 1+ randomNum.nextInt(255);//get d variable
                int e = 1+ randomNum.nextInt(255);//get e variable
                int f = 1+ randomNum.nextInt(255);//get f variable
                Color randomcolor = new Color(d,e,f);
                g.setColor(randomcolor);
                g.fillRect(x, y, x1, y1);
                g.fillRect(x+ 50, y, x1, y1);
                g.fillRect(x+100, y, x1, y1);
                g.fillRect(x+150, y, x1, y1);
                g.fillRect(x+200, y, x1, y1);
                g.fillRect(x+250, y, x1, y1);   
                y = y - 25;
            }
        }
        repaint();
    }   
}

Answer 1

你的绘画方法中有一些不好的代码,包括:

• 你的方法中有一个while(true)循环,paint(...)它会锁定你的GUI并防止它响应任何东西.
• 你试图从一个从paint方法调用的方法读入JTextField.你不应该在绘画代码或它调用的方法中有程序逻辑.
• 您不应该首先覆盖paint(...)JApplet,而应该覆盖paintComponent(...)JApplet所持有的JPanel.
• 考虑添加代码来读取actionPerformed方法中的JTextField,因为这似乎是这个逻辑的最佳位置.

编辑

• 你的paint方法永远不会被调用,因为它不是JApplet绘制方法的真正重载.你的有两个参数,一个paint方法应该只有一个.
• 在actionPerformed方法中,从JTextField获取值,
• 将它转换为一个Integer.parseInt(...)不带双精度的int,因为你永远不会画一小块砖
• 并且使用int获取set一个int类字段,可能称为brickCount或类似的东西,然后调用repaint().
• 在你的JPanel的paintComponent(...)方法(类似paint应该只有一个参数,Graphics),调用paintBricks(),并让这个方法使用brickCount字段值来决定要绘制多少砖.
• 切勿repaint()从内部paint(...) paintComponent(...)或从这些方法中调用的任何方法调用.

编辑2

这是一个不执行程序需要做的示例,但说明了如何从JTextField获取信息并在图形中使用它:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SimpleApplet extends JApplet {
   @Override
   public void init() {
      getContentPane().add(new SimpleAppletMainPanel());
   }
}

class SimpleAppletMainPanel extends JPanel {
   private static final Color CIRCLE_COLOR = Color.red.darker();
   private static final int CIRCLE_STROKE_WIDTH = 10;
   private static final int GAP = 3;
   private static final Stroke CIRCLE_STROKE = new BasicStroke((float)CIRCLE_STROKE_WIDTH);
   private JTextField textField = new JTextField(5);
   private JButton myButton = new JButton("Submit");
   private int count = 0;

   public SimpleAppletMainPanel() {
      ActionListener actionListener = new ActionListener() {
         public void actionPerformed(ActionEvent arg0) {
            try {
               count = Integer.parseInt(textField.getText());
               repaint();
            } catch (NumberFormatException e) {
               e.printStackTrace();
            }
         }
      };
      myButton.addActionListener(actionListener);
      textField.addActionListener(actionListener);
      add(new JLabel("Enter a number, 1-10:"));
      add(textField);
      add(myButton);
   }

   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      for (int i = 0; i < count; i++) {
         drawCircle(g, i);
      }
   }

   private void drawCircle(Graphics g, int layer) {
      int centerX = getWidth() / 2;
      int centerY = getHeight() / 2;
      int radius = layer * (CIRCLE_STROKE_WIDTH + GAP) + GAP;
      int x = centerX - radius ;
      int y = centerY - radius;

      Graphics2D g2b = (Graphics2D) g.create();
      g2b.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
      g2b.setStroke(CIRCLE_STROKE);

      g2b.setColor(CIRCLE_COLOR);
      g2b.drawOval(x, y, radius * 2, radius * 2);

      g2b.dispose();
   }
}

这将导致以下结果: