Java Jlabel更新文本

Question

1.I am making a cookie click clone i know so mature I'm only 12 and I'm testing my abilities. I have a problem I'm trying to get a label to update but it just won't tried everything Also sorry in advance for weird indentation and messiness I'm not great at making good looking code class

package learning;


 import java.awt.Component;
 import java.awt.Dimension;
    import java.awt.Font;
 import java.awt.Graphics;
 import java.awt.event.MouseEvent;
   import java.awt.event.MouseListener;
   import javax.swing.*;
   import javax.swing.JPanel;



public class Learning extends JFrame implements MouseListener {
int clicks;
boolean Update;
/**
 * @param args the command line arguments
 */
public static void main(String[] args) {


    new Learning().start();





}
 public void start(){

      ImageImplement panel = new ImageImplement(new ImageIcon("Cookie.jpg").getImage());   
      add(panel);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    setVisible(true);
     setSize(600,600);
     setResizable(false);
      JLabel Click = new JLabel("Clicks: " + clicks);
      Click.setFont(new Font("Arial",Font.PLAIN , 20));

      panel.add(Click);
      Click.setSize(100,100);

      Click.setVisible(true);
      addMouseListener(this);
     if(Update == true){
         Click.setText("Clicks: "+ clicks);
         System.out.println("Reached");
     }


}
@Override
public void mouseClicked(MouseEvent e) {
  clicks += 1;
  System.out.println(clicks);

  Update = true;
  if(Update = true){

          Update = false;
  }
}

@Override
public void mousePressed(MouseEvent e) {

}

@Override
public void mouseReleased(MouseEvent e) {

}

@Override
public void mouseEntered(MouseEvent e) {

}

@Override
public void mouseExited(MouseEvent e) {

}













}

Other picture class

package learning;

import java.awt.Dimension;
 import java.awt.Graphics;
 import java.awt.Image;
 import javax.swing.JPanel;


class ImageImplement extends JPanel {
private Image img;




public ImageImplement(Image img) {

    this.img = img;
    Dimension size = new Dimension(img.getWidth(null), img.getHeight(null));
    setPreferredSize(size);
    setMinimumSize(size);
setMaximumSize(size);
setSize(size);
    setLayout(null);
}

@Override
public void paintComponent(Graphics g){
    g.drawImage(img, 0, 0, getWidth(), getHeight(), null);

}
}

Answer 1

Problem #1

Swing, like most GUI's, is event driven, that is something happens and you respond to it. This makes your program non-linear (the code doesn't progress in a straight line).

Events can happen at any time for a multitude of reasons, depending on the event. This means...

if(Update == true){
     Click.setText("Clicks: "+ clicks);
     System.out.println("Reached");
}

Will never be true , because the event has not occurred at the time the program interprets this command

Problem #2

To over come this issue, your mouseClicked event handler will need to know about the objects you want to update. Currently, you are declaring your variables within a local scope, within the start method...

public void start(){
    //...
    ImageImplement panel = new ImageImplement(new ImageIcon("Cookie.jpg").getImage());   
    //...
    JLabel Click = new JLabel("Clicks: " + clicks);
}

You will need to change these so that they are accessible at a class instance level

public class Learning extends JFrame implements MouseListener {
    int clicks;
    boolean Update;
    private ImageImplement panel;
    private JLabel Click

    public void start(){
        //...
        //ImageImplement panel = new ImageImplement(new ImageIcon("Cookie.jpg").getImage());   
        panel = new ImageImplement(new ImageIcon("Cookie.jpg").getImage());   
        //...
        //JLabel Click = new JLabel("Clicks: " + clicks);
        Click = new JLabel("Clicks: " + clicks);
    }

This will allow you to access these objects from any method within any instance of the current class.

Then, within your mouseClicked handler, you can update the Click label...

@Override
public void mouseClicked(MouseEvent e) {
    clicks += 1;
    Click.setText("Clicks: "+ clicks);
}

Problem #3

Mouse events are contextual to the component that the MouseListener is registered. This means a few things, but in your case, it's possible that the JLabel and ImageImplement could potentially block block mouse events from reaching the component that the MouseListener is registered to.

Instead, it might be better to add the MouseListener to the ImageImplement instead...

addMouseListener(panel);

Additional

• JLabel is capable of displaying images, unless you're playing on doing some kind of image manipulation or graphical effect, it might just be easier to use it instead.
• You should be calling super.paintComponent in your ImageImplement 's paintComponent before doing any additional painting.
• You should avoid using setPreferred/Minimum/MaximumSize and instead, override these methods as you need to achieve your desired results