java - 将图像添加到 JFrame 中？

Question

我无法让程序绘制图像。我不确定它是如何工作的，但我已经定义了paintComponent(Graphics g)，但程序似乎没有检测到它。我做错了什么吗？

这是我的代码

import java.util.Scanner;

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

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

//add actionlistener event later
public class ZodiacKiller extends JPanel{
  private JFrame mainframe;
  private Choice month;
  private Choice day;
  private Label desc;
  private Label dayDesc;
  private int monthSelect;
  private int daySelect;
  private Button calc;
  private Image[] images;
  private String[] zodiacNames = {"aquarius","pisces","aries","taurus","gemini","cancer","leo","virgo","libra","scorpio","saggitarus","capricorn"};
  private Image imageSelect;
  public ZodiacKiller(){
    guiProgram();
  }
  public static void main(String[] args){
    ZodiacKiller ted = new ZodiacKiller();
  }


  public void guiProgram(){
    mainframe = new JFrame("Zodiac Days 2016");
    mainframe.setSize(485,300);
    mainframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    mainframe.setBackground(Color.WHITE);

    //figure out how layouts work in general
    mainframe.setLayout(new FlowLayout());
    Container c = mainframe.getContentPane();

    desc = new Label("Enter your month");
    mainframe.add(desc);

    month = new Choice();
    month.add("1");
    month.add("2");
    month.add("3");
    month.add("4");
    month.add("5");
    month.add("6");
    month.add("7");
    month.add("8");
    month.add("9");
    month.add("10");
    month.add("11");
    month.add("12");
    mainframe.add(month);
    month.addItemListener(new ItemListener(){
        public void itemStateChanged(ItemEvent ie){

          monthSelect = Integer.parseInt(month.getSelectedItem());
          dayGenerator(monthSelect);
          buttonGenerator();
        }
    });
    dayDesc = new Label("Enter your day");
    mainframe.add(dayDesc);
    mainframe.setVisible(true);
  }
  public void buttonGenerator(){
    mainframe.setVisible(false);
    if(calc != null){
      mainframe.remove(calc);
      calc = null;
      oldChoiceDeleter();
    }
    calc = new Button("Calculate!");
    mainframe.add(calc);
    calc.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent evt){
        daySelect = Integer.parseInt(day.getSelectedItem());
        Zodiac teddie = new Zodiac(daySelect, monthSelect);
        imageMount(teddie.zodiacCalc());
        repaint();
        System.out.println("everything works!");
      }
    });
    mainframe.setVisible(true);
  }
  public void dayGenerator(int monthSelect){

    mainframe.setVisible(false);

    if(day != null){
      mainframe.remove(day);
      day = null;
      oldChoiceDeleter();

    }
    day = new Choice();
    day.add("1");
    day.add("2");
    day.add("3");
    day.add("4");
    day.add("5");
    day.add("6");
    day.add("7");
    day.add("8");
    day.add("9");
    day.add("10");
    day.add("11");
    day.add("12");
    day.add("13");
    day.add("14");
    day.add("15");
    day.add("16");
    day.add("17");
    day.add("18");
    day.add("19");
    day.add("20");
    day.add("21");
    day.add("22");
    day.add("23");
    day.add("24");
    day.add("25");
    day.add("26");
    day.add("27");
    day.add("28");
    day.add("29");
    switch(monthSelect){
      case 1: case 3: case 5: case 7: case 8: case 10: case 12:
        day.add("30");
        day.add("31");
      case 4: case 6: case 9:
        day.add("30");
      default:

    }
    mainframe.add(day);
    mainframe.setVisible(true);
  }
  //start here
  public void imageMount(int output){
    images = new Image[12];
    for (int i = 1; i<=12;i++){
      Image temp = (new ImageIcon("img/no" + i + ".jpeg")).getImage();
      images[i-1] = temp;
    }
    imageSelect = images[output - 1];
    System.out.println(zodiacNames[output-1] + "\n" + output);
    //make sure the image selection process works.


  }
  public static void oldChoiceDeleter(){
    return;
  }
  public static void cmdPrompt(){
    Scanner kb = new Scanner(System.in);
    System.out.println("Day?");
    int day = kb.nextInt();
    System.out.println("Month? (1 ~ 12)");
    int month = kb.nextInt();
    Zodiac tedCruz = new Zodiac(day, month);
    System.out.println(tedCruz.zodiacCalc());
  }
  @Override
  public void paintComponent(Graphics g){
    super.paintComponent(g);
    g.drawImage(imageSelect, 50, 50, null);
    System.out.println("I went here!");
  }
}

Answer 1

JFrame 不是绘制图像的最佳位置。

根据this question and answer ，您可能需要考虑以下方法之一:

• 使用带有图标的JLabel。
• 使用包含 JCustomComponent 实例的 JPanel，该实例是一个扩展 JComponent 并覆盖 paintComponent() 的类。绘制所需图像的方法。