appletcolorexam.java

Java程序设计实用教程源代码 本书源代码按章分别放置在不同的文件夹中,所有程序均在JDK1.6环境下编译运行正常,除了第13章需要建立ODBC数据源之外,其他程序只要有Java运行环境即可直接运行

import java.applet.*;
import java.awt.*;
import java.awt.event.*; 
public class appletColorExam extends Applet implements ActionListener {
  TextField t1, t2, t3; //3个文本框分别用户输入R、G、B颜色值
  Button btn1, btn2;
  public void init() {
    Label l1 = new Label("输入R：(0~255)");
    Label l2 = new Label("输入G：(0~255)");
    Label l3 = new Label("输入B：(0~255)");
    t1 = new TextField(10);
    t2 = new TextField(10);
    t3 = new TextField(10);
    btn1 = new Button("前景");
    btn2 = new Button("背景");
    setLayout(new FlowLayout());
    Panel p = new Panel(new GridLayout(4,2));
    p.add(l1);
    p.add(t1);
    p.add(l2);
    p.add(t2);
    p.add(l3);
    p.add(t3);
    p.add(btn1);
    p.add(btn2); 
    add(p);
    btn1.addActionListener(this);
    btn2.addActionListener(this);
  }
  public void paint(Graphics g) {
    g.drawString("字体和图形颜色为applet前景色", 15, 120);
    g.fillOval(20,130,170,70);
  }
  public void actionPerformed(ActionEvent e) {
    int R, G, B;
    R = Integer.parseInt(t1.getText().toString());
    G = Integer.parseInt(t2.getText().toString());
    B = Integer.parseInt(t3.getText().toString());
    Color myColor = new Color(R, G, B);
    if (e.getActionCommand() == "背景") {
      this.setBackground(myColor); //设置Applet的背景色
    }
    if (e.getActionCommand() == "前景") {
      this.setForeground(myColor); //设置Applet的前景色
    }
  }
}