Question

Java 事件处理

如果按下键盘的A键时隐藏第一个窗口，弹出第二个窗口。按下按钮时退出。滑动滚轮时文字框里的文字增大或减少1。对了，import后面都接什么啊？如果都帮忙解决了，那就谢谢各位大侠了！！！！！我想这点小问题应该很容易吧！

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
//该类用了3个接口，必须实现所有方法
public class Action extends JFrame implements KeyListener,ActionListener,MouseWheelListener{
JTextArea ta;
JButton b;
JScrollPane sp;
JPanel p;
static int i = 12;
public Action(){
ta = new JTextArea("注意：滑动滚轮时此文本域里的文字大小变化(增大或减少1)");
ta.setEditable (false);//不可编辑
ta.setLineWrap (true);//自动换行
ta.setForeground (Color.BLUE);//字体颜色
sp = new JScrollPane(ta);
setFont(i);

b = new JButton("退出");
p = new JPanel(new FlowLayout(FlowLayout.RIGHT));
p.add (b);
this.add (sp,BorderLayout.CENTER);
this.add (p,BorderLayout.SOUTH);
this.setTitle ("Java事件处理");
this.setSize (400,300);
this.setLocationRelativeTo (null);//窗口居中
this.setVisible (true);
this.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
ta.addKeyListener (this);
sp.addMouseWheelListener (this);
b.addActionListener (this);
}
public void setFont(int i){
ta.setFont (new Font(Font.SERIF,Font.PLAIN,i));
sp.setBorder (BorderFactory.createTitledBorder ("字体大小:"+i));
}
public static void main(String[] args){
JFrame.setDefaultLookAndFeelDecorated (true);
new Action();
}
public void keyPressed(KeyEvent e){

if(e.getKeyText(e.getKeyCode()).equals ("A")){
if(this.isVisible ()==true){
this.setVisible (false);
}else{
this.setVisible (true);
}
JFrame f = new JFrame("新窗口");
f.setBounds(400,200,300,300);
f.setVisible (true);
}
}
public void keyReleased(KeyEvent e){}
public void keyTyped(KeyEvent e){}
public void actionPerformed(ActionEvent e){
System.exit (0);
}
public void mouseWheelMoved(MouseWheelEvent e){

if(e.getWheelRotation ()>0) i++;//滚轮向下滚每次 +1
else i--;
setFont(i);
}
}

Answer 2

AWT(⊙o⊙)？import java.awt.*;
import javax.swing.*;import java.awt.event.*;要问import后面 那可多了去了……API看看吧

Answer 3

import后面的都是java包名，你要用到那个包中的类就接那个包