test.java

自己编写的学习Java的示例代码

import java.awt.*;
import java.awt.event.*;
public class Test extends Frame 
{
	TextField text;
	public Test(){
		super("Test");
		setLayout(new FlowLayout());
		
		text = new TextField(20);
		add(text);
		
		Button b1 = new Button("1");
		Button b2 = new Button("2");
		Button badd = new Button("+");
		Button bsum = new Button("=");


		//事件委托
		TestListener listener = new TestListener();
		b1.addActionListener(listener);
		b2.addActionListener(listener);
		b1.addKeyListener(listener);
		b2.addKeyListener(listener);
		badd.addActionListener(listener);
		bsum.addActionListener(listener);
		add(b1);
		add(b2);
		add(badd);
		add(bsum);
		
		setSize(300,200);
		setVisible(true);
		setResizable(false);
	}
	public static void main(String args[]){
		new Test();
	}
	//事件处理器(按钮单击事件)
	class TestListener implements ActionListener,KeyListener
	{
		String num1="";
		String operator="";
		String upStr="";
		public void actionPerformed(ActionEvent e){
			String str = e.getActionCommand();
			if(str.equals("1")||str.equals("2")){
				if(upStr.equals("+")||upStr.equals("=")){
					text.setText("");
				}
				text.setText(text.getText()+str);
			}
			if(str.equals("+")){
				if(operator.equals("+")){
					text.setText(add(num1,text.getText()));
				}
				num1=text.getText();
				operator="+";
			}
			if(str.equals("=")){
				if(operator.equals("+")){
					text.setText(add(num1,text.getText()));
				}
			}
			upStr = str;
		}
		public String add(String num1,String num2){
			if(num1.equals("")){
				num1="0";
			}
			if(num2.equals("")){
				num2="0";
			}
			double d1 = Double.parseDouble(num1);
			double d2 = Double.parseDouble(num2);
			String sum = String.valueOf(d1+d2);
			return sum;
		}


		public void keyPressed(KeyEvent e){
			char c = e.getKeyChar();
			System.out.println(c);
		}
		public void keyReleased(KeyEvent e){

		}
		public void keyTyped(KeyEvent e){

		}

	}


}