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如何利用JOptionPane編寫一個加，減，乘，除計算器

Java

冥月1 2016-10-11 21:49:41

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2 回答

已采納

阿旭_

TA貢獻217條經(jīng)驗獲得超353個贊

import?java.awt.Rectangle;

import?javax.script.ScriptEngineManager;
import?javax.script.ScriptException;
import?javax.swing.JButton;
import?javax.swing.JFrame;
import?javax.swing.JLabel;
import?javax.swing.JPanel;
import?javax.swing.JTextField;

public?class?Test67?{

	public?static?void?main(String[]?args)?{
		JFrame?frame?=?new?JFrame("計算任意公式");

		JLabel?mJLabel_1?=?new?JLabel("請輸入要計算的公式,如:(3+2)*5");
		mJLabel_1.setBounds(new?Rectangle(18,?53,?250,?38));

		final?JLabel?mJLabel_2?=?new?JLabel("");
		mJLabel_2.setBounds(new?Rectangle(18,?117,?250,?38));

		final?JTextField?jf1?=?new?JTextField(20);
		jf1.setBounds(new?Rectangle(18,?91,?250,?25));

		JButton?jb?=?new?JButton("確認");
		jb.setBounds(new?Rectangle(18,?107?*?2?-?53,?150,?38));
		jb.addActionListener(new?java.awt.event.ActionListener()?{
			public?void?actionPerformed(java.awt.event.ActionEvent?e)?{
				double?value?=?0;
				try?{
					value?=?(double)?new?ScriptEngineManager().getEngineByName("js").eval(jf1.getText());
					mJLabel_2.setText(""?+?value);
				}?catch?(ScriptException?e1)?{
					e1.printStackTrace();
					mJLabel_2.setText("請輸入正確公式");
				}
			}
		});

		JPanel?p?=?new?JPanel();?//?建立一個面板
		p.add(mJLabel_1,?null);
		p.add(mJLabel_2,?null);
		p.add(jf1);
		p.setLayout(null);
		p.add(jb);

		frame.add(p);//?將面板添加到窗口
		frame.setSize(300,?300);//?設(shè)置窗口大小
		frame.setAlwaysOnTop(true);//?設(shè)置窗口始終在最上層
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//?設(shè)置默認的關(guān)閉操作，關(guān)閉窗口后退出程序
		frame.setLocationRelativeTo(null);//?設(shè)置窗口居中
		frame.setVisible(true);//?設(shè)置窗口可見,盡快調(diào)用paint()方法
		frame.setResizable(false);
	}
}

1 反對回復(fù) 2016-10-12

阿旭_

TA貢獻217條經(jīng)驗獲得超353個贊

import?javax.script.ScriptEngine;
import?javax.script.ScriptEngineManager;
import?javax.script.ScriptException;
import?javax.swing.JOptionPane;

public?class?Test68?{
	public?static?void?main(String[]?args)?{
		String?str?=?(String)?JOptionPane.showInputDialog(null,?"請輸入要計算的公式,如:(3+2)*5",?"title",?JOptionPane.PLAIN_MESSAGE,?null,?null,?"");
		try?{
			ScriptEngineManager?mScriptEngineManager?=?new?ScriptEngineManager();
			ScriptEngine?mScriptEngine?=?mScriptEngineManager.getEngineByName("js");
			double?value?=?(double)?mScriptEngine.eval(str);
			JOptionPane.showMessageDialog(null,?"結(jié)果為:"+value,?"標題",JOptionPane.PLAIN_MESSAGE);??
		}?catch?(ScriptException?e1)?{
			e1.printStackTrace();
			JOptionPane.showMessageDialog(null,?"請輸入正確公式",?"標題",JOptionPane.ERROR_MESSAGE);??
		}
	}
}