calculator.java

GUI 计算器功能。 超好用。

package com.javaeye.android.calculator;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.EditText;
import bsh.EvalError;
import bsh.Interpreter;

public class Calculator extends Activity {
	private static EditText et;
	private static Interpreter i = new Interpreter();
	
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);        
        et = (EditText)findViewById(R.id.edittext);
        et.append("\n");
        et.setSelection(et.length());
    }
    
    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
    	if (keyCode == KeyEvent.KEYCODE_NEWLINE) {
    		String input = et.getText().toString();
    		String lastLine = input.substring(input.lastIndexOf("\n", input.length() - 2));
    		et.append("\t\t" + eval(lastLine) + "\n");
        	et.setSelection(et.length());    		
    	}
    	return true;
    }
    
    private Object eval(String input) {
    	try {
			return i.eval(input);
		} catch (EvalError e) {
			return e.getMessage();
		}
    }
}