简单计算器源码android实现

这个计算器功能实现比较简单，对新手有一定帮助，希望你能有所收获！

/** Automatically generated file. DO NOT MODIFY */
package com.example.calculator;

public final class BuildConfig {
    public final static boolean DEBUG = true;
}

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2016-04-26 14:57  calculator\
     文件         459  2016-04-20 08:29  calculator\.classpath
     文件         846  2016-04-20 08:29  calculator\.project
     目录           0  2016-04-26 14:57  calculator\.settings\
     文件         177  2016-04-20 08:29  calculator\.settings\org.eclipse.jdt.core.prefs
     文件        1011  2016-04-20 09:01  calculator\AndroidManifest.xml
     目录           0  2016-04-20 08:29  calculator\assets\
     目录           0  2016-05-24 09:31  calculator\bin\
     文件        1011  2016-04-26 15:02  calculator\bin\AndroidManifest.xml
     文件      240003  2016-05-24 09:31  calculator\bin\calculator.apk
     目录           0  2016-04-26 15:02  calculator\bin\classes\
     文件      558900  2016-05-24 09:31  calculator\bin\classes.dex
     目录           0  2016-04-26 15:02  calculator\bin\classes\com\
     目录           0  2016-04-26 15:02  calculator\bin\classes\com\example\
     目录           0  2016-04-26 15:02  calculator\bin\classes\com\example\calculator\
     文件         353  2016-04-26 15:02  calculator\bin\classes\com\example\calculator\BuildConfig.class
     文件        4623  2016-04-26 15:02  calculator\bin\classes\com\example\calculator\MainActivity.class
     文件         352  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$attr.class
     文件         473  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$dimen.class
     文件         625  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$drawable.class
     文件         992  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$id.class
     文件         415  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$layout.class
     文件         400  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$menu.class
     文件         484  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$string.class
     文件         443  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R$style.class
     文件         713  2016-05-24 09:31  calculator\bin\classes\com\example\calculator\R.class
     目录           0  2016-04-26 14:57  calculator\bin\dexedLibs\
     文件      189231  2016-04-20 08:49  calculator\bin\dexedLibs\android-support-v4-ea1b40bf9533310919be8470c819f0c3.jar
     文件         120  2016-05-24 09:30  calculator\bin\jarlist.cache
     目录           0  2016-04-26 14:57  calculator\bin\res\
     文件       45136  2016-05-24 09:31  calculator\bin\resources.ap_
............此处省略57个文件信息