公共代码参考（SDCard）

package com.fredric.util;

/*-
 * SD卡操作的工具类封装
 */

import java.io.File;
import android.os.Environment;
import android.os.StatFs;

public class SDCardUtils {

    //判断SA卡是否被正常加载
    //Environment是android一个访问环境变量的类
    //MEDIA_MOUNTED SD卡正常挂载
    //MEDIA_REMOVED 无介质
    //MEDIA_UNMOUNTED 有介质，未挂载
    //MEDIA_BAD_REMOVAL SD卡被取出
    //MEDIA_CHECKING 正在磁盘检查
    //MEDIA_SHARED 操作打开USB存储
    //MEDIA_UNMOUNTABLE 存在介质损坏
    public static boolean isSDCardEnable(){
        return Environment.getExternalStorageState()
                .equals(Environment.MEDIA_MOUNTED);
    }

    //获取SD卡路径
    public static String getSDCardPath(){
        return Environment.getExternalStorageDirectory().getAbsolutePath()
                + File.separator; //增加‘/‘
    }

    //获取SA卡当前容量(单位M)
    public static long getSDCardSize(){
        if(isSDCardEnable()){

            StatFs stat = new StatFs(getSDCardPath());
            //getBlockCount 为SD卡总block数
            //getAvailableBlocks SD卡上可用的block数
            long num  = (long) stat.getAvailableBlocks();
            long size = (long)stat.getBlockSize();
            return (num * size)/1024/1024;

        }else{
            return 0;
        }
    }

}