/**
   * 获得SD卡总大小
   *
   * @return
   */
  private String getSDTotalSize() {
    File path = Environment.getExternalStorageDirectory();
    StatFs stat = new StatFs(path.getPath());
    long blockSize = stat.getBlockSize();
    long totalBlocks = stat.getBlockCount();
    return Formatter.formatFileSize(this, blockSize * totalBlocks);
  }

  /**
   * 获得sd卡剩余容量，即可用大小
   *
   * @return
   */
  private String getSDAvailableSize() {
    File path = Environment.getExternalStorageDirectory();
    StatFs stat = new StatFs(path.getPath());
    long blockSize = stat.getBlockSize();
    long availableBlocks = stat.getAvailableBlocks();
    return Formatter.formatFileSize(this, blockSize * availableBlocks);
  }

  /**
   * 获取系统内存大小
   * @return
   */
  private String getSysteTotalMemorySize(){
    //获得ActivityManager服务的对象
    ActivityManager mActivityManager = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
    //获得MemoryInfo对象
    ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo() ;
    //获得系统可用内存，保存在MemoryInfo对象上
    mActivityManager.getMemoryInfo(memoryInfo) ;
    long memSize = memoryInfo.totalMem ;
    //字符类型转换
    String availMemStr = formateFileSize(memSize);
    return availMemStr ;
  }

  /**
   * 获取系统可用的内存大小
   * @return
   */
  private String getSystemAvaialbeMemorySize(){
    //获得ActivityManager服务的对象
    ActivityManager mActivityManager = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
    //获得MemoryInfo对象
    ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo() ;
    //获得系统可用内存，保存在MemoryInfo对象上
    mActivityManager.getMemoryInfo(memoryInfo) ;
    long memSize = memoryInfo.availMem ;

    //字符类型转换
    String availMemStr = formateFileSize(memSize);

    return availMemStr ;
  }