/* 判断SD卡是否存在 返回true表示存在 */
public boolean avaiableMedia() {
  String status = Environment.getExternalStorageState();
  if (status.equals(Environment.MEDIA_MOUNTED)) {
   return true;
  } else {
   return false;
  }
}

/* 获取SD卡可用空间 */
public long getSDFreeSize() {
  // 取得SD卡文件路径
  File path = Environment.getExternalStorageDirectory();
  StatFs sf = new StatFs(path.getPath());
  // 获取单个数据块的大小(Byte)
  long blockSize = sf.getBlockSizeLong();
  // 空闲的数据块的数量
  long freeBlocks = sf.getAvailableBlocksLong();
  // 返回SD卡空闲大小
  // return freeBlocks * blockSize; //单位Byte
  // return (freeBlocks * blockSize)/1024; //单位KB
  return (freeBlocks * blockSize) / 1024 / 1024; // 单位MB
}

/* 获取SD卡所有空间 */
public long getSDAllSize() {
  // 取得SD卡文件路径
  File path = Environment.getExternalStorageDirectory();
  StatFs sf = new StatFs(path.getPath());
  // 获取单个数据块的大小(Byte)
  long blockSize = sf.getBlockSizeLong();
  // 获取所有数据块数
  long allBlocks = sf.getBlockCountLong();
  // 返回SD卡大小
  // return allBlocks * blockSize; //单位Byte
  // return (allBlocks * blockSize)/1024; //单位KB
  return (allBlocks * blockSize) / 1024 / 1024; // 单位MB
}