android原生获取文件的大小

根据文件路径计算文件大小

1.计算文件大小

    public static String getAutoFileOrFilesSize(String filePath) {
      File file = new File(filePath);
      long blockSize = 0;
      try {
        if (file.isDirectory()) {
          blockSize = getFileSizes(file);
        } else {
          blockSize = getFileSize(file);
        }
      } catch (Exception e) {
        e.printStackTrace();
        Log.e("获取文件大小","获取失败!");
      }
      // 根据文件自动计算单位
      return FormetFileSize(blockSize);
      // 指定单位
       return FormetFileSizeForType(blockSize, SIZETYPE_KB);
    }

2. 不指定转换类型 根据文件大小自动换算B、KB 、MB、GB

    private static long getFileSize(File file) throws Exception {
      long size = 0;
      if (file.exists()) {
        FileInputStream fis = null;
        fis = new FileInputStream(file);
        size = fis.available();
      } else {
        file.createNewFile();
        Log.e("获取文件大小","文件不存在!");
      }
      return size;
    }
    
   /**
   * 获取指定文件夹
   *
   * @param f
   * @return
   * @throws Exception
   */
  private static long getFileSizes(File f) throws Exception {
    long size = 0;
    File flist[] = f.listFiles();
    for (int i = 0; i < flist.length; i++) {
      if (flist[i].isDirectory()) {
        size = size + getFileSizes(flist[i]);
      } else {
        size = size + getFileSize(flist[i]);
      }
    }
    return size;
  }
  
    /**
   * 转换文件大小
   *
   * @param fileS
   * @return
   */
  private static String FormetFileSize(long fileS) {
    DecimalFormat df = new DecimalFormat("#.00");
    String fileSizeString = "";
    String wrongSize = "0B";
    if (fileS == 0) {
      return wrongSize;
    }
    if (fileS < 1024) {
      fileSizeString = df.format((double) fileS) + "B";
    } else if (fileS < 1048576) {
      fileSizeString = df.format((double) fileS / 1024) + "KB";
    } else if (fileS < 1073741824) {
      fileSizeString = df.format((double) fileS / 1048576) + "MB";
    } else {
      fileSizeString = df.format((double) fileS / 1073741824) + "GB";
    }
    return fileSizeString;
  }

3. 转换文件大小指定转换的类型

    public static final int SIZETYPE_B = 1;//获取文件大小单位为B的double值
    public static final int SIZETYPE_KB = 2;//获取文件大小单位为KB的double值
    public static final int SIZETYPE_MB = 3;//获取文件大小单位为MB的double值
    public static final int SIZETYPE_GB = 4;//获取文件大小单位为GB的double值
  /**
   * 转换文件大小,指定转换的类型
   *
   * @param fileS  // 文件地址
   * @param sizeType  // 类型
   * @return
   */
  private static double FormetFileSizeForType(long fileS,int sizeType) {
    DecimalFormat df = new DecimalFormat("#.00");
    double fileSizeLong = 0;
    switch (sizeType) {
      case SIZETYPE_B:
        fileSizeLong = Double.valueOf(df.format((double) fileS));
        break;
      case SIZETYPE_KB:
        fileSizeLong = Double.valueOf(df.format((double) fileS / 1024));
        break;
      case SIZETYPE_MB:
        fileSizeLong = Double.valueOf(df.format((double) fileS / 1048576));
        break;
      case SIZETYPE_GB:
        fileSizeLong = Double.valueOf(df.format((double) fileS / 1073741824));
        break;
      default:
        break;
    }
    return fileSizeLong;
  }