Android常用文件操作

1，修改文件名称

/**
     * 文件重命名
     * 
     * @description：
     * @author ldm
     * @date 2016-6-12 下午3:20:30 参数： File f:要重命名的文件 String newName:新名称
     */
    private void reNameForFile(File f, String newName) {
        if (TextUtils.isEmpty(newName) || newName.equals(f.getName()))
            return;

        try {
            File newf = new File(f.getParent(), newName);
            if (newf.exists()) {
                Toast.makeText(getActivity(), "文件已经存在！", Toast.LENGTH_LONG)
                        .show();
            } else if (f.renameTo(newf)) {
                Toast.makeText(getActivity(), "重命名成功！", Toast.LENGTH_LONG)
                        .show();

            }
        } catch (SecurityException se) {
            Toast.makeText(getActivity(), "重命名失败！", Toast.LENGTH_LONG).show();
        }
    }

2，计算SD卡剩余容量：

    /**
     * 显示SD卡可用空间
     * 
     * @description：
     * @author ldm
     * @date 2016-6-12 下午3:06:42
     */
    @SuppressWarnings("deprecation")
    public static String calSdCardAvailable() {
        String result = "";
        if (Environment.MEDIA_MOUNTED.equals(Environment
                .getExternalStorageState())) {
            // StatFs类主要用来获取文件系统的状态
            StatFs stf = new StatFs(Environment.getExternalStorageDirectory()
                    .getPath());
            long blockSize = stf.getBlockSize();// block大小
            long blockCount = stf.getBlockCount();// bloc数目
            long availCount = stf.getAvailableBlocks();// 总大小
            return calFileSize(availCount * blockSize) + " / "
                    + calFileSize(blockSize * blockCount);
        }
        return result;
    }



----------


/**
     * 计算文件大小
     * 
     * @description：
     * @author ldm
     * @date 2016-6-12 下午3:11:46
     */
    public static String calFileSize(long size) {
        String fileSize;
        if (size < KB)
            fileSize = size + "B";
        else if (size < MB)
            fileSize = String.format("%.1f", size / KB) + "KB";
        else if (size < GB)
            fileSize = String.format("%.1f", size / MB) + "MB";
        else
            fileSize = String.format("%.1f", size / GB) + "GB";

        return fileSize;
    }

3，多个SD卡时 取外置SD卡 ，代码来自网友项目

/** 多个SD卡时 取外置SD卡 */
    public static String getExternalStorageDirectory() {
        // 参考文章
        // http://blog.youkuaiyun.com/bbmiku/article/details/7937745
        Map<String, String> map = System.getenv();
        String[] values = new String[map.values().size()];
        map.values().toArray(values);
        String path = values[values.length - 1];
        if (path.startsWith("/mnt/")
                && !Environment.getExternalStorageDirectory().getAbsolutePath()
                        .equals(path))
            return path;
        else

4，文件复制

/**
      * @description 复制文件
      * @author ldm
      * @time  2016/6/12 15:30
      * @param
   */
    public static void copyFile(File from, File to) {
        if (null == from || !from.exists()) {
            return;
        }
        if (null == to) {
            return;
        }
        FileInputStream is = null;
        FileOutputStream os = null;
        try {
            is = new FileInputStream(from);
            if (!to.exists()) {
                to.createNewFile();
            }
            os = new FileOutputStream(to);
            copyFileFast(is, os);
        } catch (Exception e) {
            throw new KJException(FileUtil.class.getClass().getName(), e);
        } finally {
            closeIO(is, os);
        }
    }

5，删除文件

/**
      * @description 删除文件
     * @author ldm
      * @time  2016/6/12 15:30
      * @param
   */
    public static void delFile(File file) {
        if (file.exists()) {
            if (file.isDirectory()) {
                for (File f : file.listFiles()) {
                    clear(f);
                    file.delete();
                }
            }
            else {
                file.delete();
            }
        }
    }