File storage

The file storage provided by mPaaS provides file encryption capability based on Android native File.

Important: Because the file encryption uses the encryption function provided by Mobile Security Guard, you must ensure that the encryption images in Mobile Security Guard have been correctly generated.

File types

• ZFile: This type of files are stored in data/data/package_name/files.
• ZExternalFile: This type of files are stored in sdcard/Android/data/package_name/files.
• ZFileInputStream/ZFileOutputStream: File storage input/output stream, the files will not be encrypted if you use this stream.
• ZSecurityFileInputStream/ZSecurityFileOutputStream: File storage input/output stream, the files will be encrypted if you use this stream.

Examples

• Convert files to text
• Convert text to files
• Insert files
• Delete files

Convert files to text

    /**
     * Convert files to text
     * @param file: File
     * @return Text
     */
    public String file2String(File file) {
        InputStreamReader reader = null;
        StringWriter writer = new StringWriter();
        try {
            // Use decryption input stream ZSecurityFileInputStream
            // If you don’t use encryption/decryption function, then use ZFileInputStream
            reader = new InputStreamReader(new ZSecurityFileInputStream(file, this));
            //Write the input stream into the output stream
            char[] buffer = new char[DEFAULT_BUFFER_SIZE];
            int n = 0;
            while (-1 != (n = reader.read(buffer))) {
                writer.write(buffer, 0, n);
            }
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        } finally {
            if (reader != null)
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }
        //Return the coversion result
        if (writer != null) {
            return writer.toString();
        } else {
            return null;
        }
    }

Convert text to files

    /**
     * Convert text to files
     * @param res: Text
     * @param file: File
     * @return true means successful while false means failed
     */
    public boolean string2File(String res, File file) {
        boolean flag = true;
        BufferedReader bufferedReader = null;
        BufferedWriter bufferedWriter;
        try {
            bufferedReader = new BufferedReader(new StringReader(res));
            // Use decryption output stream ZSecurityFileOutputStream
            // If you don’t use encryption/decryption function, then use ZFileOutputStream
            bufferedWriter = new BufferedWriter(new OutputStreamWriter(new ZSecurityFileOutputStream(file, this)));
            //Character buffers
            char buf[] = new char[DEFAULT_BUFFER_SIZE];
            int len;
            while ((len = bufferedReader.read(buf)) != -1) {
                bufferedWriter.write(buf, 0, len);
            }
            bufferedWriter.flush();
            bufferedReader.close();
            bufferedWriter.close();
        } catch (Exception e) {
            e.printStackTrace();
            flag = false;
            return flag;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return flag;
    }

Insert files

    /**
     * Insert files
     *
     * @param file: File
     */
    private void insertFile(BaseFile file) {
        if (null == file) {
            return;
        }
        StringBuilder sb = new StringBuilder();
        String content = sb.append(file.getName())
                .append(' ')
                .append(SIMPLE_DATE_FORMAT.format(new Date(System.currentTimeMillis()))).toString();
        string2File(content, file);
        try {
            if (!file.exists()) {
                file.createNewFile();
            }
            mData.add(file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

Delete files

    /**
     * Delete files
     *
     * @param file: File
     */
    private void deleteFile(BaseFile file) {
        try {
            file.delete();
            mData.remove(file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }