如何以编程方式锁定Android的文件夹？ [英] How to lock Android folder programmatically?

问题描述

我想提出一个Android应用程序，我想prevent用户打开某个文件夹。在该文件夹中，用户可以存储的图像或视频文件。这将是巨大的，如果我能保护该文件夹的密码。

I am making an Android application, and I want to prevent users from opening some folder. In that folder user can store image or video files. It would be great if I could protect that folder with password.

这是做到这一点的最好方法是什么？

Which is the best way to do that?

推荐答案

下面是这两个函数加密和SD卡中的文件夹进行解密文件。 我们无法锁定文件夹，但我们可以在Android中使用AES加密文件，它可以帮助你。

Here is Both function for encrypt and decrypt file in Sdcard folder. we can not lock folder but we can encrypt file using AES in Android, it may help you.

static void encrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
    // Here you read the cleartext.
    FileInputStream fis = new FileInputStream("data/cleartext");
    // This stream write the encrypted text. This stream will be wrapped by another stream.
    FileOutputStream fos = new FileOutputStream("data/encrypted");

    // Length is 16 byte
    SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(), "AES");
    // Create cipher
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.ENCRYPT_MODE, sks);
    // Wrap the output stream
    CipherOutputStream cos = new CipherOutputStream(fos, cipher);
    // Write bytes
    int b;
    byte[] d = new byte[8];
    while((b = fis.read(d)) != -1) {
        cos.write(d, 0, b);
    }
    // Flush and close streams.
    cos.flush();
    cos.close();
    fis.close();
}

static void decrypt() throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
    FileInputStream fis = new FileInputStream("data/encrypted");

    FileOutputStream fos = new FileOutputStream("data/decrypted");
    SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(), "AES");
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(Cipher.DECRYPT_MODE, sks);
    CipherInputStream cis = new CipherInputStream(fis, cipher);
    int b;
    byte[] d = new byte[8];
    while((b = cis.read(d)) != -1) {
        fos.write(d, 0, b);
    }
    fos.flush();
    fos.close();
    cis.close();
}

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