将PDF文件从资产复制到SD卡

Question

i have built the app that opens pdf file from assests folder ,it is working properly but the file is created in internal storage.How to hide it for the user. Is there a way to store it in root folder so user cannot see it .

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    File fileBrochure = new File(Environment.getExternalStorageDirectory()+ "/" + "abc.pdf");




    if (!fileBrochure.exists())
    {
        Toast.makeText(this, "copying", Toast.LENGTH_SHORT).show();

        CopyAssetsbrochure();
    }

    /** PDF reader code */
    File file = new File(Environment.getExternalStorageDirectory()+ "/" + "abc.pdf");

    Intent intent = new Intent(Intent.ACTION_VIEW);
    intent.setDataAndType(Uri.fromFile(file),"application/pdf");

    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    try
    {

        getApplicationContext().startActivity(intent);

    }
    catch (ActivityNotFoundException e)
    {
        Toast.makeText(this, "NO Pdf Viewer", Toast.LENGTH_SHORT).show();
    }
}

private void CopyAssetsbrochure() {
    AssetManager assetManager = getAssets();
    String[] files = null;
    try
    {
        files = assetManager.list("");
    }
    catch (IOException e)
    {
        Log.e("tag", e.getMessage());
    }

    for(int i=0; i<files.length; i++)
    {
        String fStr = files[i];
        if(fStr.equalsIgnoreCase("abc.pdf"))
        {
            InputStream in = null;
            OutputStream out = null;
            try
            {
                in = assetManager.open(files[i]);
                out = new FileOutputStream(Environment.getExternalStorageDirectory()+ "/" + files[i]);
                copyFile(in, out);
                in.close();
                in = null;
                out.flush();
                out.close();
                out = null;
                break;
            }
            catch(Exception e)
            {
                Log.e("tag", e.getMessage());
            }
        }
    }
}

private void copyFile(InputStream in, OutputStream out) throws IOException {
    byte[] buffer = new byte[1024];
    int read;
    while((read = in.read(buffer)) != -1){
        out.write(buffer, 0, read);
    }
}

Answer 1

not possible. you can't get access to root.

You can achieve your requirement by making use Cryptography that is Encryption and Decryption.

Encrypt the file and store it on internal storage while reading inside the application decrypt it. You will done.

if any intruder copy your file from internal storage then he or she will unable to decrypt it.