Android file storage

How to create folders and modify permissions in Android

Each application package has a private data storage directory. Only the application that belongs to this package has the permission to write data to this directory. Its absolute path: /data/<package name>/directory. In addition to Private Data Directories, applications can also read and write sdcards. Third-party applications cannot be written to other system directories in the file system.

// Create a folder

File destdir = new file ("/data/<package name>/<folder> ");

If (! Destdir. exists ()){
Destdir. mkdirs ();
}

// Modify permissions

Fileoutputstream Fos;
Fos = openfileoutput ("FILENAME", mode_world_readable );

/* Mode:

Public static final int mode_private = 0x0000; // The owner can access and overwrite and save data.
Public static final int mode_world_readable = 0x0001; // The owner can access and append the data to save.
Public static final int mode_world_writeable = 0x0002;
Public static final int mode_append = 0x8000;

*/

// Sdcard. You must first determine whether the sdcard is inserted.

String status = environment. getexternalstoragestate ();
If (status. Equals (environment. media_mounted )){

Return true;
}

Else {

Return false;
}

// Obtain the absolute path of the sdcard

Enviroment. getexternalstoragedirectory ();

// Obtain the absolute path of the phone memory (/data/<pacage Name>/files)

Activity. getfilesdir ();

// Obtain the cache directory (/data/<pacage Name>/cache );

Activity. getcachedir ();