You can perform many file operation in Android. I described few of them here.

• Create directory
• Create directory and sub-directories in one instance
• Rename directory
• Delete directory
• List the contain of that directory

The code for the first one, create a single directory at the root of your external storage directory.

File dirMain = new File(extdir + File.separator + "com.acomputerengineer");
if(!dirMain.exists())   {
  boolean mkdir = dirMain.mkdir();
  if(mkdir)   {
    Log.e("test", "Directory " + dirMain.getPath() + " created successfully");
  }
  else if(!mkdir) {
    Log.e("test", "Directory " + dirMain.getPath() + " not created");
  }
}

Result:

 

Now creating directory and sub-directories at the same time.

//example 1
File dirWithSubdir1 = new File(extdir + File.separator + "com.acomputerengineer" + File.separator + "testDir1" + File.separator + "testSubdir1");
if(!dirWithSubdir1.exists()) {
  dirWithSubdir1.mkdirs();
}

//example 2
File dirWithSubdir2 = new File(extdir + File.separator + "com.acomputerengineer" + File.separator + "testDir2" + File.separator + "testSubdir2" + File.separator + "testSubSubdir2");
if(!dirWithSubdir2.exists()) {
  dirWithSubdir2.mkdirs();
}

Result:

 

Now rename the directory ‘dirWithSubdir1’ from the above example.

File renameDir = new File(extdir + File.separator + "com.acomputerengineer" + File.separator + "newTestDir1");
dirWithSubdir1.renameTo(renameDir);

Result:

 

Now deleting the directory.

dirWithSubdir1.delete();

Result:

 

Now listing the content of the directory by logging them into logcat.

String[] dirMainFiles = dirMain.list();
for (int i = 0; i < dirMainFiles.length; i++)   {
  Log.e("test", "file " + i + " :" + dirMainFiles[i]);
}

Result: