library/src/main/java/net/rdrei/android/dirchooser/DirectoryChooserFragment.java
private int createFolder() {
        if (mNewDirectoryName != null && mSelectedDir != null
                && mSelectedDir.canWrite()) {
            final File newDir = new File(mSelectedDir, mNewDirectoryName);
            if (newDir.exists()) {
                return R.string.create_folder_error_already_exists;
            } else {
                final boolean result = newDir.mkdir();
                if (result) {
                    return R.string.create_folder_success;
                } else {
                    return R.string.create_folder_error;
                }
            }
        } else if (mSelectedDir != null && !mSelectedDir.canWrite()) {
            return R.string.create_folder_error_no_write_access;
        } else {
            return R.string.create_folder_error;
        }
    }
private int createFolder() {
        if (mNewDirectoryName != null && mSelectedDir != null
                && mSelectedDir.canWrite()) {
            final File newDir = new File(mSelectedDir, mNewDirectoryName);
            if (newDir.exists()) {
                return R.string.create_folder_error_already_exists;
            } else {
                final boolean result = newDir.mkdir();
                if (result) {
                    return R.string.create_folder_success;
                } else {
                    return R.string.create_folder_error;
                }
            }
        } else if (mSelectedDir != null && !mSelectedDir.canWrite()) {
            return R.string.create_folder_error_no_write_access;
        } else {
            return R.string.create_folder_error;
        }
    }
Creates a new folder in the current directory with the name
CREATE_DIRECTORY_NAME.