I need a valid method to check if a String represents a path for file or a directory. What are valid directory names in Android? As it comes out, folder names can contain '.' chars, so how does system understand whether there's a file or a folder?
Assuming path is your String.
File file = new File(path);
boolean exists = file.exists(); // Check if the file exists
boolean isDirectory = file.isDirectory(); // Check if it's a directory
boolean isFile = file.isFile(); // Check if it's a regular file
See File Javadoc
Or you can use the NIO class Files and check things like this:
Path file = new File(path).toPath();
boolean exists = Files.exists(file); // Check if the file exists
boolean isDirectory = Files.isDirectory(file); // Check if it's a directory
boolean isFile = Files.isRegularFile(file); // Check if it's a regular file