Checking if I can access a file in Android file file system

Question

I'm trying to cat files in Android sysfs, and first I'd like to check if the files exist, and if they are accessible. I'm trying the first step with the following Java code:

String filePath = "/sys/some/path/to/some/file";
try {
  File file = getApplicationContext().getFileStreamPath(filePath);
  if (file.exists()) {
    // do something
  } else {
    // do something else
  }
} catch (IOException e) {
        e.printStackTrace();
}

At run time, I get a java.lang.IllegalArgumentException: File /sys/some/path/to/some/file contains a path separator

What am I doing wrong, and how can I check if a file in sysfs is readable?

Follow this thread [java.lang.IllegalArgumentException: contains a path separator](http://stackoverflow.com/questions/5963535/java-lang-illegalargumentexception-contains-a-path-separator) — vivek jha, Feb 17 '17 at 07:53
OK, that thread suggests using a FileInputStream instead of File object. How then can I check for read access to a FileInputStream object? — user1118764, Feb 17 '17 at 08:12

score 0 · Answer 1 · answered Feb 17 '17 at 08:20

Try this code -

  String fileDirectory = "/sys/some/path/to/some/";
  String fileName = "file";
        try
        {
            File file = new File(fileDirectory, fileName );

            if (file.Exists()) {                    
                // do something
            }
            else
            {
                // do something else
            }
        }
        catch (IOException e)
        {

        }

score 0 · Accepted Answer · answered Feb 20 '17 at 09:49

0

I ended up using vivek's suggestion to use FileInputStream, and then checking for exceptions

answered Feb 20 '17 at 09:49

user1118764

9,255
18
61
113

Checking if I can access a file in Android file file system

2 Answers2