java.lang.IllegalArgumentException: contains a path separator

The solution is:

FileInputStream fis = new FileInputStream (new File(NAME_OF_FILE));  // 2nd line

The openFileInput method doesn't accept path separators.

Don't forget to

fis.close();

at the end.

openFileInput() doesn't accept paths, only a file name if you want to access a path, use File file = new File(path) and corresponding FileInputStream

I got the above error message while trying to access a file from Internal Storage using openFileInput("/Dir/data.txt") method with subdirectory Dir.

You cannot access sub-directories using the above method.

Try something like:

FileInputStream fIS = new FileInputStream (new File("/Dir/data.txt"));

You cannot use path with directory separators directly, but you will have to make a file object for every directory.

NOTE: This code makes directories, yours may not need that...

File file= context.getFilesDir();
file.mkdir();

String[] array=filePath.split("/");
for(int t=0; t< array.length -1 ;t++)
{
    file=new File(file,array[t]);
    file.mkdir();
}

File f=new File(file,array[array.length-1]);

RandomAccessFileOutputStream rvalue = new RandomAccessFileOutputStream(f,append);

String all = "";
        try {
            BufferedReader br = new BufferedReader(new FileReader(filePath));
            String strLine;
            while ((strLine = br.readLine()) != null){
                all = all + strLine;
            }
        } catch (IOException e) {
            Log.e("notes_err", e.getLocalizedMessage());
        }

File file = context.getFilesDir(); 
file.mkdir();
String[] array = filePath.split("/"); 
for(int t = 0; t < array.length - 1; t++) {
    file = new File(file, array[t]); 
    file.mkdir();
}
File f = new File(file,array[array.length- 1]); 
RandomAccessFileOutputStream rvalue = 
    new RandomAccessFileOutputStream(f, append);

I solved this type of error by making a directory in the onCreate event, then accessing the directory by creating a new file object in a method that needs to do something such as save or retrieve a file in that directory, hope this helps!

 public class MyClass {    

 private String state;
 public File myFilename;

 @Override
 protected void onCreate(Bundle savedInstanceState) {//create your directory the user will be able to find
    super.onCreate(savedInstanceState);
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        myFilename = new File(Environment.getExternalStorageDirectory().toString() + "/My Directory");
        if (!myFilename.exists()) {
            myFilename.mkdirs();
        }
    }
 }

 public void myMethod {

 File fileTo = new File(myFilename.toString() + "/myPic.png");  
 // use fileTo object to save your file in your new directory that was created in the onCreate method
 }
}

I did like this

var dir = File(app.filesDir, directoryName)
if(!dir.exists()){
    currentCompanyFolder.mkdir()
}
var directory = app.getDir(directoryName, Context.MODE_PRIVATE)
val file = File(directory, fileName)
file.outputStream().use {
    it.write(body.bytes())
}