I was trying to create a file to save pictures from the camera, it turns out that I can't create the file. But I really can't find the mistake. Can you have a look at it and give me some advice?

    private File createImageFile(){
            File imageFile=null;
            String stamp=new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
            File dir= Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
            String imageFileName="JPEG_"+stamp+"_";
            try {
                imageFile=File.createTempFile(imageFileName,".jpg",dir);
            } catch (IOException e) {
                Log.d("YJW",e.getMessage());
            }
            return  imageFile;
        }

And I have added the permission.

The method always gives such mistakes:

open failed: ENOENT (No such file or directory)