Can't create folder on external storage on android

Question

My development phone is a Nexus 5, running Android 4.4.2.

In my application, I am attempting to create a folder on external storage that wi

Answer 1

For android sdk version 23 and above you should check if the user has granted permission of external storage.

private void createFolder() {
    if (isStoragePermissionGranted()) {
        File folder = new File(Environment.getExternalStorageDirectory()+ File.separator + "DebugData");

        if(!folder.exists()){
            folder.mkdir();
        }
    }

public  boolean isStoragePermissionGranted() {
    if (Build.VERSION.SDK_INT >= 23) {
        if (checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            return true;
        } else {
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
            return false;
        }
    }
    else { //permission is automatically granted on sdk<23 upon installation
        return true;
    }
}

The code above worked for me and I hope it will work for you.