<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>to your manifest. More info http://developer.android.com/reference/android/Manifest.permission.html#READ_EXTERNAL_STORAGE
Programming Tips - What can't my app read files?
Date: 2014mar11 OS: Android Q. What can't my app read files? I used to be able to! A. Android 4.1 removed the implied right to read files. Add: