The reference from your manifest to the Receiver classes are not right. Right now, you reference them like they are a normal class within your package. Since they are inner classes, you should reference them like this (see the android:name
attribute):
<receiver
android:name=".MainActivity$OkBatteryReceiver"
android:enabled="false" >
<intent-filter>
<action android:name="android.intent.action.BATTERY_OKAY" />
</intent-filter>
</receiver>
Inner classes are referenced by the $
.