http://cn.voidcc.com/question/p-avbcvnyl-bnn.html

http://cn.voidcc.com/question/p-avbcvnyl-bnn.html

https://github.com/barbeau/gpstest/blob/master/GPSTest/src/main/java/com/android/gpstest/util/GpsTestUtil.java

https://github.com/barbeau/gpstest/blob/master/GPSTest/src/main/java/com/android/gpstest/GpsStatusFragment.java

https://stackoverflow.com/questions/14222152/androids-onstatuschanged-not-working

https://stackoverflow.com/questions/5261929/android-location-api-get-provider-status

https://stackoverflow.com/questions/23496581/check-location-provider-status