android中有这么些个SystemService，挨个儿了解
Service大全
ACCESSIBILITY_SERVICE //加速器
ACCOUNT_SERVICE
ACTIVITY_SERVICE
ALARM_SERVICE
AUDIO_SERVICE
CLIPBOARD_SERVICE
CONNECTIVITY_SERVICE
DEVICE_POLICY_SERVICE
DISPLAY_SERVICE
DOWNLOAD_SERVICE
DROPBOX_SERVICE
INPUT_METHOD_SERVICE
INPUT_SERVICE
KEYGUARD_SERVICE
LAYOUT_INFATER_SERVICE
LOCATION_SERVICE
MEDIA_ROUTER_SERVICE
NFC_SERVICE
NOTIFICATION_SERVICE
NSD_SERVICE
PWOER_SERVICE
SEARCH_SERVICE
SENSOR_SERVICE
STORAGE_SERVICE
TELEPHONY_SERVICE
TEXT_SERVICES_MANAGER_SERVICE
UI_MODE_SERVICE
USB_SERVICE
USER_SERVICE
VIBATOR_SERVICE
WALLPAPER_SERVICE
WIFI_P2P_SERVICE
WIFI_SERVICE
WINDOW_SERVICE
用例：context.getSystemService(Context.CONNECTIVITY_SERVICE)
补充：移动开发 , Android ,
