systematic
Choose one (the picture supports cropping)
http://www.cnblogs.com/mrcoke/articles/2783910.html
select multiple
Approach
The official image selector (but does not support all versions of androi, only supports API Level >=18)
http://developer.android.com/reference/android/content/Intent.html#ACTION_GET_CONTENT
Refer to the following article
http:// stackoverflow.com/questions/9379579/select-multiple-images-in-android-gallery/12806036#12806036
Original address: http://www.itmmd.com/201411/135.html
open source
https://github.com/tungdx/android-media-picker