Many Apps support third party login, like Facebook, Wechat, Dribbble etc. When we develop an app that need to support this feature, we need to know about OAuth protocol.

Callback is a very important feature in Java. For button click listener, it uses interface callback. I used to use interface callback often, but not very clearly understand it.

In Android development, ListView and RecyclerView are very important widgets. When I was first time to use ListView. The adapter and getView function really confused me. Functionality of adapter is to display data on the item view of the ListView. You can easily implement it follow the step in here. The following picture shows the simple principle of the adapter.

Mean Shift algorithm is the first image analysis research I did in my graduate study in 2015. It is usually used as image segmentation or tracking algorithm. This blog will start with the principle of mean shift and its image segmentation application.