[SOLVED] Cs 522 assignment five—application architecture ii

In this assignment, you will build on the previous assignment in two ways:
1. You will use ViewModel as a backing store for your activities.
2. You will replace the use of ListView with the more versatile and efficient
RecyclerView. You can think of this as taking off the training wheels in your
handling of lists of data in the UI.
You should follow these guidelines for your implementation.
First, you are given the implementation of the ChatViewModel for the ChatServer
activity. Complete this activity to only access the database indirectly, through the view
model. Also complete the implementations of the view models for the other activities,
and incorporate the use of these view models into the activities.
Second, in your main activity where you displayed the messages received in a ListView,
use a RecyclerView instead. You are given an adapter MessageAdapter that uses the
Recycler.Adapter class to connect the list of messages resulting from a query to the
recycler view. The MessageAdapter class uses the layout resource R.layout.message
as the layout resource for each row in your recycler view. In the adapter class, you are
given a ViewHolder nested class that specifies the layout for each row in the list of
messages, and you should complete the adapter to specify how the text views in this
layout are initialized with data from a message (sender and message text).
The activities for viewing peer information also use recycler views (to show the list of
peers, or the list of messages from a peer). You should use the generic class
TextAdapter, which supports a list of objects that are displayed just by calling their
toString() operations. The interesting wrinkle is how to support clicking on a peer in
the list of peers, since RecyclerView does not support OnItemClickListener. See the
TextAdapter class for an approach that does this, by registering an OnClickListener
object on each row of the RecyclerView (and complete the code).
Since the point of using ViewModel is to cache the result of a database query, and re-use
it if the device orientation changes and the activity is destroyed and recreated, you need
to enable dynamic orientation changes in the device. You can do this in the display
settings of the device:
In Assignment 7, you will see how to provide different user interfaces for portrait and
landscape orientation of the device.
Submitting Your Assignment
Once you have your code working, please follow these instructions for submitting your
assignment:
1. Create a zip archive file, named after you, containing a directory with your name. E.g.
if your name is Humphrey Bogart, then name the directory Humphrey_Bogart.
2. In that directory you should provide the Android Studio projects for your apps.
In addition, record short mpeg videos of your apps working. Make sure that your name
appears at the beginning of the videos. For example, put your name in the title of the
app. Do not provide private information such as your email or cwid in the video. The
videos should demonstrate running the app from Android Studio, where the code
including the viewmodel definitions are clearly visible, exiting the app, then rerunning
the app and demonstrating that the saved state from the previous run (messages for the
chat app) are still present when the app is restarted. Make sure that you send messages
from several peers to the chat server. Also, show by logging (using the logcat window)
that a reorientation event causes the activity to be destroyed and recreated, but the view
model is not destroyed until you leave the activity. You only need to show this for the
main activity.
Your solution should be uploaded via the Canvas classroom. Your solution should
consist of a zip archive with one folder, identified by your name. Within that folder, you
should have two Android projects, for the apps you have built. You should also provide
videos demonstrating the working of your assignments, the schema generated as a Json
file by Room, as well as a completed rubric.