Week 8: Programming Assignment 7

Released Monday, June 30th, 2014Due Monday, July 14th, 2014

In this assignment, you will implement a program that downloads imagesusing Bound Services and then displays them in the context of the UIThread. The user can optionally select one of two different BoundServices whose implementations you will complete:

. A DownloadBoundServiceSync that uses on the Android Interface Definition Language (AIDL) and Binder framework to download files in a Bound Service that communicates synchronously with the DownloadActivity.

. A DownloadBoundServiceAsync that uses on the Android Interface Definition Language (AIDL) and Binder framework to download files in a Bound Service that communicates asynchronously with the DownloadActivity.

In this directory you'll find Java source code, AndroidManifest.xml,and associated XML metadata files. The directoryW8-A7-ThreadedDownloads-StartedServices/src/edu/vuum/mocca/ containsthe skeleton Java code that you'll implement by completing the "TODO -You fill in here" comments to provide a working solution. DO NOTCHANGE THE OVERALL STRUCTURE OF THE SKELETON - just fill in the "TODO- You fill in here" portions!!!

The main goal of this project is to understand the pattern-orientedthreaded download application and how to start and interact with BoundServices using AIDL and the underlying Binder IPC mechanisms. Inparticular, you'll need to do the following:

. Understand the protocol for launching, connecting, interacting with, and shutting down Bound Services, as described in these videos:

Section 2: Module 1: Part 7: Programming Bound Services (Part 1) Section 2: Module 1: Part 8: Programming Bound Services (Part 2)

. Understand how to program the DownloadActivity, DownloadBoundServiceSync, and DownloadBoundServiceAsync classes to launch the Bound Services using Intents, establish connections via callbacks, and send/receive typed messages from the using AIDL and the Binder IPC mechanisms, which are covered in these videos:

. Section 2: Module 1: Part 9: Programming Bound Services with AIDL (which will be available shortly on the Coursera website)

. Another overview of AIDL is available (starting at timestamp 7:00) in the video at https://class.coursera.org/android-001/lecture/85

. More detailed coverage of AIDL and Binder RPC (starting at timestamp 40:18) in the video at

https://www.youtube.com/watch?v=PvRTTvLOzag&list=PLZ9NgFYEMxp50tvT8806xllaCbd31DpDy&index=20

. Additional discussion of Advanced Bound Service Communication is

available in the video at

https://www.youtube.com/watch?v=N3bZWje8KQc&list=PLZ9NgFYEMxp50tvT8806xllaCbd31DpDy&index=21

. Understand factory methods and implement the makeIntent() factory methods in each service, which are similar to the UniqueIDGeneratorService.makeIntent() factory method covered in these videos:

Section 2: Module 1: Part 7: Programming Bound Services (Part 1) Section 2: Module 1: Part 8: Programming Bound Services (Part 2)

. Understand the methods provided in the DownloadUtils class, which contains functionality that is common to both the DownloadBoundServiceSync and DownloadBoundServiceAsync classes.

These videos are available at

https://class.coursera.org/posa-002/lecture

We'll also discuss this assignment specification (and later itssolution) in the POSA MOOC "Virtual Office Hours", which are describedin item #38 at the POSA MOOC FAQ available from

http://www.courera.org/course/posa

You'll need to build this Android application in the Eclipse ADTenvironment. Unlike previous assignments, this program isuser-driven, so output will vary depending on which URL is provided.In addition to using the default URL (which is available fromhttps://d396qusza40orc.cloudfront.net/posa/ka.png) you should alsotest this application by finding an Internet URL to an image (endingin .jpg, .gif, .png etc.) and see if your application correctlydisplays the image.

We provide several JUnit tests that should test your program'sfunctionality. The unit tests test the Service classes independentlyof the DownloadActivity, and then test the overall functionality ofthe program. By default, the unit tests try to download the defaultURL and then check if the proper image was downloaded using Bitmapcomparison.

To Run the Android Application, right click on the 'W8-A7-Android'project and select [Run As] -> [Android Application]

To Run the Android Unit Test, right click on the 'W8-A7-Android-Test'project and select [Run As] -> [Android JUnit Test]

By default, the application and test program do an "offline" downloadsince students often run this code an emulator or some otherenvironment with slow/no Internet connectivity. If you'd like torun/test it in the Internet please change the DOWNLOAD_OFFLINE booleanin

W8-A7-ThreadedDownloads-StartedServices/src/edu/vuum/mocca/DownloadUtils.java

to false.