Android How to Program Chapter 02 Solution Manual

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2 Android Market and App
Business Issues
Objec t ives
In this chapter you’ll be
introduced to:
■ Characteristics of great
Android apps.
■ User interface guidelines for
designing your apps.
■ Registering for Android
Market.
■ Submitting your apps to
Android Market.
■ Pricing your apps and the
benefits of free vs. paid apps.
■ In-app billing.
■ Launching Android Market
from within an app.
■ Marketing and monetizing
your apps.
■ Other Android app stores.
■ Other popular mobile and
Internet app platforms to
which you can port your
apps.
■ Android humor.
2 Chapter 2 Android Market and App Business Issues
Self Review Exercises
2.1 Fill in the blanks in each of the following statements:
a) The is a reverse chronological history of all of the activities, allowing the
user to navigate to the previous activity using the Back button.

b) Selecting the Context menu from within a message in the Messaging app (by touching
and holding—also called —within the message on a touchscreen) brings
up a menu of options specific to that message, including Select all, Select text, Cut all,
Copy all, Paste and Input method.

c) To sell your apps on Android Market, you’ll need a merchant account.

d) Before uploading your app to a device, to Android Market or to other app marketplaces,
you must digitally sign the .apk file (Android app package file) using a that
identifies you as the author of the app.

e) The Android Market allows you to manage your account and your apps,
check users’ star ratings for your apps (0 to 5 stars), track the overall number of installs
of each app and the number of active installs (installs minus uninstalls).

2.2 State whether each of the following is true or false. If false, explain why.
a) Android provides four generalized screen sizes (small, normal, large and extra large) and
densities (low, medium, high and extra high), making it easier for you to design apps
that work on multiple screens.

b) A splash screen usually resembles the app’s user interface—often just an image of the
background elements of the GUI.

c) When an app works perfectly using the emulator on your computer, it will run on your
Android device.

d) You might use a licensing policy to limit how often the app checks in with the server,
how many simultaneous device installs are allowed, and what happens when an unlicensed
app is identified.

e) The title of your app as it will appear in Android Market must be unique among all Android
apps.

f) According to a study by app store analytics firm Distimo (www.distimo.com/), the average
price of paid Android apps is around $36.20.

g) According to Google, apps that use in-app billing earn profoundly more revenue than
paid apps alone.

Exercises 3
h) If you choose to sell your apps through other app marketplaces, several third-party mobile
payment providers can enable you to build in-app purchase into your apps using
APIs from mobile payment providers.

Exercises
2.3 Fill in the blanks in each of the following statements:
a) are displays of timely information on the user’s Home screen, such as the
current weather, stock prices and news.

b) are reusable components used to build an app’s user interface. They perform
actions such as searching, viewing information and dialing a phone number. A
separate one is often associated with each different screen of an app.

c) The menu—accessed through the device’s Menu button—provides actions
and operations for the app’s current screen.

d) If your app takes a while to load, use a —an image that will be displayed
when the icon is tapped on the screen so that the user sees an immediate response while
waiting for the app to load.

e) The file, referred to as the manifest, provides information needed to run
your app in Android and to filter it properly in Android Market.

f) An is an agreement through which you license your software to the user.
It typically stipulates terms of use, limitations on redistribution and reverse engineering,
product liability, compliance with applicable laws and more.

g) The , which is installed with the ADT Plugin for Eclipse, helps you debug
your apps running on actual devices.

h) According to a recent study by AdMob, is the number one reason why
users purchase a paid app.

2.4 State whether each of the following is true or false. If false, explain why.
a) You must design your app for every possible screen size and density.

screen size and density.
b) Use a BroadcastReceiver to easily share data from your app with other apps on the device.

c) The functionality of these sensors—accelerometer, barometer, compass, light sensor
and proximity sensor—is not available on the emulator.

4 Chapter 2 Android Market and App Business Issues
d) You should “obfuscate” any apps you upload to Android Market to encourage reverse
engineering of your code.

engineering of your code and further protect your apps. The ProGuard tool—
which runs when you build your app in release mode—shrinks the size of your .apk
file and optimizes and obfuscates the code.
e) According to AdMob (www.admob.com/), Android users who purchase apps download
an average of five apps per month.

f) There are now more free apps for Android than iPhone.

g) Approximately 90% of apps on Android Market are free, and they comprise the vast
majority of downloads.

h) According to comScore, YouTube and Facebook each account for 10% of all time spent
online worldwide.