Pro Android with Kotlin

10
CHAPTER 2: Application
The most important attribute of the root entry 

is called 
package
. It declares the ID 
of your app, and if you plan to publish your app, this must be a worldwide unique ID for it. 
A good idea is to use your domain (or your company’s domain) reversed and then an unique 
application identifier, as shown in the previous code.
Table 
2-1
 describes all the possible attributes of 

. Note that for the simplest apps, 
all you need is the 
package
attribute and a single 

child.
Table 2-1. 
Manifest Main Attributes
Name
Description
android: installLocation
Defines the installation location. Use 
internalOnly
for installing 
only in the internal storage, 
auto
for letting the OS decide with 
affinity toward using the internal storage (the user can switch 
later in the system settings), or 
preferExternal
for letting the OS 
decide with affinity toward using the external storage. The default 
is 
internalOnly
. Note that a couple of restrictions apply to using 
external storage for that aim; see the online documentation for 

. For modern devices with lots of free internal storage, you 
should never need to specify 
preferExternal
here.
package
Defines the worldwide unique ID of your app and is a string like 
abc.
def.ghi.[...]
where the nondot characters may contain the letters 
A–Z and a–z, the numbers 0–9, and underscores. Don’t use a number 
after a dot! This is also the default process name and the default 
task affinity; see the online text companion to learn what those 
mean. Note that once your app is published, you cannot change this 
package name in the Google Play Store. There is no default; you 
must set this attribute.
android: sharedUserId
Defines the name of the Android OS user ID assigned to the app. You 
can prior to Android 8.0 or API level 26 do things such as assigning 
the same user ID to different apps, which lets them freely interchange 
data. The apps must then be signed with the same certificate. 
However, you normally don’t have to set this attribute, but if you set 
it, make sure you know what you are doing.
android: sharedUserLabel
If you also set 
sharedUserId
, you can set a user-readable label for 
the shared user ID here. The value must be a reference to a string 
resource (for example, 
@string/myUserLabel
).
android: 
targetSandboxVersion
Serves as a security level and is either 1 or 2. Starting with Android 
8.0 or API level 26, you 
must
set it to 2. With 2, the user ID can no 
longer be shared between different apps, and the default value for 
usesClearTextTraffic
(see the online text companion) is set to false.
android: versionCode
Defines an internal version number of your app. This is not shown to 
users and used only for comparing versions. Use an integer number 
here. This defaults to 
undefined
.
android: versionName
Defines a user-visible version string. This is either the string itself or 
a pointer to a string resource (
"@string/..."
). This is not used for 
anything else but informing the user.

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