Pro Android with Kotlin

106
CHAPTER 7: Permissions
The question is, how would we know which permissions exactly we need for our app? The 
answer has three parts.

Android Studio tells you about a permission your app needs. If you, 
for example, write the following, Android Studio tells you a certain 
permission is required (Figure 
7-1
):
val uri = CallLog.Calls.CONTENT_URI
val cursor = contentResolver.query(
uri, null, null, null, null)

During development and testing, your app crashes and in the logs you 
see an entry like this:
Caused by: java.lang.SecurityException: Permission
Denial: opening provider
com.android.providers.contacts.CallLogProvider
from
ProcessRecord{faeda9c 4127:de.pspaeth.cp1/u0a96}
(pid=4127, uid=10096) requires
android.permission.READ_CALL_LOG or
android.permission.WRITE_CALL_LOG

The list of system permissions tells you that you need a certain 
permission for a certain task. See Table 
7-1
.
Figure 7-1. Android Studio telling you about a permission requirement
Once the usage of the permission is declared in the top-level element , 
it still must be connected to the app’s components. This happens either inside the 
 element if you want to connect the permission to all components at once 
or, better, on a per-component base. In either case you declare the permission inside the 
permission attribute, as follows:
...
"com.example.myapp.ExampleActivity"
android:permission=
"com.eample.myapp.abcPermission"/>
...

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107
CHAPTER 7: Permissions
Table 7-1. System Permissions
Permission
Group
Description
READ_CALENDAR
CALENDAR
Allows for reading the calendar. Manifest entry:
android.permission.READ_CALENDAR
WRITE_CALENDAR
CALENDAR
Allows for writing the calendar. Manifest entry:
android.permission.READ_CALENDAR
CAMERA
CAMERA
Allows for accessing the camera. Manifest entry:
android.permission.CAMERA
READ_CONTACTS
CONTACTS
Read from the contacts table. Manifest entry:
android.permission.READ_CONTACTS
WRITE_CONTACTS
CONTACTS
Write into the contacts table. Manifest entry:
android.permission.WRITE_CONTACTS
GET_ACCOUNTS
CONTACTS
Allows for listing accounts from the Accounts Service. 
Manifest entry:
android.permission.GET_ACCOUNTS
ACCESS_FINE_LOCATION
LOCATION
Allows an app to access fine-grained location. Manifest 
entry:
android.permission.ACCESS_FINE_LOCATION
ACCESS_COARSE_LOCATION
LOCATION
Allows an app to access approximate location. Manifest 
entry:
android.permission.ACCESS_COARSE_LOCATION
RECORD_AUDIO
MICROPHONE
Allows for recording audio. Manifest entry:
android.permission.RECORD_AUDIO
READ_PHONE_STATE
PHONE
Allows read access to phone state (phone number of the 
device, current cellular network information, the status 
of any ongoing calls, and a list of any PhoneAccounts 
registered on the device). Manifest entry:
android.permission.READ_PHONE_STATE
READ_PHONE_NUMBERS
PHONE
Read access to the device’s phone number. Manifest 
entry:
android.permission.READ_PHONE_NUMBERS
CALL_PHONE
PHONE
Allows an application to initiate a phone call without 
going through the dialer user interface. Manifest entry:
android.permission.CALL_PONE
ANSWER_PHONE_CALLS
PHONE
Allows an application to answer an incoming phone call. 
Manifest entry:
android.permission.ANSWER_PHONE_CALLS
(continued)

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