From app I gave the required permission for my app. While my app is running, I went to system settings page and revoked the permission. The app is crashing. Will we be able to handle this?.
Android 6.0 (Marshmallow, API 23) switched from an install-time permission model to a runtime permission model. Now instead of the user granting all permissions at runtime, you the developer are responsible for requesting permissions at runtime and responding appropriately.
You should begin by reading the Requesting Permissions at Run Time documentation. So that you can properly request permissions on devices running Marshmallow.
To prevent your app from crashing, you need to call ContextCompat.checkSelfPermission() to see if you have a permission before attempting to call a method that requires a permission. However, this is only half the equation since you still need to request the permission if you don't already have it.
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I've set my app to target AP 29 and removed requestLegacyExternalStorage=true from manifest.
Now I'm checking if the user has this permission and if result is denied I request for permission.
My problem is that the request for permission is returning Granted without showing the prompt... I know the flow is working since I'm able to read the GPS location from picture after being granted.
I see permission status = Denied and as soon as I explicitly request this permission, it returns Granted without any user interaction.
Eveything looks OK but I'm confused about not seeing the prompt... is this expected? I saw this permission qualifies as "Dangerous" so I was expecting a prompt. I'm testing on a Android 10 device.
I'm not showing any code since the project is Xamarin and the permission logic is handled through a third party library, don't think my code will help as the platform logic to request the permission is hidden by the component.
From
Android 10: fetch the gallery via MediaStore with location information :
This requires holding the ACCESS_MEDIA_LOCATION permission. Note, this permission is not "user visible in the settings UI" (source), which means the user won't see a popup asking for permission, even though it is a runtime permission. This means you have to ask for permission during runtime (in contrast to just the manifest file) but the user won't have to consent to it. Adding this here because you might be wondering why no extra UI popups are shown.
I'm still getting my head around the logic though. I'm in favour of the user being asked for permission but I don't understand why it should be necessary to "request" it if the user doesn't actually grant permission.
I was able to reproduce the issue in a simpler app. I have posted a slightly different question with code snippets.
This is an answer by HilaryN that I believe should not have been deleted (I removed the off-topic bits).
I have an Android app that requires permission to read/write from/to external storage. When the app starts, it prompts the user to allow permission for external storage (and a bunch of other services - location, camera, etc).
Here's how we do it:
ActivityCompat.requestPermissions(this, new String[]{WRITE_EXTERNAL_STORAGE, CAMERA,ACCESS_FINE_LOCATION,INTERNET,WRITE_SETTINGS,ACCESS_WIFI_STATE,READ_PHONE_STATE}, PERMISSION_REQUEST_CODE)
Now, there is also an authentication service for which we need to read from external storage. We call this authentication service during startup.
Now, problem is: When you run the app for the 1st time after install, this call to authentication service may happen often before the permission to external storage is given. Because the authentication service has no permission to external storage, it fails authentication.
Workaround we do now: manually enable permission after install and then run the app. Not a long term solution though.
I did some reading and it seems in older API's we can force the permissions to be done during apk install itself. I am on API 29. Is it possible here to prompt the user to give permissions during install itself?
I also understand that this is considered a critical service and we can't bypass permissions. Rather we cannot force permissions to be default.
What I've done for now:
Initialized the authentication service later in the code so it runs only after permissions are done.
Is there a better solution available? Like some way to either force permissions for external storage by default or some other way? From what I have read, it doesnt look possible for the latest Android version. However, if there is a way to do this, pls let me know.
Thanks,
Anand
In order to know if the user has allowed or not the application with your requested permissions, you should override onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray).
This way, you can do something like this :
if (requestCode == PERMISSION_REQUEST_CODE) {
for (elem in grantResults) {
if (elem != PackageManager.PERMISSION_GRANTED)
// Abort your feature here
}
// Do your feature here
}
If every permission has been passed you can then do what you want.
The Android Developer Documentation has a nice tutorial, more complete than I've done above, but you get the idea.
Not possible to force permission at installation time, you would need to target API level < 23 but now you need to use 28/29 to create/update apps on PlayStore. You could consider to use an alternative storage location like getCacheDir() moving files where you need later when your app has permission or just getExternalFilesDir() path where you can read/write without additional permissions.
Is it possible here to prompt the user to give permissions during install itself?
From official doc:
If the device is running Android 6.0 (API level 23) or higher, and the app's targetSdkVersion is 23 or higher, the user isn't notified of any app permissions at install time.
Also:
If the device is running Android 5.1.1 (API level 22) or lower, or the app's targetSdkVersion is 22 or lower while running on any version of Android, the system automatically asks the user to grant all dangerous permissions for your app at install-time (see figure 2).
In any case pay attention to this point:
Beginning with Android 6.0 (API level 23), users can revoke permissions from any app at any time, even if the app targets a lower API level.
In other word it means that today you have to check for and request permissions in your code.
Initialized the authentication service later in the code so it runs only after permissions are done.
You can use the ContextCompat.checkSelfPermission also in a Service.
When you start the service you can check if the permission is granted and avoid to fail.
You can use ActivityCompat.requestPermissions only in an Activity, but you can use the callback onRequestPermissionsResult to start your service.
Is there a better solution available?
You can't force the permission but for example your Service can check for permissions it needs and if it hasn't been granted yet, you can create a friendly notification to inform user.
Critical permissions like read/write external storage, camera, SMS, contacts, and a few others cannot be forcefully asked for prior to installation. So, they've to be asked for at runtime. The best practice is to ask for them just when they're actually needed instead of asking for them all at a time in the beginning.
If your service uses one of those permissions, you've to check for that permission every time before starting the service and then start the service only if the permission is granted. Otherwise, ask for permission, override onActivityResult and then start service only if the permission is granted.
Also, keep in mind to handle the scenario when the user marks the checkbox "Don't ask again" and denies permission. In that case, the user won't see the prompt again. So, you'll have to open permission settings using intent.
Instead of the interactive/runtime permissions, how can I set the permissions at install OR sticky permission so that this doesnt come up everytime I run the app.
The two permissions are LOCATION & CAMERA.
In general you request permissions in your manifest file so that the user can agree when he installs the application.
However, there has been a change recently in Android 6.0 which requires that the user is asked at runtime if the permission is dangerous. The android.permission.CAMERA permission is on of those dangerous permissions. As noted by mmBs you could set your target API level to less than Android 6.0 (e.g. 21 = 5.0) to achieve backwards compatible behaviour. But I would recommend to always update the target API level to the latest platform.
Nevertheless, you can take photos by capturing the photo using an intent (https://developer.android.com/training/camera/photobasics.html). That way your app doesn't need the CAMERA permission (the other app invoked by your intent does, but not yours).
One of our developers made android application with all permission in manifest.xml (ACCESS_FINE_LOCATION, USE_FINGERPRINT ect.).
I guided him to remove unnecessary permission then he told me, "It is safe, because he used android 6.0 run-time permission (pop up the permission)".
But I think it is not safe because it can be abused.
Do I think wrong?
There are two kind of permissions, normal and dangerous. All declared normal permissions are in effect if declared in the manifest.If the app min sdk is Android 6.0 and above, until the user grants the permissions at runtime, the dangerous permissions are not in effect. It doesn't matter if they are declared in the manifest.It may be dangerous if the user grants the app dangerous permissions and you allow other apps to access some resources using your apps permissions like PendingIntent.
As suggested by Cao Minh Vu
It is better to request permissions which your app really requires.If you request a permission that is not required by your app users may think your app is malware.
For Example:
If you are requesting permissions for camera which is not required for your App even though giving permission or denying it is up to the user but it may cause user to be skeptical.And Probably user may uninstall your Application.
I'm developing an application that going to be pr-installed (as a system app) on the firmware.
from the documentation so far about the relation between system apps, new permissions model, and the protection levels - I don't understand exactly when system app needs (if at all) to request user permission.
My problems starts when I try to use the WRITE_EXTERNAL_STORAGE permission. from the documentation I can see that it marked as "dangerous" permission.
- does "dangerous" permissions grant automatically to system apps?
when I use WRITE_EXTERNAL_STORAGE permission (as a system app) I'm getting security exception, and I don't know if it's mean that even tough my app installed as a system app - "dangerous" permissions must be requested by the user..
another point to mention:
to check the app behavior as a system app, I'm installing my application APK on the sys-priv directory (the device is rooted) of a nexus 5 running SDK preview 3. this is when I'm getting the security exception when attep to use methods requires the external storage permission..
After a lot of digging and debugging, I finally found some clue of granting runtime permission on marshmallow for system app, with a lot of inspirations in this stackoverflow ticket.
The key logic is in DefaultPermissionGrantPolicy. After systemReady, PackageManagerService checks if this user's default runtime permissions are not set yet(i.e. this is a new user), if so, PackageManagerService calls DefaultPermissionGrantPolicy.grantDefaultPermissions() to check/grant permissions:
public void grantDefaultPermissions(int userId) {
grantPermissionsToSysComponentsAndPrivApps(userId);
grantDefaultSystemHandlerPermissions(userId);
}
There are two cases that your built-in app may be automatically granted with runtime permission.
A> grantPermissionsToSysComponentsAndPrivApps -> will grant runtime permission with FLAG_PERMISSION_SYSTEM_FIXED and FLAG_PERMISSION_GRANTED_BY_DEFAULT.
if your system app has uid<10000, you will be granted with permissions for your user group.
if your system app fits all below conditions, it will be granted the permissions.
is a privilegedApp (under /system/priv-app/)
is persistent (android:persistent="true")
signed with platform signature.
B> grantDefaultSystemHandlerPermissions -> will grant runtime permission with FLAG_PERMISSION_GRANTED_BY_DEFAULT .
If your app is considered as a "default platform handler app", (i.e. your app is "expected to work out-of-the-box", like camera, dialer, SMS, calendar .etc, you can read more in method grantDefaultSystemHandlerPermissions()).
Other than that, your system application needs to ask user for granting dangerous permission, as long as it has targetSdk set to 23.
Quoting the release notes for the 2nd M preview:
Apps included in the system image are no longer granted dangerous permissions automatically. All apps should check for and request permissions at runtime.
That fits with what I recall seeing when I first used the stock Camera app on a Nexus 5 with the final(?) 6.0 preview firmware — it too asked for the runtime permission.
So, AFAIK, system apps have to ask for runtime permissions, as do non-system apps.