Showing posts with label permissions. Show all posts
Showing posts with label permissions. Show all posts

Monday, December 19, 2016

Building better apps with Runtime Permissions

Building better apps with Runtime Permissions


Posted by Ian Lake, Developer Advocate

Android devices do a lot, whether it is taking pictures, getting directions or making phone calls. With all of this functionality comes a large amount of very sensitive user data including contacts, calendar appointments, current location, and more. This sensitive information is protected by permissions, which each app must have before being able to access the data. Android 6.0 Marshmallow introduces one of the largest changes to the permissions model with the addition of runtime permissions, a new permission model that replaces the existing install time permissions model when you target API 23 and the app is running on an Android 6.0+ device.

Runtime permissions give your app the ability to control when and with what context you’ll ask for permissions. This means that users installing your app from Google Play will not be required to accept a list of permissions before installing your app, making it easy for users to get directly into your app. It also means that if your app adds new permissions, app updates will not be blocked until the user accepts the new permissions. Instead, your app can ask for the newly added runtime permissions as needed.

Finding the right time to ask for runtime permissions has an important impact on your app’s user experience. We’ve gathered a number of design patterns in our new Permission design guidelines including best practices around when to request permissions, how to explain why permissions are needed, and how to handle permissions being denied.

Ask up front for permissions that are obvious

In many cases, you can avoid permissions altogether by using the existing intents system to utilize other existing specialized apps rather than building a full experience within your app. An example of this is using ACTION_IMAGE_CAPTURE to start an existing camera app the user is familiar with rather than building your own camera experience. Learn more about permissions versus intents.

However, if you do need a runtime permission, there’s a number of tools to help you. Checking for whether your app has a permission is possible with ContextCompat.checkSelfPermission() (available as part of revision 23 of the support-v4 library for backward compatibility) and requesting permissions can be done with requestPermissions(), bringing up the system controlled permissions dialog to allow the user to grant you the requested permission(s) if you don’t already have them. Keep in mind that users can revoke permissions at any time through the system settings so you should always check permissions every time.

A special note should be made around shouldShowRequestPermissionRationale(). This method returns true if the user has denied your permission request at least once yet have not selected the ‘Don’t ask again’ option (which appears the second or later time the permission dialog appears). This gives you an opportunity to provide additional education around the feature and why you need the given permission. Learn more about explaining why the app needs permissions.

Read through the design guidelines and our developer guide for all of the details in getting your app ready for Android 6.0 and runtime permissions. Making it easy to install your app and providing context around accessing user’s sensitive data are key changes you can make to build better apps.

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Thursday, December 8, 2016

Google Play services 8 1 and Android 6 0 Permissions

Google Play services 8 1 and Android 6 0 Permissions


Posted by, Laurence Moroney, Developer Advocate

Along with new platform features, Android 6.0 Marshmallow has a new permissions model that streamlines the app install and auto-update process. Google Play services 8.1 is the first release to support runtime permissions on devices running Android 6.0. and will obtain all the permissions it needs to support its APIs. As a result, your apps won’t normally need to request permissions to use them. However, if you update your apps to target API level 23, they will still need to check and request runtime permissions, as necessary.

To update your Google Play services apps to handle the latest permissions model, it’s good practice to manage the user’s expectations in setting permissions that the runtime may require. Below are some best practices to help you get started.

Before you begin...

For the purposes of this post, ensure that your API level and Target SDK are set to at least 23. Additionally, ensure that, for backwards compatibility, you are using the V4 support library to verify and request permissions. If you don’t have it already, add it to your gradle file:

 com.android.support:support-v4:23.0.1 

You’ll also need to declare Permissions in your AndroidManifest.xml file. There’s no change here. Whatever permissions your app has always needed should be declared in your AndroidManifest.xml file with the uses-permission tag. Here’s an example:

 <uses-permission android_name="android.permission.ACCESS_FINE_LOCATION"/> 

Documentation on maps and location, including a walkthrough on connecting may be found here.

Step 1. Manage Connections to the GoogleApiClient

Make sure that you are handling connection failures on GoogleApiClient correctly, and that you are using the proper resolution process as outlined here. Note that if Google Play services itself is missing permissions, the user flow to fix them will be handled for you automatically if you follow this methodology.

Here’s an example:

 @Override public void onConnectionFailed(ConnectionResult result) { if (mResolvingError) { // Already attempting to resolve an error. return; } else if (result.hasResolution()) { try { mResolvingError = true; result.startResolutionForResult(this, REQUEST_RESOLVE_ERROR); } catch (SendIntentException e) { // There was an error with the resolution intent. Try again. mGoogleApiClient.connect(); } } else { // Show dialog using GooglePlayServicesUtil.getErrorDialog() showErrorDialog(result.getErrorCode()); mResolvingError = true; } } 

Step 2. Verify Permissions before calling APIs

It’s easy to assume that once you can connect, and you’ve declared the required permissions for APIs that you want to use in your AndroidManifest.xml file, that future calls will be fine. However, it is vital to ensure that you have the required permission before calling an API or connecting to the GoogleApiClient. This can be done using the checkSelfPermission method of ActivityCompat, Fragment or ContextCompat.

If the call returns false, i.e. the permissions aren’t granted, you’ll use requestPermissions to request them. The response to this will be returned in a callback which you will see in the next step.

Here’s an example:

 private static final int REQUEST_CODE_LOCATION = 2; if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) { // Request missing location permission. ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_CODE_LOCATION); } else { // Location permission has been granted, continue as usual. Location myLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient); } 

Step 3. Implement the request permission callback.

In step 2, if the permission wasn’t granted by the user, the requestPermissions method was called to ask the user to grant them. The response from the user is captured in the onRequestPermissionsResult callback. You need to implement this, and always check the return values because the request could be denied or cancelled. Note that you might need to request multiple permissions here -- this sample just checks for a single permission -- you may need to check for more.

 public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { if (requestCode == REQUEST_CODE_LOCATION) { if(grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { // success! Location myLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient); } else { // Permission was denied or request was cancelled } } 

Step 4. Show permission rationale

If the user has previously denied the permission request, your app should display an additional explanation before requesting the permission again. Indeed, if the permissions are non trivial for the core features of the app, and the user is confused as to why they are needed, it would be recommended to guide them.

In this case, before the call to requestPermissions (step 2, above), you should call shouldShowRequestPermissionRationale, and if it returns true, you should create some UI to display additional context for the permission.

As such your code from Step 2 might look like this:

 private static final int REQUEST_CODE_LOCATION = 2; if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) { // Check Permissions Now if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)) { // Display UI and wait for user interaction } else { ActivityCompat.requestPermissions( this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_CODE_LOCATION); } } else { // permission has been granted, continue as usual Location myLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient); } 

Note that in this case your user may still deny the permissions, in which case you will need to craft your app so as not to be in a situation where a denied permission affects parts of the app where it shouldn’t. Refer to the best practices section on the Android developer’s site for more details and guidance.

If you’ve built any applications that use Google Play services, I’d recommend that you download the Google Play services 8.1 SDK, and rebuild your applications using it, testing against the most recent versions of Android 6.0, which you can download from the Android Developers site.

Useful resources:

Get started with building for Android 6.0

Android Permissions design guidelines

Google IO 2015 Session on Android M Permissions

Samples for Google Play services 8.1 with coding best practices


Available link for download

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