android-M_permissions.slide

Android M permission

Louis Chan
Developer, Oursky
louischan@oursky.com

* Permission in Android M

Permission are now classified into 2 types.

- Normal: same as before, need not special handling
- Dangerous: must check before use

[[http://developer.android.com/guide/topics/security/permissions.html#perm-groups]]

* Permission group

Permission are granted as group.

e.g. If your app are granted [[http://developer.android.com/reference/android/Manifest.permission.html#WRITE_EXTERNAL_STORAGE][WRITE_EXTERNAL_STORAGE]] permission, it is automatically granted [[http://developer.android.com/reference/android/Manifest.permission.html#READ_EXTERNAL_STORAGE][READ_EXTERNAL_STORAGE]].

* int ContextCompat.checkSelfPermission(Context context, String permission)
Return `PackageManager.PERMISSION_DENIED` or `PackageManager.PERMISSION_GRANTED`.

* boolean ActivityCompat.shouldShowRequestPermissionRationale(Activity activity, String permission)

Return `false` if it is the first time asking for permission.

Return `true` if the request was denied *AND* "never ask again" was *NOT* checked.

Return `false` if the request was deined *AND* "never ask again" was checked.

* void ActivityCompat.requestPermissions(Activity activity, String[] permissions)

`activity` must implement `ActivityCompat.OnRequestPermissionResultCallback`.

Display a non-customizable dialog if "never ask again" was not checked.

Invoke the callback instantly otherwise.

* Example flow

  // the snippet may reside in a OnClickListener

  if (ContextCompat.checkSelfPermission(context, permission)) {
    // process as normal
  } else {
    if (ActivityCompat.shouldShowRequestPermissionRationale(activity, permission)) {
      // This implies the user has denied in the past
      // the app should explain why the app need the permission in its own way
    } else {
      ActivityCompat.requestPermissions(activity, new String[]{permission});
    }
  }

* Example flow (cont.)

  // the implementation of ActivityCompat.OnRequestPermissionResultCallback

  public void onRequestPermissionResult(int requestCode, String[] permissions, int[] grantResults) {
    super.onRequestPermissionResult(requestCode, permissions, grantResults);
    
    if (requestCode != MY_REQUEST_CODE) {
      return;
    }
    
    if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
      // process as normal
    } else if (ActivityCompat.shouldShowRequestPermissionRationale(activity, permission)) {
      // This implies request was deined but never ask again was not checked
    } else {
      // This implies the dialog actually did not show and this method was invoke instantly
      // If the permission is essential to the app, the app should tell the user
      // the app will not function properly without the permission
    }
  }

* Redirect to the app details in settings

  Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
  Uri uri = Uri.fromParts("package", YOUR_APP_PACKAGE_NAME, null);
  intent.setData(uri);
  startActitity(intent);

The above intent will open up the app details in settings but the user have to manually click to enter the permission page.