When to request permission at runtime for Android Marshmallow 6.0?

Question

I am testing my app on Marshmallow 6.0 and it's getting force closed for the android.permission.READ_EXTERNAL_STORAGE, even if it is defined in the Manifest already. Somewhere I have read that if I request permission at runtime then it would not force close your application. I have read this android document also, which is for requesting runtime permission.

So, I came to know that we can request a permission like below which is mentioned in the android document.

// Here, thisActivity is the current activity
if (ContextCompat.checkSelfPermission(thisActivity,
                Manifest.permission.READ_CONTACTS)
        != PackageManager.PERMISSION_GRANTED) {

    // Should we show an explanation?
    if (ActivityCompat.shouldShowRequestPermissionRationale(thisActivity,
            Manifest.permission.READ_CONTACTS)) {

        // Show an expanation to the user *asynchronously* -- don't block
        // this thread waiting for the user's response! After the user
        // sees the explanation, try again to request the permission.

    } else {

        // No explanation needed, we can request the permission.

        ActivityCompat.requestPermissions(thisActivity,
                new String[]{Manifest.permission.READ_CONTACTS},
                MY_PERMISSIONS_REQUEST_READ_CONTACTS);

        // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
        // app-defined int constant. The callback method gets the
        // result of the request.
    }
}

The above code has a callback method onRequestPermissionsResult which gets the result.

@Override
public void onRequestPermissionsResult(int requestCode,
        String permissions[], int[] grantResults) {
    switch (requestCode) {

     }
}

My question is where to exactly request the permission to user? Should we use the requesting permission at start of the app or should we do it as when the permission is required?

Answer 1

Do like this

private static final int  REQUEST_ACCESS_FINE_LOCATION = 111;

In your onCreate

boolean hasPermissionLocation = (ContextCompat.checkSelfPermission(getApplicationContext(),
            Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED);
    if (!hasPermissionLocation) {
        ActivityCompat.requestPermissions(ThisActivity.this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                REQUEST_ACCESS_FINE_LOCATION);
    }

then check result

   @Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    switch (requestCode)
    {

        case REQUEST_ACCESS_FINE_LOCATION: {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
            {
                Toast.makeText(ThisActivity.this, "Permission granted.", Toast.LENGTH_SHORT).show();

                //reload my activity with permission granted
                finish();
                startActivity(getIntent());

            } else
            {
                Toast.makeText(ThisActivity.this, "The app was not allowed to get your location. Hence, it cannot function properly. Please consider granting it this permission", Toast.LENGTH_LONG).show();
            }
        }

    }

}

Answer 2

    Android Easy Runtime Permissions with Dexter:
    1. Dexter Permissions Library

    To get started with Dexter, add the dependency in your build.gradle

    dependencies {
        // Dexter runtime permissions
        implementation 'com.karumi:dexter:4.2.0'
    }

    1.1 Requesting Single Permission
    To request a single permission, you can use withPermission() method by passing the required permission. You also need a PermissionListener callback to receive the state of the permission.

    > onPermissionGranted() will be called once the permission is granted.

    > onPermissionDenied() will be called when the permission is denied. Here you can check whether the permission is permanently denied by using response.isPermanentlyDenied() condition.

    The below code requests CAMERA permission.

Dexter.withActivity(this)
                .withPermission(Manifest.permission.CAMERA)
                .withListener(new PermissionListener() {
                    @Override
                    public void onPermissionGranted(PermissionGrantedResponse response) {
                        // permission is granted, open the camera
                    }

                    @Override
                    public void onPermissionDenied(PermissionDeniedResponse response) {
                        // check for permanent denial of permission
                        if (response.isPermanentlyDenied()) {
                            // navigate user to app settings
                        }
                    }

                    @Override
                    public void onPermissionRationaleShouldBeShown(PermissionRequest permission, PermissionToken token) {
                        token.continuePermissionRequest();
                    }
                }).check();

1.2 Requesting Multiple Permissions
To request multiple permissions at the same time, you can use withPermissions() method. Below code requests STORAGE and LOCATION permissions.

Dexter.withActivity(this)
                .withPermissions(
                        Manifest.permission.READ_EXTERNAL_STORAGE,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE,
                        Manifest.permission.ACCESS_FINE_LOCATION)
                .withListener(new MultiplePermissionsListener() {
                    @Override
                    public void onPermissionsChecked(MultiplePermissionsReport report) {
                        // check if all permissions are granted
                        if (report.areAllPermissionsGranted()) {
                            // do you work now
                        }

                        // check for permanent denial of any permission
                        if (report.isAnyPermissionPermanentlyDenied()) {
                            // permission is denied permenantly, navigate user to app settings
                        }
                    }

                    @Override
                    public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
                        token.continuePermissionRequest();
                    }
                })
                .onSameThread()
                .check();