How to check if permission is granted by user at runtime on Android?

Question

I have created a simple android activity that acts as a dial. It has an edit text for the phone number and a call button Here is the code : (android 6.0 marshmallow)

public class Main2Activity extends AppCompatActivity {
EditText num;
Button call;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    num = (EditText) findViewById(R.id.num);
    call = (Button) findViewById(R.id.call);
    call.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            try {
                // request permission if not granted
                if (ActivityCompat.checkSelfPermission(Main2Activity.this, Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(Main2Activity.this, new String[]{Manifest.permission.CALL_PHONE}, 123);
                    // i suppose that the user has granted the permission
                    Intent in = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + num.getText().toString()));
                    startActivity(in);
                 // if the permission is granted then ok
                } else {
                    Intent in = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + num.getText().toString()));
                    startActivity(in);
                }
            }
            // catch the exception if I try to make a call and the permission is not granted
            catch (Exception e){
            }
        }
    });
}

}

When I run my app, I have these issues

• If I click on the call button and grant permission, the intent is not called until I click again

• I don't know how to check if the permission was granted or not

Answer 1

Use onRequestPermissionResult, It handles the action if user press ALLOW and DENY, Just call the intent in the condition "if the user presses allow":

@Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case 123: {
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                   //If user presses allow
                   Toast.makeText(Main2Activity.this, "Permission granted!", Toast.LENGTH_SHORT).show();
                   Intent in = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + num.getText().toString()));
                startActivity(in);
                } else {
                   //If user presses deny
                   Toast.makeText(Main2Activity.this, "Permission denied", Toast.LENGTH_SHORT).show();
                }
                break;
            }
        }
    }

Hope this helps.

Answer 2

if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) is terrible logic for checking permission result, i don't know why Google implemented such a terrible code.

It's a mess especially when you check multiple permissions. Let say you ask for CAMERA, ACCESS_FINE_LOCATION and ACCESS_NETWORK_STATE.

You need to check for ACCESS_FINE_LOCATION but user only granted CAMERA at first run and you check for grantResults[1] but in second run ACCESS_FINE_LOCATION becomes the permission with index 0. I got so many problems with user not granting all permissions at once.

You should either use

   int size = permissions.length;
    boolean locationPermissionGranted = false;

    for (int i = 0; i < size; i++) {
        if (permissions[i].equals(Manifest.permission.ACCESS_FINE_LOCATION)
                && grantResults[i] == PackageManager.PERMISSION_GRANTED) {
            locationPermissionGranted = true;
        }
    }

Or simpler one

   if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
           // Do something ...
        }

in onPermissionRequestResult method.