What's the best way to check for permissions at runtime using MVP architecture?

Question

I\'m developing an android app in which I have to ask for permissions at runtime. I\'m wondering about the best way to implement that using Model-View-Presenter architecture.

Answer 1

Permissions requests and status are View(Fragment or Activity) responsibility due to depend of the user actions to make a request or grant permissions. I manage permissions with MVP as follows(Read external storage example):

My Contract

interface View {
    ...
    void requestReadPermission();
    boolean areReadPermissionGranted();
    void showPermissionError();
    void hidePermissionError();
    ...
}

interface Presenter {
    ...
    void setReadPermissions(boolean grantedPermissions);
    ...
}

interface Model {
    ...
}

My view implementation. (Fragment in this case but it can be Activity or whatever, the Presenter will only expect the response).

public class MyView extends Fragment implements Contract.View {

...
Contract.Presenter presenter;

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    boolean grantedPermissions =  (grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED);
    presenter.setReadPermissions(grantedPermissions);
}



@Override
public void showPermissionError() {
    // Show not permission message
}

@Override
public void hidePermissionError() {
    // Hide not permission message
}

@Override
public void requestReadPermission() {
    this.requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
}
@Override
public boolean areReadPermissionGranted() {
    return ContextCompat.checkSelfPermission(getContext(), Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
}
...

And the Presenter implementation

public class MyPresenter implements Contract.Presenter {

...
Contract.View view;

public void doSomethingThatRequiresPermissions() {

    ...
        if ( !view.areReadPermissionGranted() ) {
            view.requestReadPermission();
            view.showPermissionError();
        } else {
            view.hidePermissionError();
            doSomethingWithPermissionsGranted();
        }
    ...
}

@Override
public void setReadPermissions(boolean grantedPermissions) {
    if( grantedPermissions ){
        view.hidePermissionError();
        doSomethingThatRequiresPermissions();

    } else {
        view.showPermissionError();
    }
}

public void doSomethingWithPermissionsGranted(){
    ...
}

Then you can make unit test like

Contract.View mockedView;
@Test
public void requestAlbumListWithoutPermissions() {
    when(mockedView.areReadPermissionGranted()).thenReturn(false);
    presenter.doSomethingWithPermissionsGranted();
    verify(mockedView).showPermissionError();
    verify(mockedView).requestReadPermission();
}