// Ví dụ ViewModel cho màn hình sửa một học phần.
// Cần AndroidX Lifecycle ViewModel SavedState trong dự án Android.
import androidx.lifecycle.LiveData;
import androidx.lifecycle.SavedStateHandle;
import androidx.lifecycle.ViewModel;

public final class DraftViewModel extends ViewModel {
    private static final String COURSE_ID = "courseId";
    private static final String QUERY = "query";
    private final SavedStateHandle state;

    public DraftViewModel(SavedStateHandle state) {
        this.state = state;
    }

    public void selectCourse(String id) {
        state.set(COURSE_ID, id);
    }

    public LiveData<String> courseId() {
        return state.getLiveData(COURSE_ID);
    }

    public void setQuery(String query) {
        state.set(QUERY, query);
    }

    public LiveData<String> query() {
        return state.getLiveData(QUERY, "");
    }
}