Requery 3 - JOIN והוספות

/** Creates one plain single-line dialog input. */
private EditText field(String hint) {
    EditText field = new EditText(this);
    field.setHint(hint);
    field.setSingleLine();
    return field;
}

/** Creates a small label for a dialog field. */
private TextView label(String text) {
    TextView label = new TextView(this);
    label.setText(text);
    return label;
}

/** Creates a Spinner that displays the supplied strings. */
private Spinner spinner(List<String> values) {
    Spinner spinner = new Spinner(this);
    spinner.setAdapter(new ArrayAdapter<>(this,
            android.R.layout.simple_spinner_dropdown_item, values));
    return spinner;
}

/** Stacks dialog controls vertically with density-independent horizontal padding. */
private LinearLayout form(View... fields) {
    LinearLayout form = new LinearLayout(this);
    form.setOrientation(LinearLayout.VERTICAL);
    int padding = (int) (24 * getResources().getDisplayMetrics().density);
    form.setPadding(padding, 0, padding, 0);
    for (View field : fields) form.addView(field);
    return form;
}

/** Shows brief feedback without adding another persistent view to the screen. */
private void toast(String message) {
    Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}

/** Shows a one-field dialog and inserts a Student when its name is non-empty. */
private void showAddStudent() {
    EditText name = field("Name");
    new AlertDialog.Builder(this)
            .setTitle("Add Student")
            .setView(form(name))
            .setNegativeButton("Cancel", null)
            .setPositiveButton("Add", (dialog, which) -> {
                String value = name.getText().toString().trim();
                if (value.isEmpty()) {
                    toast("Enter a student name");
                } else {
                    Database.addStudent(data, value);
                    toast("Student added");
                }
            })
            .show();
}

/** Shows a two-field dialog and inserts a Movie when both values are non-empty. */
private void showAddMovie() {
    EditText title = field("Title");
    EditText genre = field("Genre");
    new AlertDialog.Builder(this)
            .setTitle("Add Movie")
            .setView(form(title, genre))
            .setNegativeButton("Cancel", null)
            .setPositiveButton("Add", (dialog, which) -> {
                String movieTitle = title.getText().toString().trim();
                String movieGenre = genre.getText().toString().trim();
                if (movieTitle.isEmpty() || movieGenre.isEmpty()) {
                    toast("Enter a title and genre");
                } else {
                    Database.addMovie(data, movieTitle, movieGenre);
                    toast("Movie added");
                }
            })
            .show();
}

/** Returns Student names in the same order as their objects. */
private List<String> namesOf(List<Student> students) {
    List<String> names = new ArrayList<>();
    for (Student student : students) names.add(student.getName());
    return names;
}

/** Returns Movie titles in the same order as their objects. */
private List<String> titlesOf(List<Movie> movies) {
    List<String> titles = new ArrayList<>();
    for (Movie movie : movies) titles.add(movie.getTitle());
    return titles;
}

/** Selects Student and Movie choices, then inserts one rated relationship. */
private void showAddWatching() {
    List<Student> students;
    List<Movie> movies;
    try (Result<Student> rows = data.select(Student.class)
            .orderBy(StudentEntity.NAME).get()) {
        students = rows.toList();
    }
    try (Result<Movie> rows = data.select(Movie.class)
            .orderBy(MovieEntity.TITLE).get()) {
        movies = rows.toList();
    }

    Spinner student = spinner(namesOf(students));
    Spinner movie = spinner(titlesOf(movies));
    EditText rating = field("Rating (1-10)");
    rating.setInputType(InputType.TYPE_CLASS_NUMBER);

    new AlertDialog.Builder(this)
            .setTitle("Add Watching")
            .setView(form(label("Student"), student, label("Movie"), movie, rating))
            .setNegativeButton("Cancel", null)
            .setPositiveButton("Add", (dialog, which) -> {
                int score;
                try {
                    score = Integer.parseInt(rating.getText().toString());
                } catch (NumberFormatException e) {
                    toast("Enter a rating from 1 to 10");
                    return;
                }
                if (score < 1 || score > 10) {
                    toast("Enter a rating from 1 to 10");
                    return;
                }
                try {
                    Database.addWatching(data,
                            students.get(student.getSelectedItemPosition()),
                            movies.get(movie.getSelectedItemPosition()), score);
                    showWatchings();
                    toast("Watching added");
                } catch (PersistenceException e) {
                    toast("That student already watched that movie");
                }
            })
            .show();
}