RxMenuItemCompat.java

package com.jakewharton.rxbinding2.support.v4.view;

import android.support.annotation.CheckResult;
import android.support.annotation.NonNull;
import android.view.MenuItem;
import com.jakewharton.rxbinding2.internal.Functions;
import com.jakewharton.rxbinding2.view.MenuItemActionViewEvent;
import io.reactivex.Observable;
import io.reactivex.functions.Predicate;

import static com.jakewharton.rxbinding2.internal.Preconditions.checkNotNull;

/**
 * Static factory methods for creating {@linkplain Observable observables}
 * for {@link android.support.v4.view.MenuItemCompat}.
 */
public final class RxMenuItemCompat {

  /**
   * Create an observable of action view events for {@code menuItem}.
   * <p>
   * <em>Warning:</em> The created observable keeps a strong reference to {@code menuItem}.
   * Unsubscribe to free this reference.
   * <p>
   * <em>Warning:</em> The created observable uses {@link MenuItem#setOnActionExpandListener} to
   * observe action view events. Only one observable can be used for a menu item at a time.
   */
  @CheckResult @NonNull public static Observable<MenuItemActionViewEvent> actionViewEvents(
      @NonNull MenuItem menuItem) {
    checkNotNull(menuItem, "menuItem == null");
    return new MenuItemActionViewEventObservable(menuItem, Functions.PREDICATE_ALWAYS_TRUE);
  }

  /**
   * Create an observable of action view events for {@code menuItem}.
   * <p>
   * <em>Warning:</em> The created observable keeps a strong reference to {@code menuItem}.
   * Unsubscribe to free this reference.
   * <p>
   * <em>Warning:</em> The created observable uses {@link MenuItem#setOnActionExpandListener} to
   * observe action view events. Only one observable can be used for a menu item at a time.
   *
   * @param handled Function invoked with each value to determine the return value of the
   * underlying {@link MenuItem.OnActionExpandListener}.
   */
  @CheckResult @NonNull public static Observable<MenuItemActionViewEvent> actionViewEvents(
      @NonNull MenuItem menuItem, @NonNull Predicate<? super MenuItemActionViewEvent> handled) {
    checkNotNull(menuItem, "menuItem == null");
    checkNotNull(handled, "handled == null");
    return new MenuItemActionViewEventObservable(menuItem, handled);
  }

  private RxMenuItemCompat() {
    throw new AssertionError("No instances.");
  }
}