Question

我需要在我的应用程序的主要活动中添加一个抽屉。我看过一些教程，并添加了所有必要的代码，抽屉可以打开和关闭。但是，我无法选择任何项目。当我单击其中的任何一个时，抽屉都将关闭，并且本应执行的代码永远不会运行。

这些是我的MainActivity.cs的第一行：

public class MainActivity : AppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            SetContentView(Resource.Layout.activity_main);

            Android.Support.V7.Widget.Toolbar toolbar = FindViewById<Android.Support.V7.Widget.Toolbar>(Resource.Id.toolbar);
            DrawerLayout drawer = FindViewById<DrawerLayout>(Resource.Id.drawer_layout);
            ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar, Resource.String.navigation_drawer_open, Resource.String.navigation_drawer_close);
            drawer.AddDrawerListener(toggle);
            toggle.SyncState();

            NavigationView navigationView = FindViewById<NavigationView>(Resource.Id.nav_view);
            navigationView.NavigationItemSelected += NavigationView_NavigationViewSelected;

以及NavigationView_NavigationViewSelected事件：

void NavigationView_NavigationViewSelected(object sender, NavigationView.NavigationItemSelectedEventArgs e)
        {
            switch (e.MenuItem.ItemId)
            {
                case (Resource.Id.nav_search):
                    Android.Util.Log.WriteLine(Android.Util.LogPriority.Info, "SmartLyrics", "MainActivity.cs: Test for Search button on drawer");
                    break;
                case (Resource.Id.nav_saved):
                    Android.Util.Log.WriteLine(Android.Util.LogPriority.Info, "SmartLyrics", "MainActivity.cs: Test for Saved button on drawer");
                    break;
                case (Resource.Id.nav_settings):
                    Android.Util.Log.WriteLine(Android.Util.LogPriority.Info, "SmartLyrics", "MainActivity.cs: Test for Settings button on drawer");
                    break;
                case (Resource.Id.nav_about):
                    Android.Util.Log.WriteLine(Android.Util.LogPriority.Info, "SmartLyrics", "MainActivity.cs: Test for About button on drawer");
                    break;
            }
        }

当我单击选项时，LogCat在此事件内不显示任何消息。我在这里缺少任何代码吗？

Answer 1

您的MainActivity类未实现NavigationView.OnNavigationItemSelectedListener。

您的MainActivity类必须实现NavigationView.OnNavigationItemSelectedListener

Answer 2

尝试像这样更改您的xaml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:orientation="vertical"
   android:layout_width="match_parent"
   android:layout_height="match_parent">
  <android.support.v7.widget.Toolbar
       android:minWidth="25dp"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:minHeight="?attr/actionBarSize"
       android:id="@+id/toolbar" />
  <android.support.v4.widget.DrawerLayout
       android:id="@+id/drawer_layout"
       android:layout_width="match_parent"
       android:layout_height="match_parent">
    <include
       layout="@layout/content_main"
       android:layout_width="match_parent"
       android:layout_height="match_parent" />

   <android.support.design.widget.NavigationView
       android:id="@+id/nav_view"
       android:layout_width="wrap_content"
       android:layout_height="match_parent"
       android:layout_gravity="start"
       android:fitsSystemWindows="true"
       app:headerLayout="@layout/nav_header_main"
       app:menu="@menu/activity_main_drawer"
    />

   </android.support.v4.widget.DrawerLayout>
</LinearLayout>

NavigationItemSelected未在导航抽屉上调用

2 个答案: