“You need to use a Theme.AppCompat theme (or descendant) with this activity.” Xamarin

问题

I'm adding a floating action button to my app, I have a material design theme and set it into the Android Manifest, I've already set the AppCompatActivity inheritance to the MainActivity but if I run my app I have an exception says " You need to use a Theme.AppCompat theme (or descendant) with this activity."

This is my main activity:

using System;
using Android.App;
using Android.Widget;
using Android.OS;
using Android.Support.Design.Widget;
using Android.Support.V4.View;
using Android.Support.V7.App;
using Android.Views;

namespace M_v1
{
    [Activity(Label = "Muzzillo_v1", MainLauncher = true)]
    public class MainActivity : AppCompatActivity
    {
        Android.Support.V7.Widget.Toolbar toolbar;
        private FloatingActionButton fabMain;
        private View bgFabMenu;
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            TabLayout tabLayout = (TabLayout)FindViewById(Resource.Id.tablayout_navigation);

            ViewPager viewPager = (ViewPager)FindViewById(Resource.Id.pager);
            SetupviewPager(viewPager);

            fabMain = FindViewById<FloatingActionButton>(Resource.Id.fab);
            bgFabMenu = FindViewById<View>(Resource.Id.bg_fab_menu);

            fabMain.Click += FabMain_Click;

            tabLayout.SetupWithViewPager(viewPager);

            toolbar = FindViewById<Android.Support.V7.Widget.Toolbar>(Resource.Id.toolbar);

            toolbar.Title = "App_v1";
        }

        private void FabMain_Click(object sender, EventArgs e)
        {
            throw new NotImplementedException();
        }

        private void SetupviewPager(ViewPager viewPager)
        {
            viewPager.OffscreenPageLimit = 2;

            PageAdapter adapter = new PageAdapter(SupportFragmentManager);
            adapter.AddFragment(new Fragment1(), "One");
            adapter.AddFragment(new Fragment2(), "Two");

            viewPager.Adapter = adapter;
        }

    }
}

And this is my Theme:

<resources>
  <style  name = "AppTheme.Base" parent = "Theme.AppCompat.Light.NoActionBar">
    <item name ="colorPrimary">@color/primary</item>
    <item name ="colorPrimaryDark">@color/primaryDark</item>
    <item name="android:windowBackground">@color/window_background</item>
    <item name="windowActionModeOverlay">true</item>
  </style>

  <style name="AppTheme" parent="AppTheme.Base">
  </style>
</resources>

Android Manifest:

android:theme="@style/AppTheme"

回答1:

You need to use a Theme.AppCompat theme (or descendant) with this activity.

There are two solutions to solve your problem :

Set Activity theme in Application scope in Manifest.xml (all activities)
Or add a Theme attribute in Activity.

1. Theming an Application

Set Activity theme in Application scope in Manifest.xml (all activities) :

<application 
    android:label="@string/app_name" 
    android:icon="@drawable/Icon" 
    android:theme="@style/AppTheme">
</application>

2. Theming an Activity

In Xamarin.Android, it is recommended to add the Activity theme as an attribute. You could read the document Material Theme :

To theme an activity, you add a Theme setting to the [Activity] attribute above your activity declaration and assign Theme to the Material Theme flavor that you want to use. The following example themes an activity with Theme.Material.Light:

For example :

[Activity(Label = "Muzzillo_v1", MainLauncher = true, Theme = "@style/AppTheme")]
public class MainActivity : AppCompatActivity

来源：https://stackoverflow.com/questions/48174193/you-need-to-use-a-theme-appcompat-theme-or-descendant-with-this-activity-xa

标签

xamarin.android

floating-action-button