在 Android、Xamarin.forms 的整个应用程序中保持沉浸式模式

Question

我想在 Android 上使用 Xamarin.forms 在整个应用程序中保持沉浸式模式。我读过一些博客和帖子。 This one works but only until I press an input text box or I scroll over the screen. I want to avoid this. 讨论我的担忧，但我不明白解决方案。也许它已经过时了。我的 android 设备是 7.1，这是我在 .Android MainActivity、void OnCreate、void OnCreate:

上的代码

public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity{
    protected override void OnCreate(Bundle savedInstanceState){
        Xamarin.Essentials.Platform.Init(this, savedInstanceState);
        global::Xamarin.Forms.Forms.Init(this, savedInstanceState);

        TabLayoutResource = Resource.Layout.Tabbar;
        ToolbarResource = Resource.Layout.Toolbar;
        base.OnCreate(savedInstanceState);
        LoadApplication(new App());

        ImmersiveMode();
    }

    public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults){
        Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

        base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    public void ImmersiveMode() {
        int uiOptions = (int)(Forms.Context as Activity).Window.DecorView.SystemUiVisibility;
        uiOptions |= (int)SystemUiFlags.Fullscreen;
        uiOptions |= (int)SystemUiFlags.HideNavigation;
        uiOptions |= (int)SystemUiFlags.ImmersiveSticky;
        (Forms.Context as Activity).Window.DecorView.SystemUiVisibility = (StatusBarVisibility)uiOptions;
    }
}

我该如何解决这个问题？你能具体说明我应该把新代码放在哪里吗？我是 Xamarin.Forms 的新手，这对我来说看起来很棘手。谢谢

编辑： 这段代码：

this.Window.AddFlags(WindowManagerFlags.Fullscreen); 在 .Android MainActivity 上隐藏 Android 栏，其中包含 wifi 信号、时间、蓝牙等

是否有像那样的一行来隐藏这个 android 按钮？

Answer 1

Window.DecorView.SystemUiVisibility 自 Android R (11) 起已弃用。在这个 API 版本中有一种新的方法可以做到这一点。

下面是我在我的一个应用程序中使用的代码。我不得不重写 MainActivity class.

中的一堆方法

using System;

using Android.App;
using Android.Content.PM;
using Android.Runtime;
using Android.OS;
using Android.Views;

namespace SampleApp.Droid
{
    [Activity(Label = "SampleApp", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize )]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            LoadApplication(new App());
            SetFullscreenFlags();
        }

        protected override void OnResume()
        {
            base.OnResume();
            SetFullscreenFlags();
        }

        public override void OnWindowFocusChanged(bool hasFocus)
        {
            base.OnWindowFocusChanged(hasFocus);
            SetFullscreenFlags();
        }

        protected void SetFullscreenFlags()
        {
            var attrs = Window.Attributes;
            attrs.Flags |= WindowManagerFlags.Fullscreen;
            Window.Attributes = attrs;

            // BuildVersionCodes has a wrong value for Android R (1000 instead of 30)
            // https://github.com/xamarin/xamarin-android/issues/5723
            // if (Build.VERSION.SdkInt >= BuildVersionCodes.R)
            if ((int)Build.VERSION.SdkInt >= 30)
            {
                Window.SetDecorFitsSystemWindows(false);

                if (Window.InsetsController != null)
                {
                    Window.InsetsController.Hide(WindowInsets.Type.NavigationBars());
                    Window.InsetsController.Hide(WindowInsets.Type.StatusBars());
                    Window.InsetsController.Hide(WindowInsets.Type.SystemBars());
                    Window.InsetsController.Show(WindowInsets.Type.Ime());
                }
            }
            else
            {
                var uiOptions = (int)Window.DecorView.SystemUiVisibility;
                var newUiOptions = (int)uiOptions;

                newUiOptions |=
                    (int)SystemUiFlags.LayoutStable |
                    (int)SystemUiFlags.LayoutHideNavigation |
                    (int)SystemUiFlags.LayoutFullscreen |
                    (int)SystemUiFlags.HideNavigation |
                    (int)SystemUiFlags.Fullscreen |
                    (int)SystemUiFlags.ImmersiveSticky;

                Window.DecorView.SystemUiVisibility = (StatusBarVisibility)newUiOptions;
            }
        }

        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
        {
            Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        }

    }
}

之前，我也实现了View.IOnSystemUiVisibilityChangeListener接口。但它也已弃用，将在以后的版本中删除：

public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity, View.IOnSystemUiVisibilityChangeListener
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        // omitted code

        Window.DecorView.SetOnSystemUiVisibilityChangeListener(this);
    }

    public void OnSystemUiVisibilityChange([GeneratedEnum] StatusBarVisibility visibility)
    {
        SetFullscreenFlags();
    }
}

编辑：

如果您想在用户将某些输入控件聚焦在您的屏幕上后保持沉浸式模式，您可以实现 ViewTreeObserver.IOnGlobalFocusChangeListener 接口。这是我的做法：

public class MainActivity : 
    global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity, 
    ViewTreeObserver.IOnGlobalFocusChangeListener
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        // ommited code
    }

    public override void SetContentView(View view)
    {
        base.SetContentView(view);

        if (view?.ViewTreeObserver != null)
            view.ViewTreeObserver.AddOnGlobalFocusChangeListener(this);
    }

    public override void SetContentView(View view, ViewGroup.LayoutParams @params)
    {
        base.SetContentView(view, @params);

        if (view?.ViewTreeObserver != null)
            view.ViewTreeObserver.AddOnGlobalFocusChangeListener(this);
    }

    public void OnGlobalFocusChanged(View oldFocus, View newFocus)
    {
        SetFullscreenFlags();
    }
}

在 Android、Xamarin.forms 的整个应用程序中保持沉浸式模式

Keep immersive mode all over the app on Android, Xamarin.forms

c#

android

xamarin

xamarin.forms

android-immersive

编辑：