Question

我正在使用xamarin尝试制作Android项目。

我正在尝试学习Android而且我有点陷入困境。我有一个MainActivity，它用作在app start上启动的活动。现在我添加一个启动画面，这意味着另一个活动，但我显然希望这是已启动的活动，并让它在一段时间后启动主要活动。它首先启动了启动活动。好。当它尝试从启动活动启动主活动时，它会关闭。我正在使用xamarin手册中的一个示例，通过一些小的调整来制作这个启动活动，比如让它继承Activity而不是AppCompActivity。

https://developer.xamarin.com/guides/android/user_interface/creating_a_splash_screen/

请注意，MainActivity已经运行了一段时间，现在它只是崩溃或关闭它不是主要的启动器应用程序活动。

我知道我只是缺少一个重要的条目，它可能与清单文件或我的cs文件中缺少声明有关，因为我发现这就是为什么应用程序通常只是悄然关闭。许多清单声明是在运行时在cs文件中生成的，因为它们来自我见过和使用过的样本。这是我的代码。谁能告诉我我失踪了什么？对于长度感到抱歉，但我不确定要包括或不包括。

这是启动活动。

    [Activity(Theme = "@style/MyTheme.Splash", MainLauncher = true, NoHistory = true)]
    public class SplashActivity : Activity
    {
        static readonly string TAG = "X:" + typeof(SplashActivity).Name;

        public override void OnCreate(Bundle savedInstanceState, PersistableBundle persistentState)
        {
            base.OnCreate(savedInstanceState, persistentState);
            Log.Debug(TAG, "SplashActivity.OnCreate");
        }

        // Launches the startup task
        protected override void OnResume()
        {
            base.OnResume();
            Task startupWork = new Task(() => { SimulateStartup(); });
            startupWork.Start();
        }

        // Simulates background work that happens behind the splash screen
     async void SimulateStartup()
        {
            Log.Debug(TAG, "Performing some startup work that takes a bit of time.");
            await Task.Delay(2000); // Simulate a bit of startup work.
            Log.Debug(TAG, "Startup work is finished - starting MainActivity.");
            StartActivity(new Intent(Application.Context, typeof(MainActivity)));
        }
    }

这是我的MainActivity。请注意，它比在此处发布的更多，正如您将在清单文件中看到的权限所反映的那样，但是在此处发布时间过长，并且此活动始终有效，直到现在必须由另一个活动启动。我可以根据要求添加更多内容，但我认为问题出在其他地方

using System;
using System.IO;
using System.Net;
using System.Text;
using Android.Webkit;
using Android.App;
using Android.Content;
using Android.Widget;
using Android.OS;
using Java.Interop;
using Android.Util;
using MyNameSpace.Services;
using Android.Preferences;
using Android.Graphics.Drawables;

namespace MyNameSpace
{
    [Activity(Label = "My Agent", Theme = "@android:style/Theme.NoTitleBar", ConfigurationChanges = Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize | Android.Content.PM.ConfigChanges.KeyboardHidden)]

    public class MainActivity : Activity
    {
        WebView webview = null;
        urlPrefix = "http://example.com/";

        protected override void OnCreate(Bundle bundle)
        {

            base.OnCreate(bundle);
            webview = new WebView(this);
            webview.Settings.JavaScriptEnabled = true;
            webview.Settings.SetGeolocationEnabled(true);
            webview.SetWebViewClient(new MyWebViewClient(this));
            webview.SetWebChromeClient(new MyWebChromeClient(this));
            SetContentView(webview);
            webview.LoadUrl(urlPrefix + "connection.aspx");

            //Set Notification bar but make the activity intent pending on user click of notification msg

            var intent = new Intent(this, typeof(MainActivity));
            intent.AddFlags(ActivityFlags.SingleTop);
            var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.UpdateCurrent);

            Notification.Builder builder = new Notification.Builder(this)
                    .SetContentTitle("My Agent Running")
                    .SetContentText("Show in forground")
                    .SetSmallIcon(Resource.Drawable.hippo72)
                    .SetContentIntent(pendingIntent);

            // Build the notification:

            notification = builder.Build();

            // Get the notification manager:

            notificationManager = GetSystemService(Context.NotificationService) as NotificationManager;

            // Publish the notification:

            notificationManager.Notify(notificationId, notification);

    public class MyWebViewClient : WebViewClient
    {
        private readonly Context _context;
        public MyWebViewClient(Context context)
        {
            _context = context;
        }
        public bool shouldOverrideUrlLoading(WebView view, String url)
        {
            var uri = Android.Net.Uri.Parse(url);
            var intent = new Intent(Intent.ActionView, uri);
            _context.StartActivity(intent);
            return true;
        }
    }

    public class MyWebChromeClient : WebChromeClient
    {
        private readonly Context _context;

        public MyWebChromeClient(Context context)
        {
            _context = context;
        }

        public override void OnGeolocationPermissionsShowPrompt(string origin, GeolocationPermissions.ICallback callback)
        {
        callback.Invoke(origin, true, false);
    }
}

}

我的清单文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.mydomain.myagent" android:versionCode="1" android:versionName="1.0">
<uses-sdk android:minSdkVersion="14" android:targetSdkVersion="23" />
<application android:label="My Agent" android:icon="@drawable/hippo72"></application>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INSTALL_PACKAGES" />
<uses-permission android:name="android.permission.INSTALL_LOCATION_PROVIDER" />
<uses-permission android:name="com.android.launcher.permission.INSTALL_SHORTCUT" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.LOCATION_HARDWARE" />
<uses-permission android:name="android.permission.PERSISTENT_ACTIVITY" />
<uses-permission android:name="com.android.launcher.permission.UNINSTALL_SHORTCUT" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.SEND_SMS" />

Answer 1

在SplashActivity中试用此代码。

使用Finish（）;没有任务和async / await

[Activity(MainLauncher = true, Theme = "@style/MyTheme.Splash", NoHistory = true)]
public class SplashActivity : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        Intent startup = new Intent(this, typeof(MainActivity));
        StartActivity(startup);
        Finish();
    }
}

SplashActivity关闭Android应用程序

1 个答案: