首先在AndroidManifest.xml中添加以下行:

<uses-permission android:name="android.permission.INSTALL_PACKAGES"
    tools:ignore="ProtectedPermissions" />

然后使用以下代码安装apk:

File sdCard = Environment.getExternalStorageDirectory();
            String fileStr = sdCard.getAbsolutePath() + "/MyApp";// + "app-release.apk";
            File file = new File(fileStr, "TaghvimShamsi.apk");
            Intent promptInstall = new Intent(Intent.ACTION_VIEW).setDataAndType(Uri.fromFile(file),
                    "application/vnd.android.package-archive");
            startActivity(promptInstall);

好吧，我深入挖掘，并从Android源代码中找到了PackageInstaller应用程序的源代码。

https://github.com/android/platform_packages_apps_packageinstaller

从manifest中我发现它需要许可:

    <uses-permission android:name="android.permission.INSTALL_PACKAGES" />

而实际安装过程发生在确认之后

Intent newIntent = new Intent();
newIntent.putExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO, mPkgInfo.applicationInfo);
newIntent.setData(mPackageURI);
newIntent.setClass(this, InstallAppProgress.class);
String installerPackageName = getIntent().getStringExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME);
if (installerPackageName != null) {
   newIntent.putExtra(Intent.EXTRA_INSTALLER_PACKAGE_NAME, installerPackageName);
}
startActivity(newIntent);

您可以轻松启动市场链接或安装提示:

Intent promptInstall = new Intent(Intent.ACTION_VIEW)
    .setDataAndType(Uri.parse("file:///path/to/your.apk"), 
                    "application/vnd.android.package-archive");
startActivity(promptInstall); 

源

Intent goToMarket = new Intent(Intent.ACTION_VIEW)
    .setData(Uri.parse("market://details?id=com.package.name"));
startActivity(goToMarket);

源

但是，没有用户的明确许可，你不能安装。apks;除非设备和您的程序已经扎根。

试试这个

String filePath = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_FILENAME));
String title = filePath.substring( filePath.lastIndexOf('/')+1, filePath.length() );
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(new File(filePath)), "application/vnd.android.package-archive");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); // without this flag android returned a intent error!
MainActivity.this.startActivity(intent);

大概两个月前，我发现了这个问题。今天回来了，一点头绪也没有。据我所知，我的设置没有任何改变，所以很明显，无论过去的我想到什么，对现在的我来说都不够强大。我终于设法让一些东西重新工作了，所以在这里记录它，以便将来的我和其他可能从另一次尝试中受益的人。

这一尝试代表了原始Android Java安装APK - Session API示例的直接Xamarin c#翻译。它可能需要一些额外的工作，但这至少是一个开始。我让它运行在Android 9设备上，尽管我的项目针对的是Android 11。

InstallApkSessionApi.cs

namespace LauncherDemo.Droid
{
    using System;
    using System.IO;

    using Android.App;
    using Android.Content;
    using Android.Content.PM;
    using Android.OS;
    using Android.Widget;

    [Activity(Label = "InstallApkSessionApi", LaunchMode = LaunchMode.SingleTop)]
    public class InstallApkSessionApi : Activity
    {
        private static readonly string PACKAGE_INSTALLED_ACTION =
                "com.example.android.apis.content.SESSION_API_PACKAGE_INSTALLED";

        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            this.SetContentView(Resource.Layout.install_apk_session_api);

            // Watch for button clicks.
            Button button = this.FindViewById<Button>(Resource.Id.install);
            button.Click += this.Button_Click;
        }

        private void Button_Click(object sender, EventArgs e)
        {
            PackageInstaller.Session session = null;
            try
            {
                PackageInstaller packageInstaller = this.PackageManager.PackageInstaller;
                PackageInstaller.SessionParams @params = new PackageInstaller.SessionParams(
                        PackageInstallMode.FullInstall);
                int sessionId = packageInstaller.CreateSession(@params);
                session = packageInstaller.OpenSession(sessionId);
                this.AddApkToInstallSession("HelloActivity.apk", session);

                // Create an install status receiver.
                Context context = this;
                Intent intent = new Intent(context, typeof(InstallApkSessionApi));
                intent.SetAction(PACKAGE_INSTALLED_ACTION);
                PendingIntent pendingIntent = PendingIntent.GetActivity(context, 0, intent, 0);
                IntentSender statusReceiver = pendingIntent.IntentSender;

                // Commit the session (this will start the installation workflow).
                session.Commit(statusReceiver);
            }
            catch (IOException ex)
            {
                throw new InvalidOperationException("Couldn't install package", ex);
            }
            catch
            {
                if (session != null)
                {
                    session.Abandon();
                }

                throw;
            }
        }

        
        private void AddApkToInstallSession(string assetName, PackageInstaller.Session session)
        {
            // It's recommended to pass the file size to openWrite(). Otherwise installation may fail
            // if the disk is almost full.
            using Stream packageInSession = session.OpenWrite("package", 0, -1);
            using Stream @is = this.Assets.Open(assetName);
            byte[] buffer = new byte[16384];
            int n;
            while ((n = @is.Read(buffer)) > 0)
            {
                packageInSession.Write(buffer, 0, n);
            }
        }

        // Note: this Activity must run in singleTop launchMode for it to be able to receive the intent
        // in onNewIntent().
        protected override void OnNewIntent(Intent intent)
        {
            Bundle extras = intent.Extras;
            if (PACKAGE_INSTALLED_ACTION.Equals(intent.Action))
            {
                PackageInstallStatus status = (PackageInstallStatus)extras.GetInt(PackageInstaller.ExtraStatus);
                string message = extras.GetString(PackageInstaller.ExtraStatusMessage);
                switch (status)
                {
                    case PackageInstallStatus.PendingUserAction:
                        // This test app isn't privileged, so the user has to confirm the install.
                        Intent confirmIntent = (Intent) extras.Get(Intent.ExtraIntent);
                        this.StartActivity(confirmIntent);
                        break;
                    case PackageInstallStatus.Success:
                        Toast.MakeText(this, "Install succeeded!", ToastLength.Short).Show();
                        break;
                    case PackageInstallStatus.Failure:
                    case PackageInstallStatus.FailureAborted:
                    case PackageInstallStatus.FailureBlocked:
                    case PackageInstallStatus.FailureConflict:
                    case PackageInstallStatus.FailureIncompatible:
                    case PackageInstallStatus.FailureInvalid:
                    case PackageInstallStatus.FailureStorage:
                        Toast.MakeText(this, "Install failed! " + status + ", " + message,
                                ToastLength.Short).Show();
                        break;
                    default:
                        Toast.MakeText(this, "Unrecognized status received from installer: " + status,
                                ToastLength.Short).Show();
                        break;
                }
            }
        }
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="com.companyname.launcherdemo" android:installLocation="auto">
    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="30" />
    <application android:label="LauncherDemo.Android" android:theme="@style/MainTheme" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
</manifest>

What I particularly like about this approach is that it does not require any special work in the manifest - no broadcast receivers, file providers, etc. Granted, this takes as its source some APK in the app's assets, whereas a more useful system will probably use some given APK path. I imagine that will introduce a certain level of additional complexity. In addition, I never ran into any issues here (at least as far as I could tell) with the Xamarin GC closing streams before Android was done with them. Nor did I have any issues with the APK not being parsed. I made sure to use a signed APK (the one generated by Visual Studio when deploying to the device worked just fine), and again I did not run into any file access permission issues simply due to using an APK from the app's assets in this example.

这里的一些其他答案提供的一件事是使侧面加载许可授予更加简化的想法。Yabaze Cool的回答提供了如下特色:

Intent unKnownSourceIntent = new Intent(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES). setdata (Uri.parse(字符串。格式(“包:% s activity.getPackageName ()))); 如果(Build.VERSION。SDK_INT >= Build.VERSION_CODES.O) { if (!activity.getPackageManager(). canrequestpackageinstaller ()) { startActivityForResult (unKnownSourceIntent Constant.UNKNOWN_RESOURCE_INTENT_REQUEST_CODE); .．.

当我测试我的翻译时，我卸载了启动器演示程序和它安装的应用程序。没有向canrequestpackageinstalled提供检查，导致我不得不手动按下一个额外的设置按钮，将我带到与上面的ACTION_MANAGE_UNKNOWN_APP_SOURCES意图相同的对话框。因此，添加这个逻辑可以帮助在一定程度上简化用户的安装过程。

只是一个扩展，如果有人需要一个库，那么这可能会有所帮助。感谢Raghav