C# 使用Xamarin Forms-Android 8.1以编程方式打开APK

我正在尝试从Xamarin.Forms应用程序安装APK。 我使用FileProvider在Android实现中创建了DependencyService，代码如下：

Java.IO.File file = new Java.IO.File(updtFile);
var realUri = Android.Support.V4.Content.FileProvider.GetUriForFile(MainActivity.Instance, MainActivity.Instance.PackageName + ".provider", file);
Intent install = new Intent(Intent.ActionInstallPackage);
install.AddFlags(ActivityFlags.GrantReadUriPermission);
install.AddFlags(ActivityFlags.GrantWriteUriPermission);
install.AddFlags(ActivityFlags.GrantPersistableUriPermission);
install.SetDataAndType(realUri, "application/vnd.android.package-archive");
MainActivity.Instance.StartActivity(install);

它与安卓7完美配合，如期打开软件包管理器。 它对Android 8.1完全没有任何作用，甚至没有抛出异常。我已启用应用程序的所有权限，如果我尝试使用文件资源管理器打开APK，它将正常工作

这是我的舱单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0.1.0" package="..." android:installLocation="auto">
    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28" />
    <application android:label="..." android:icon="@drawable/icon">
        <provider android:name="android.support.v4.content.FileProvider" android:authorities="${applicationId}.provider" android:exported="false" android:grantUriPermissions="true">
            <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/provider_paths" />
        </provider>
    </application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.FLASHLIGHT" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.INSTALL_PACKAGES" />
</manifest>

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

这是provider_path.xml

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
  <external-path name="external_files" path="." />
</paths>

我错过什么了吗

---

谢谢。

找到了！我在清单中缺少此权限：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0.1.0" package="..." android:installLocation="auto">
    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28" />
    <application android:label="..." android:icon="@drawable/icon">
        <provider android:name="android.support.v4.content.FileProvider" android:authorities="${applicationId}.provider" android:exported="false" android:grantUriPermissions="true">
            <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/provider_paths" />
        </provider>
    </application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.FLASHLIGHT" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.INSTALL_PACKAGES" />
</manifest>

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

---

找到了！我在清单中缺少此权限：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0.1.0" package="..." android:installLocation="auto">
    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28" />
    <application android:label="..." android:icon="@drawable/icon">
        <provider android:name="android.support.v4.content.FileProvider" android:authorities="${applicationId}.provider" android:exported="false" android:grantUriPermissions="true">
            <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/provider_paths" />
        </provider>
    </application>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.FLASHLIGHT" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.INSTALL_PACKAGES" />
</manifest>

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