以编程方式在Android版本24，Nougat中打开下载的apk文件

Question

需要安装由下载管理器下载的apk。安装意味着，显示安装页面。我想在Android 24 API，Nougat中实现。我在res的xml文件夹中创建了provider_path命名文件。并在Android清单中添加了提供程序。每当我尝试传递URI时，它都会显示安装程序崩溃或apk不正常。请帮忙。

我的代码： 提供者路径xml     provider_path.xml

<?xml version="1.0" encoding="utf-8"?>
<paths>
<external-path
    name="external_files"
    path="." />
</paths>

Android Manifest

    <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="$$$$$.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/provider_paths" />
    </provider>

运行安装程序弹出：

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    Intent intent = new Intent(Intent.ACTION_VIEW);
    Uri uri = null;
    if (apkPath.substring(0, 7).matches("file://")) {
        apkPath = apkPath.substring(7);
    }
    uri = FileProvider.getUriForFile(context, context.getPackageName() + ".provider", new File(apkPath));

    List<ResolveInfo> resInfoList = context.getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
    for (ResolveInfo resolveInfo : resInfoList) {
        String packageName = resolveInfo.activityInfo.packageName;
        context.grantUriPermission(packageName, uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION);
    }
    intent.setDataAndType(uri, "application/vnd.android.package-archive");
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(intent);
}