UpdateNode provides an API for Android to install APK packages from inside another App. You can just define your Update online and integrate the API into your App - that's it. Currently the API is in Beta state, but you can already do some tests yourself. Beside that, UpdateNode offers also displaying messages though the system - pretty useful if you want to tell something important to your users. I am part of the client dev team and am using at least the message functionality for my own Android App.

这里介绍了如何集成API

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。

我只是想分享一个事实，我的apk文件保存到我的应用程序“数据”目录，我需要更改apk文件的权限，使其成为世界可读的，以便允许它以这种方式安装，否则系统会抛出“解析错误:解析包存在问题”;所以使用@Horaceman的解决方案，使:

File file = new File(dir, "App.apk");
file.setReadable(true, false);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
startActivity(intent);

试试这个 -在舱单上填写:

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

编写代码:

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

startActivity(promptInstall);

另一种解决方案不需要硬编码接收应用程序，因此更安全:

Intent intent = new Intent(Intent.ACTION_INSTALL_PACKAGE);
intent.setData( Uri.fromFile(new File(pathToApk)) );
startActivity(intent);

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);