based on https://github.com/bishwassagar/Android-Webview-App
AppMarket for Android. the app installing apps via shell comands.(need root).
in line 85. mWebView.loadUrl("https://yourdomain.com"); //Replace The Link Here
The link to download an app through the market should look like this: yourdomain.com/yourapp.apk So that the market will recognize the name of the downloaded file and you can install it.