Code to get JSON from server causes crash when run in android version 9

Question

The following piece of code runs successfully if the android version is 6 or 7 but crashes for android version 9

public class TestConnectionToServer extends AsyncTask<String, Void, String>{

String IPConnection ="http://************";

public String doInBackground(String... IntegerParam) {
    try {               
        URL url = new URL(IPConnection+"TestConnectionToServer");
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

        try {
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));    
            StringBuilder stringBuilder = new StringBuilder();
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                stringBuilder.append(line);
            }

            bufferedReader.close();         
            return stringBuilder.toString();                
        }                   
        finally {
            urlConnection.disconnect();
        }
    }       
    catch(Exception e) {        
        Log.e("ERROR", e.getMessage(), e);
        return e.getMessage();     
    }   
}

Answer 1

One network related change with Android 9 is that it's no longer easy to use http instead of https, see Protecting users with TLS by default in Android P.

Most likely you can just switch to https.

If you want to/ have to stay with http, you have to change your app's network security config.

• Create a resource directory named xml in the main/res folder
• Create an XML resource file mynetworksecurityconfig.xml in this directory
• To allow insecure cleartext connections to a specific domain, you can declare the network security configuration as follows:

mynetworksecurityconfig.xml

<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">insecure.example.com</domain>
    </domain-config>
</network-security-config>

• Finally, add a link to the config file in the app's Manifest.xml by setting the android:networkSecurityConfig attribute in the application tag

 

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.example.mynetworksecurityconfigtest">

    <application android:networkSecurityConfig="@xml/mynetworksecurityconfig"
                ... >
        ...
    </application>
</manifest>

See the training unit on Network security configuration for more information.