How can I send data to WebServer in Android?

Question

I'm trying to send data in Android Studio. I'm making a login function. So I need to send data to the Webserver. I already made a Webserver, but I can't because of this error:

Caused by: android.os.NetworkOnMainThreadException

I think that error is pointed at this line:

InputStream is = conn.getInputStream();

I've been struggling for 3 days. Please help.

    public class MainActivity extends AppCompatActivity {
        EditText id;
        EditText pass;
        String custid;
        String password;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        id=(EditText)findViewById(R.id.idtext);
        pass=(EditText)findViewById(R.id.passtext);

    }

    public void ButtonClick(View view){

        custid=id.getText().toString();
        password=pass.getText().toString();
        Toast.makeText(this, "버튼접근."+custid+password, Toast.LENGTH_SHORT).show();
        Properties prop = new Properties();
        prop.setProperty("custid", custid);
        prop.setProperty("password", password);
        String encodedString = encodeString(prop);

        URL url = null;
        try {
            url = new URL ("http://192.168.56.1:9999/SEBank/customer/login.action" + "?" + encodedString);
            URLConnection conn = url.openConnection();
            conn.setUseCaches(false);
            InputStream is = conn.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            char[] buff = new char[512];
            int len = -1;

            while( (len = br.read(buff)) != -1) {
                System.out.print(new String(buff, 0, len));
            }

            br.close();
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }

    }


    public String encodeString(Properties params) {
        StringBuffer sb = new StringBuffer(256);
        Enumeration names = params.propertyNames();

        while (names.hasMoreElements()) {
            String name = (String) names.nextElement();
            String value = params.getProperty(name);
            sb.append(URLEncoder.encode(name) + "=" + URLEncoder.encode(value) );

            if (names.hasMoreElements()) sb.append("&");
        }
        return sb.toString();
    }

}

Answer 1

You can put this on your code

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

but I think the best solution is using AsyncTasks or Volley