Открыть активность после входа в систему ⇐ Android

[Anonymous]

Я создаю свое первое приложение Android Studio, в которое я частично вошел, но понятия не имею, как открыть новое действие после успешного входа в систему.
Это фоновая задача:
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.os.AsyncTask;
import android.content.Context;
import android.os.AsyncTask;
import android.support.v7.app.AlertDialog;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

public class BackgroundTask extends AsyncTask {

Context ctx;
AlertDialog alertDialog;

BackgroundTask(Context ctx)
{
this.ctx=ctx;
}

protected void onPreExecute() {
super.onPreExecute();

alertDialog=new AlertDialog.Builder(ctx).create();
alertDialog.setTitle("Login Information......");
}

protected String doInBackground(String... params) {
String reg_url = "http://10.0.2.2/webapp/register.php";
String login_url = "http://10.0.2.2/webapp/login.php";
String method = params[0];
if (method.equals("register")) {
String name = params[1];
String user_name = params[2];
String user_pass = params[3];

try {
URL url = new URL(reg_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

httpURLConnection.setRequestMethod("POST");

httpURLConnection.setDoOutput(true);
OutputStream OS = httpURLConnection.getOutputStream();

BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));

String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" + URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(user_name, "UTF-8") + "&" +
URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(user_pass, "UTF-8");

bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
OS.close();
InputStream IS = httpURLConnection.getInputStream();
IS.close();
return "Registration successfully.....";

}
catch (MalformedURLException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}

return null;

}
else if(method.equals("login")){
String login_name = params[1];
String login_pass = params[2];
try {
URL url=new URL(login_url);
HttpURLConnection httpURLConnection= (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
OutputStream outputStream= httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter=new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
String data = URLEncoder.encode("login_name","UTF-8")+"="+URLEncoder.encode(login_name,"UTF-8")+"&"+URLEncoder.encode("login_pass","UTF-8")+"="
+URLEncoder.encode(login_pass,"UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();

InputStream inputStream= httpURLConnection.getInputStream();
BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
String response ="";
String line="";
while ((line=bufferedReader.readLine())!=null)
{
response+=line;
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return response;
}
catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}

protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}

protected void onPostExecute(String result) {
if (result.equals("Registration successfully.....")) {

Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();

} else {
alertDialog.setMessage(result);
alertDialog.show();

}
}
}

Это страница входа:
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
EditText ET_NAME, ET_PASS;
String login_name, login_pass;
Intent intent;
Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

ET_NAME= (EditText)findViewById(R.id.user_name);
ET_PASS= (EditText)findViewById(R.id.user_pass);
button= (Button)findViewById(R.id.button);

button.setOnClickListener(
new View.OnClickListener() {

@Override
public void onClick(View v){
long endTime = System.currentTimeMillis()+20*10;
while(System.currentTimeMillis()< endTime){
synchronized(this){
try{
wait(endTime - System.currentTimeMillis());

}catch (InterruptedException e ){
e.printStackTrace();
}
}
// textView.setText("Button pressed");
}
}
}
);
}

public void userReg (View view)
{
startActivity(new Intent(this,Register.class));
}

public void userLogin (View view) {
login_name=ET_NAME.getText().toString();
login_pass=ET_PASS.getText().toString();
String method ="login";
BackgroundTask backgroundTask=new BackgroundTask(this);
backgroundTask.execute(method,login_name,login_pass);

}

}


Подробнее здесь: https://stackoverflow.com/questions/440 ... ter-log-in