title: Android studio cannot resolve method 'add(int,com.*...*.LoginFragment)
body: <p>Im trying to use Fragments on my app, but for some reason i get this error "cannot resolve method 'add(int,com.<em>...</em>.LoginFragment). i dont know what to do. i havce tried to import android.app.v4.... but its still giving me that error. </p>
  
  <p><strong>this is the code</strong></p>
  
  <pre><code>    import android.app.Activity;
      import android.app.Fragment;
      import android.app.FragmentManager
      import android.app.FragmentTransaction; 
      import android.content.Intent;
      import android.os.Bundle;
      import android.util.Log
      import android.view.View;
      import android.widget.Button;
      import android.widget.EditText;
      import com.google.android.gms.common.ConnectionResult;    
      import com.google.android.gms.common.GoogleApiAvailability; 
  
  
        public class TemplateLogReg extends Activity implements Connector {
        private static final int PLAY_SERVICES_RESOLUTION_REQUEST = 9000;
        private static final String TAG = "Login";
        LoginFragment lg;
        EditText userTxt, passTxt;
        Button ret, reg, loginBtn, btnNewUser;
        private RegisterUser regUser;
        EditText phone, email, password;
  
  
  
       @Override
         protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
           setContentView(R.layout.template_log_reg);
          if (checkPlayServices()) {
            // Start IntentService to register this application with GCM.
           Intent intent = new Intent(this, RegistrationIntentService.class);
            startService(intent);
        }
  
  
        reg = (Button) findViewById(R.id.regButton);
         phone = (EditText) findViewById(R.id.phoneEt);
         email = (EditText) findViewById(R.id.emailEt);
         password = (EditText) findViewById(R.id.passwordEt);
        ret = (Button) findViewById(R.id.ret);
        btnNewUser = (Button) findViewById(R.id.btnNewUser);
        userTxt = (EditText) findViewById(R.id.etPhone);
        passTxt = (EditText) findViewById(R.id.etPassword);
        loginBtn = (Button) findViewById(R.id.loginBtn);
        lg = new LoginFragment();
        lg.setInterface(this);
  
        /** this code show us the login page. 5 lines **/
         FragmentManager fm = getFragmentManager();
         FragmentTransaction ft = fm.beginTransaction();
         lg = new LoginFragment();
         lg.setInterface(this);
         ft.add(R.id.fragment_container, lg); // this line error
         ft.commit();
  </code></pre>