Android: How to grab username info after login and display welcome 'username' in MainActivity

I have done alot of search for this and most of them are not for android.

I am using sharedpref to save the username in session until logout. I would like to display welcome 'username' in the mainactivity.

. For now I would like a sample code on grabbing the 'username' within the mainactivity class thats saved in sharedprefs and display it in textview.

Below is my login class that opens the mainActivity

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);

        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString("username", username);
        editor.commit();

        if(prefs.getString("username", null)!=null)
        {Intent i = new Intent(getApplicationContext(), Customer.class); 
        startActivity(i);}

        etUsername = (EditText)findViewById(R.id.username);
        btnLogin = (Button)findViewById(R.id.login_button);
        btnCancel = (Button)findViewById(R.id.cancel_button);
        lblResult = (TextView)findViewById(R.id.result);

        btnLogin.setOnClickListener(new OnClickListener() {
            //@Override
            public void onClick(View v) {
            // Check Login
            String username = etUsername.getText().toString();


            if(username.equals("1111")){
                lblResult.setText("Login successful.");

               Intent i = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(i);
                            } 
            else if(username.equals("2222")){
                lblResult.setText("Login successful.");

                Intent i = new Intent(getApplicationContext(), MainActivity2.class);
                startActivity(i);

            }
btnCancel.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
               // Close the application
            finish();

                }
            });   }

MainActivity.java

public class MainActivity extends ListActivity
{

    TextView selection;
    CustomerListItem[] items = { 
            new CustomerListItem("Start Trip", StartTripActivity.class), 
            new CustomerListItem("Clock in", ClockinActivity.class), 
            new CustomerListItem("Log Out", LogoutActivity.class)};
    private TextView resultsTxt;

    @Override
    public void onCreate(Bundle icicle)
    {
        super.onCreate(icicle);
        setContentView(R.layout.customer);
        setListAdapter(new ArrayAdapter<CustomerListItem>(
                this, android.R.layout.simple_list_item_1, items));
        selection = (TextView) findViewById(R.id.selection);
showname = (TextView) findViewById(R.id.showname);
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id)
    {
        super.onListItemClick(l, v, position, id);
        final Intent intent = new Intent(this, items[position].getActivity());
        startActivityForResult(intent, position);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent)
    {
        super.onActivityResult(requestCode, resultCode, intent);
        if (resultCode == RESULT_OK)
        {
            // Perform different actions based on from which activity is
            // the application returning:
            switch (requestCode)
            {
                case 0:
                    // TODO: handle the return of the 
                    break;
                case 1:
                    // TODO: handle the return of the                     
break;
                case 2:
                    // TODO: handle the return of the                    
break;
                default:
                    break;
            }
        }
        else if (resultCode == RESULT_CANCELED)
        {
            resultsTxt.setText("Canceled");
        }
    }
}

Try...

In your login Activity:

SharedPreferences prefs = getSharedPreferences("MyApp", MODE_PRIVATE);
prefs.edit().putString("username", username).commit();
Intent i = new Intent(this, MainActivity.class); 
startActivity(i);

In your main activity...

public class MainActivity extends Activity {

    private String username = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // setContentView(...) here

        SharedPreferences prefs = getSharedPreferences("MyApp", MODE_PRIVATE);
        username = prefs.getString("username", "UNKNOWN");

        ...

    }
}

First, you should pass the username as an extra so the next activity can grab it. Put this in your login activity:

String username = prefs.getString("username");

Intent i = new Intent(this, MainActivity.class);
// this is where you should pass the username
i.putExtra("username", username);
startActivity(i);

After that, put this in your MainActivity, probably in the onCreate method:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mainview);

    Bundle extras = getIntent().getExtras();

    if (extras.containsKey("username")) {
        String username = extras.getString("username");

        // put whatever code you want here to show the username

    }
}

Hope it answers your question.