android if-statement doesn't work

public class MainActivity extends Activity {

public static String EXTRA_MESSAGE;



private Intent ceec;
private  EditText cc;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);}






public void sendMessage(View view) 
{
    ceec = new Intent(this, ToActivity.class);

    cc = (EditText) findViewById(R.id.edit_message);


    String message = cc.getText().toString();
    ceec.putExtra(EXTRA_MESSAGE, message);
    startActivity(ceec);

}}

And

public class ToActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);

    Intent intent = getIntent();
    String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

    // Create the text view
    TextView textView = new TextView(this);

    textView.setText(message);
    textView.setTextColor(Color.rgb(5,8,100));


    if( message == "hi"){

        textView.setTextSize(80);
    }


    // Set the text view as the activity layout
    setContentView(textView);







    }}



    [       if( message == "hi"){

        textView.setTextSize(80);
    } ]

It didn't work why? And how to fix it and thank you