On the new Activity,

I want to ask that how can I use "if" structure in the new activity which is related to a string on the main activity.

here is my new activity ;

public class yeniaktivite extends Activity {
    public ImageView Abir;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.yeniaktivite);
        Intent intent = getIntent();
        String id = intent.getStringExtra("key");

        if (id == "A2") {
            Toast.makeText(getApplicationContext(), id, Toast.LENGTH_LONG).show();
        }
        Abir = (ImageView) findViewById(R.id.imageView1);
        Abir.setImageResource(R.drawable.abir);
    }

}

this code ignores the if structure on running