if else android coding

i am doing a if else android coding but it seen that the code don't take data string from selection which is a "textview" and match it to my pre define in the condition of the if else. i wonder is it my coding is wrong? below is my codes.

private static final String[] items={"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "R"};

@Override
public void onCreate(Bundle icicle) {
  super.onCreate(icicle);

  Fabric.with(this, new Crashlytics());

  setContentView(R.layout.activity_main);

  selection=(TextView)findViewById(R.id.text0);  
  Spinner spin=(Spinner)findViewById(R.id.spinner0);  
  result=(TextView)findViewById(R.id.result);

  spin.setOnItemSelectedListener(this);

  ArrayAdapter<String> aa=new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, items);

  aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  spin.setAdapter(aa);
  result.setText("");



  if (selection.equals(a)){
      int aaa = (1*100);
      result.setText(String.valueOf(aaa));

  }

  else if (selection.equals("1")){
      int aaa = (2*10);
      result.setText(aaa + "");
  }

  else if (selection.equals("2")){
      int aaa = (3*1);
      result.setText(String.valueOf(aaa));

  }

  else if (bb.equals("R")){
      result.setText(".");
  }


}