startActivityForResult and onActivityResult

startActivityForResult 开启Activity 组织数据之后 发送，onActivityResult 接受数据

 1  public class MyActivity extends Activity { 2      ... 3  4      static final int PICK_CONTACT_REQUEST = 0; 5  6      protected boolean onKeyDown(int keyCode, KeyEvent event) { 7          if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) { 8              // When the user center presses, let them pick a contact. 9              startActivityForResult(10                  new Intent(Intent.ACTION_PICK,11                  new Uri("content://contacts")),12                  PICK_CONTACT_REQUEST);13             return true;14          }15          return false;16      }17 18      protected void onActivityResult(int requestCode, int resultCode,19              Intent data) {20          if (requestCode == PICK_CONTACT_REQUEST) {21              if (resultCode == RESULT_OK) {22                  // A contact was picked.  Here we will just display it23                  // to the user.24                  startActivity(new Intent(Intent.ACTION_VIEW, data));25              }26          }27      }