关于TextView不能刷新的问题

[yyflxl]

有如下代码，请帮忙指教，为什么我按了按键S后，我的settext没有起到作用，谢谢！
public class MainActivity extends AppCompatActivity {
private TextView Tv;
private EditText Et;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findView();
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event){
event.startTracking();
char ch = Character.toLowerCase(event.getDisplayLabel());
if('s'==ch){
//Animation scale = AnimationUtils.loadAnimation(MainActivity.this,R.anim.anim);
//Tv.startAnimation(scale);
Tv.setText("newone new");
}
return super.onKeyDown(keyCode,event);//true;
}

@Override
public boolean onKeyLongPress(int keyCode, KeyEvent event){
char ch = Character.toLowerCase(event.getDisplayLabel());
if('s'==ch){
//Animation scale = AnimationUtils.loadAnimation(MainActivity.this,R.anim.anim);
//Tv.startAnimation(scale);
Tv.setText("newone new");
}
return super.onKeyLongPress(keyCode,event);
}

private void findView(){
Tv = (TextView)findViewById(R.id.Tv);
Et = (EditText) findViewById(R.id.Et);
}
}

[xing880307]

调用notify方法刷新