上面的Button OnClick事件代码为什么不会执行

   public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity2);                button1=(Button) this.findViewById(R.id.button1);        button1.setOnClickListener(BtnOnClickListener);  }    public OnClickListener BtnOnClickListener=new OnClickListener(){        public void OnClick(View arg0){            Toast toast=Toast.makeText(getApplicationContext(), "test",Toast.LENGTH_LONG);            toast.show();            Intent it=new Intent(Activity2.this,MainActivity.class);            Activity2.this.startActivity(it);            finish();        }