Android簡易計算機

packagetw.android;importandroid.os.Bundle;importandroid.app.Activity;importandroid.view.Menu;importandroid.view.View;importandroid.view.View.OnClickListener;importandroid.widget.Button;importandroid.widget.EditText;importandroid.widget.TextView;publicclassMainextendsActivity{privateclassBtnListeneri