Src com。exceple。lilin MainActivity。javapackage com.example。lilin；import android.app.Activity；import android。os。Bundle；import android.view。View；import android。view.View.OnClickListener；import android。widget.Button;import android。widget。EditText；public class MainActivity extends Activity ｛ /** Called when the activity is first created。 ＊/private Button button1=null；private Button button2=null；private Button button3=null;private Button button4=null;private Button button5=null;private Button button6=null;private Button button7=null;private Button button8=null;private Button button9=null；private Button button0=null;private Button buttonAdd=null;private Button buttonMinus=null；private Button buttonClear=null;private Button buttonMultiple=null;private Button buttonDiv=null；private Button buttonResult=null；private EditText et=null;String a=””;int symbol；double x；double y； @Override public void onCreate(Bundle savedInstanceState） ｛ super。onCreate(savedInstanceState); setContentView(R.layout.fragment_main）； button0=（Button）findViewById(R.id。button_0）; button1=（Button)findViewById（R。id.button_1）; button2=(Button）findViewById(R.id。button_2); button3=（Button）findViewById（R.id。button_3）; button4=（Button)findViewById（R.id.button_4）; button5=（Button)findViewById（R。id。button_5）； button6=(Button)findViewById(R。id.button_6）； button7=（Button）findViewById(R。id.button_7）； button8=(Button)findViewById(R。id。button_8）; button9=(Button）findViewById(R。id.button_9）； buttonAdd=(Button)findViewById(R.id。button_add); buttonMinus=(Button）findViewById(R。id。button_minus）; buttonClear=(Button）findViewById（R.id。button_clear）; buttonMultiple=（Button)findViewById(R。id.button_multiple); buttonDiv=(Button)findViewById（R。id.button_div)； buttonResult=(Button）findViewById(R。id。button_result）; et=（EditText)findViewById(R。id。res...
