Android实现简单加法计算器

package com.example.calculator;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {

 private TextView tv1;
 private EditText et1;
 private EditText et2;
 private Button btn;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tv1 = (TextView) this.findViewById(R.id.textView1);
  et1 = (EditText) this.findViewById(R.id.editText1);
  et2 = (EditText) this.findViewById(R.id.editText2);
  btn = (Button) this.findViewById(R.id.button1);
  btn.setOnClickListener(new View.OnClickListener() {
 
 @Override
 public void onClick(View v) {
  String inputText1 = et1.getText().toString();
    String inputText2 = et2.getText().toString();
    int num1 = Integer.valueOf(inputText1).intValue();
    int num2 = Integer.valueOf(inputText2).intValue();
    num1 = num1+num2;
    inputText1 = String.valueOf(num1);
   
    tv1.setText(inputText1);
 
 }
 });
 
 }


 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }
 
}

private EditText input1;
private EditText input2;
private TextView textView;
int num = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 input1 = (EditText)findViewById(R.id.shurukuan);
 input2 = (EditText)findViewById(R.id.shurukuan2);
 textView = (TextView)findViewById(R.id.textView2);

 Button Btn1 = (Button)findViewById(R.id.button3);
 Btn1.setOnClickListener(new Button.OnClickListener(){
  public void onClick(View v) {
   num= Integer.parseInt(input1.getText().toString()) + Integer.parseInt(input2.getText().toString());
   textView.setText(Integer.toString(num));

  }
 });
}