android 实现两个数字的乘法，页面之间的传值 以及菜单下拉列表的使用

package com.example.test1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
private EditText factorOne;
private EditText factorTwo;
private Button calculate;
private TextView symbol;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 根据空间ID 取得代表控件的对象
factorOne = (EditText) findViewById(R.id.factone);
factorTwo = (EditText) findViewById(R.id.facttwo);
symbol = (TextView) findViewById(R.id.symbol);
calculate = (Button) findViewById(R.id.calculate);

// 为symbol和calculate设置显示的值
symbol.setText(R.string.symbol);
calculate.setText(R.string.calculator);

// 给calculate设置绑定事件
calculate.setOnClickListener(new CalculateListener());
}

// 编写一个监听器

class CalculateListener implements OnClickListener {

@Override
public void onClick(View arg0) {
// 1.取得两个EditText的值
String factorOneStr = factorOne.getText().toString();
String factorTwoStr = factorTwo.getText().toString();
// 2.将这两个值存放到Intent对象当中
Intent it = new Intent();
it.putExtra("one", factorOneStr);
it.putExtra("two", factorTwoStr);
it.setClass(MainActivity.this, ResultActivity.class);
// 使用这个Intent对象来启动ResultActivity
MainActivity.this.startActivity(it);

}
}

// 添加回调函数,当客户点击menu按钮时调用该方法
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
menu.add(0, 1, 1, R.string.exit);
menu.add(0, 2, 2, R.string.about);
return super.onCreateOptionsMenu(menu);
}

// 为menu添加动作,也是一个回调函数,当客户点击菜单当中的某一个选项时调用该方法
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == 1) {
finish();
}
return super.onOptionsItemSelected(item);

}

}

nextpage.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {

}
});

package com.example.test1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class ResultActivity extends Activity{
private TextView resultView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.result);
resultView= (TextView) findViewById(R.id.result);
//得到Intent对象的值
Intent it = getIntent();
String factorOneStr =it.getStringExtra("one");
String factorTwoStr =it.getStringExtra("two");
int factorOneInt=Integer.parseInt(factorOneStr);
int factorTwoInt=Integer.parseInt(factorTwoStr);
int result =factorOneInt*factorTwoInt;
resultView.setText(result+"");
}

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<EditText
android:id="@+id/factone"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10" />

<TextView
android:id="@+id/symbol"
android:layout_width="987dp"
android:layout_height="124dp"
android:text="@string/hello" />

<EditText
android:id="@+id/facttwo"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:ems="10" >

<requestFocus />
</EditText>

<Button
android:id="@+id/calculate"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>

</LinearLayout>

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
android:id="@+id/result"
android:layout_width="987dp"
android:layout_height="77dp" />

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, MainActivity</string>

<string name="app_name">test1</string>
<string name="action_settings">Settings</string>
<string name="calculator">计算</string>
<string name="symbol">乘以</string>
<string name="exit">退出</string>
<string name="about">关于</string>

</resources>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test1"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.test1.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.test1.ResultActivity"
android:theme="@style/AppTheme" >
</activity>
</application>

</manifest>