android eclipse中在androidmanifest.xml注册的问题-----代码

Main.java:

package com.example.activity003;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Main extends Activity {
  private EditText factorone;
  private EditText factortwo;
  private TextView symbol;
  private Button calculate;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //根据控件的ID来取得代表控件的对象
        factorone = (EditText)findViewById(R.id.factorone);
        factortwo = (EditText)findViewById(R.id.factortwo);
        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.calculate);
        //将监听器的对象绑定到按钮对象上面
        calculate.setOnClickListener(new CalculateListener());
    }
    class CalculateListener implements OnClickListener{
        public void onClick(View v) {
   // 取得两个EditText控件的值
   String factoroneStr = factorone.getText().toString();
   String factortwoStr = factortwo.getText().toString();
   //将这两个值存放到Intent对象当中
   Intent intent = new Intent();
   intent.putExtra("one", "factoronestr");
   intent.putExtra("two","factortwostr");
   intent.setClass(Main.this,ResultActivity.class);
   //使用这个Intent对象来启动ResultActivity
   Main.this.startActivity(intent);   
  } 
    }
}
main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    >
    <EditText
         android:id="@+id/factorone"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         />
    <EditText
        android:id="@+id/factortwo"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
          />
    <TextView
        android:id="@+id/symbol"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
    <Button
        android:id="@+id/calculate"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />
</LinearLayout>

ResultActivity.java:

package com.example.activity003;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
//接收从Activity当中所传递的值
//计算两个值的积
//将计算的结果显示在Activity上
public class ResultActivity extends Activity{
 private TextView resultView;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  resultView = (TextView)findViewById(R.id.result);
  //得到Intent对象当中的值
  Intent intent = getIntent();
  String factoroneStr = intent.getStringExtra("one");
  String factortwoStr = intent.getStringExtra("two");
  int factoroneInt = Integer.parseInt(factoroneStr);
  int factortwoInt = Integer.parseInt(factortwoStr);
  //计算两个值的积
  int result = factoroneInt * factortwoInt;
  resultView.setText(result + "");
 }
}

result.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    >
    <TextView
        android:id="@+id/result"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
     />  
</LinearLayout>

string.xml:

<resources>
    <string name="app_name">Activity003</string>
    <string name="hello_world">Hello world!</string>
    <string name="menu_settings">Settings</string>
    <string name="title_activity_main">Main</string>
    <string name="symbol">乘以</string>
    <string name="calculate">计算</string>
</resources>

AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.activity003"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".Main"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ResultActivity"></activity>
       </application>
</manifest>