Android起步--简单的乘法

在网上看了android的相关视频，本人也试着写了一些代码。现在我在这里贴出来，用来见证我学习android的历程。
先布局：
main.xml
Java代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<EditText
    android:id="@+id/num1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
/>
<TextView
    android:id="@+id/symbol"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
<EditText
    android:id="@+id/num2"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
/>
<Button
    android:id="@+id/buttonresult"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
/>
</LinearLayout>

result.xml
Java代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

<TextView
    android:id="@+id/result"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
/>
</LinearLayout>

strings.xml
Java代码
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello World, Activity03!</string>
    <string name="app_name">Activity03</string>
    <string name="symbol">乘以</string>
    <string name="buttonresult">计算</string>
    <string name="resultLable">result</string>
    <string name="exit">退出</string>
    <string name="about">关于</string>
    <style name="Text">
        <item name="android:textSize">18sp</item>
    </style>
    <style name="SpecialText" parent="@style/Text">
        <item name="android:textSize">18sp</item>
        <item name="android:textColor">#008</item>
    </style>
</resources>

AndroidManifest.xml
Java代码
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="org.hs"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="4" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Activity03"
                  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=".ResultActivity" android:label="@string/resultLable"></activity>
    </application>
</manifest>

Activity03.java
Java代码
package org.hs;

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 Activity03 extends Activity {
    /** Called when the activity is first created. */
    private EditText num1;
    private EditText num2;
    private TextView symbol;
    private Button buttonresult;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        num1 = (EditText) findViewById(R.id.num1);
        num2 = (EditText) findViewById(R.id.num2);
        symbol = (TextView) findViewById(R.id.symbol);
        buttonresult = (Button) findViewById(R.id.buttonresult);

//        symbol.setText("乘以");
//        buttonresult.setText("计算");
        symbol.setText(R.string.symbol);
        buttonr

补充：移动开发 , Android ,