01_03_say_hello_to_Android

01_03_say_hello_to_Android
1、创建一个Android应用程序的步骤
2、Android应用程序的目录结构
    src目录：存放源代码
    gen目录：由SDK自动产生。其中R.java文件是资源文件
    

/* AUTO-GENERATED FILE.  DO NOT MODIFY.
 *R.java文件
 * This class was automatically generated by the
 * aapt tool from the resource data it found.  It
 * should not be modified by hand.
 */

package com.lwb.myhelloword;

public final class R {
    public static final class attr {
    }
    public static final class dimen {
        /**  Default screen margins, per the Android Design guidelines.

         Customize dimensions originally defined in res/values/dimens.xml (such as
         screen margins) for sw720dp devices (e.g. 10" tablets) in landscape here.

         */
        public static final int activity_horizontal_margin=0x7f040000;
        public static final int activity_vertical_margin=0x7f040001;
    }
    public static final class drawable {
        public static final int ic_launcher=0x7f020000;
    }
    public static final class id {
        public static final int action_settings=0x7f080000;
    }
    public static final class layout {
        public static final int activity_hello=0x7f030000;
    }
    public static final class menu {
        public static final int hello=0x7f070000;
    }
    public static final class string {
        public static final int action_settings=0x7f050001;
        public static final int app_name=0x7f050000;
        public static final int hello_world=0x7f050002;
    }
    public static final class style {
        /**
        Base application theme, dependent on API level. This theme is replaced
        by AppBaseTheme from res/values-vXX/styles.xml on newer devices.


            Theme customizations available in newer API levels can go in
            res/values-vXX/styles.xml, while customizations related to
            backward-compatibility can go here.


        Base application theme for API 11+. This theme completely replaces
        AppBaseTheme from res/values/styles.xml on API 11+ devices.

 API 11 theme customizations can go here.

        Base application theme for API 14+. This theme completely replaces
        AppBaseTheme from BOTH res/values/styles.xml and
        res/values-v11/styles.xml on API 14+ devices.

 API 14 theme customizations can go here.
         */
        public static final int AppBaseTheme=0x7f060000;
        /**  Application theme.
 All customizations that are NOT specific to a particular API-level can go here.
         */
        public static final int AppTheme=0x7f060001;
    }
}

    Android 4.2目录：
       其中有这样的一个android.jar 路径是在D:\swpaket\study\adt-bundle-windows-x86-20130729\adt-bundle-windows-x86-20130729\sdk\platforms\android-18\android.jar
        表明：android应用的所有类文件均来源于android.jar中（这个含有很多的包）
    Android Private Libraries目录（该目录下有两个目录）
          Android  Dependencies目录：
           asserts目录：（放置任何文件）
    res目录：（在该目录下放置的任何文件，均会在R.java中产生一个id,可以通过这个id来使用这个文件）
        drawable(-hdpi,-ldpi,-mdpi，三个版本的分辨率的图片等)目录：
        layout：（放置布局布局文件main.xml,控制各种控件在Activity中的布局）
        values：（如：string.xml）
        如：string.xml  里边的键值也会在R.java中有唯一的id号

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">myhelloword</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>

</resources>

3、AndroidManifest.xml文件的作用  （

• Manfiest的意思：
• n. 载货单，货单；旅客名单
  • adj. 显然的，明显的；明白的
  • • vt. 证明，表明；显示
    • vi. 显示，出现
    
    

）
        AndroidManifest.xml整个程序的配置文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=""
    package="com.lwb.myhelloword"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
            android:name="com.lwb.myhelloword.HelloActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

4、Android相关资源文件的作用