一、前言：
大家好，今天给大家分享一下Android中的拿来主义，我们时常会碰到一个自己觉得很漂亮很帅气的应用(apk),所以我们会尝试用WinRAR等之类工具查看，而一般的应用程序打包后的目录通常是这样的如下图：
当然res里的图片是可以拿来就用的(笔者的好多应用的图片都是从别人的apk里扣出来的)，而诸如layout里的布局及权限文件 (AndroidManifest.xml)已经是一堆乱码了，完全看不懂，想看看别人是怎么布局的都不容易。还有源代码都被编译成了 classes.dex，完全看不出什么线索。基于以上的困惑，笔者给大家分享一下Android中的拿来主义。
二、所需工具(点击各自连接进入下载页面)：
1.AXMLPrinter2.jar
2.baksmali.jar
3.smali.jar
三、准备工作
为了方便起见，作者把AXMLPrinter2.jar, 还有baksmali.jar,还有smali.jar(下下来为了方便重命名)，放在Android SDK tools文件夹中如下图所示:
为了便于大家更容易程序比对，作者写了一个简单的应用(叫APKInstaller)目录结构如下图所示:
四、开始拿来主义
1.用 AXMLPrinter2.jar查看apk中的布局xml文件:
将ApkInstaller应用生成的ApkInstaller.apk(为了方便起见放到tools目录里)用WinRAR等工具打开，将res/layout/main.xml解压出来(也还是放在tools目录里哦)
打开main.xml文件，内容如下(一堆天文):
这时候AXMLPrinter2.jar派上用场了，打开cmd终端，一直进入到tools目录下，输入如下命令:
java -jar AXMLPrinter2.jar main.xml > main.txt. (如下图所示)
打开main.txt代码如下(是不是有个123了呵呵~):
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<?xml version="1.0" encoding="utf-8"?>??
<LinearLayout??
??? xmlns:android="http://schemas.android.com/apk/res/android"
??? android:orientation="1"
??? android:layout_width="-1"
??? android:layout_height="-1"
??? >??
??? <WebView??
??????? android:id="@7F050000"
??????? android:layout_width="-1"
??????? android:layout_height="-2"
??????? >??
??? </WebView>??
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="1"
android:layout_width="-1"
android:layout_height="-1"
>
<WebView
?? android:id="@7F050000"
?? android:layout_width="-1"
?? android:layout_height="-2"
?? >
</WebView>
</LinearLayout>
为了比对打开源程序中的main.xml代码如下(大家比对一下吧):
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<?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"
??? >??
<WebView??
??? android:id="@+id/apk_web"
??? android:layout_height="wrap_content"
??? android:layout_width="fill_parent"
??????
/>??
</LinearLayout>
<?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"
??? >
<WebView
android:id="@+id/apk_web"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
/>
</LinearLayout>
2.用baksmali.jar反编译classes.dex:
将ApkInstaller.apk里的classes.dex解压到tools目录里，然后baksmali.jar就派上用场了，在cmd命令行里输入如下命令:
java -jar baksmali.jar -o classout/ classes.dex .(如下图所示:)
你将会发现在tools里多一个classout文件夹里面(我代码的包目录结构清晰可见呀),如下图所示:
从上面看出除了Android本身资源的类R开头的，我的源程序里只有一个ApkInstaller.java，完全吻合，真TMD的猥琐呵呵~
下面我们看一下ApkInstaller.smali内容是什么，如以下代码：
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.class public Lcom/tutor/apkinstaller/ApkInstaller;??
.super Landroid/app/Activity;??
.source "ApkInstaller.java"
# instance fields??
.field private apkWeb:Landroid/webkit/WebView;??
# direct methods??
.method public constructor <init>()V??
??? .registers 1
??? .prologue??
??? .line 8
??? invoke-direct {p0}, Landroid/app/Activity;-><init>()V??
??? return-void
.end method??
# virtual methods??
.method public onCreate(Landroid/os/Bundle;)V??
??? .registers 5
??? .parameter "savedInstanceState"
??? .prologue??
??? .line 13
??? invoke-super {p0, p1}, Landroid/app/Activity;->onCreate(Landroid/os/Bundle;)V??
??? .line 14
??? const/high16 v2, 0x7f03
??? invoke-virtual {p0, v2}, Lcom/tutor/apkinstaller/ApkInstaller;->setContentView(I)V??
??? .line 15
??? const/high16 v2, 0x7f05
??? invoke-virtual {p0, v2}, Lcom/tutor/apkinstaller/ApkInstaller;->findViewById(I)Landroid/view/View;??
??? move-result-object v2??
??? check-cast v2, Landroid/webkit/WebView;??
??? iput-object v2, p0, Lcom/tutor/apkinstaller/ApkInstaller;->apkWeb:Landroid/webkit/WebView;??
??? .line 16
??? iget-object v2, p0, Lcom/tutor/apkinstaller/ApkInstaller;->apkWeb:Landroid/webkit/WebView;??
??? invoke-virtual {v2}, Landroid/webkit/WebView;->getSettings()Landroid/webkit/WebSettings;??
??? move-result-object v1??
??? .line 17
??? .local v1, webSettings:Landroid/webkit/WebSettings;??
??? const/4 v2, 0x1
??? invoke-virtual {v1, v2}, Landroid/webkit/WebSettings;->setJavaScriptEnabled(Z)V??
??? .line 19
??? const-string v0, "http://frankiewei.net/apk/demos/main/index.html#home"
??? .line 20
??? .local v0, apkUrl:Ljava/lang/String;??
??? iget-object v2, p0, Lcom/tutor/apkinstaller/ApkInstaller;->apkWeb:Landroid/webkit/WebView;??
??? invoke-virtual {v2, v0}, Landroid/webkit/WebView;->loadUrl(Ljava/lang/String;)V??
??? .line 21
??? return-void
.end method
.class public Lcom/tutor/apkinstaller/ApkInstaller;
.super Landroid/app/Activity;
.source "ApkInstaller.java"
# instance fields
.field private apkWeb:Landroid/webkit/WebView;
# direct methods
.method public constructor <init>()V
??? .registers 1
??? .prologue
??? .line 8
??? invoke-direct {p0}, Landroid/app/Activity;-><init>()V
??? return-void
.end method
# virtual methods
.method public onCreate(Landroid/os/Bundle;)V
??? .registers 5
??? .parameter "savedInstanceState"
??? .prologue
??? .line 13
??? invoke-super {p0, p1}, Landroid/app/Activity;->onCreate(Landroid/os/Bundle;)V
??? .line 14
??? const/high16 v2, 0x7f03
??? invoke-virtual {p0, v2}, Lcom/tutor/apkinstaller/ApkInstaller;->setContentView(I)V
??? .line 15
??? const/high16 v2, 0x7f05
??? invoke-virtual {p0, v2}, Lcom/tutor/apkinstaller/ApkInstaller;->findViewById(I)Landroid/view/View;
??? move-result-object v2
??? check-cast v2, Landroid/webkit/WebView;
??? iput-object v2, p0, Lcom/tutor/apkinstaller/ApkInstaller;->apkWeb:Landroid/webkit/WebView;
??? .line 16
??? iget-object v2, p0, Lcom/tutor/apkinstaller/ApkInstaller;->apkWeb:Landroid/webkit/WebView;
??? invoke-virtual {v2}, Landroid/webkit/WebView;->getSettings()Landroid/webkit/WebSettings;
??? move-result-object v1
??? .line 17
??? .local v1, webSettings:Landroid/webkit/WebSettings;
??? const/4 v2, 0x1
??? invoke-virtual {v1, v2}, Landroid/webkit/WebSettings;->setJavaScriptEnabled(Z)V
??? .line 19
??? const-string v0, "http://frankiewei.net/apk/demos/main/index.html#home"
??? .line 20
??? .local v0, apkUrl:Ljava/lang/String;
??? iget-object v2, p0, Lcom/tutor/apkinstaller/ApkInstaller;->apkWeb:Landroid/webkit/WebView;
??? invoke-virtual {v2, v0}, Landroid/webkit/WebView;->loadUrl(Ljava/lang/String;)V
??? .line 21
??? return-void
.end method
同样为了比对我们看一下ApkInstaller.java的源代码如下:
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package com.tutor.apkinstaller;??
import android.app.Activity;??
import android.os.Bundle;??
import android.webkit.WebSettings;??
import android.webkit.WebView;??
public class ApkInstaller extends Activity {??
?????
??? private WebView apkWeb;??
??? @Override
??? public void onCreate(Bundle savedInstanceState) {??
??????? super.onCreate(savedInstanceState);??
??????? setContentView(R.layout.main);??
?????? apkWeb = (WebView)findViewById(R.id.apk_web);??
?????? WebSettings webSettings = apkWeb.getSettings();??
?????? webSettings.setJavaScriptEnabled(true);??
????????
?????? String apkUrl = "http://frankiewei.net/apk/demos/main/index.html#home";??
?????? apkWeb.loadUrl(apkUrl);??
??? }??
}
package com.tutor.apkinstaller;
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;
public class ApkInstaller extends Activity {
??
private WebView apkWeb;
??? @Override
??? public void onCreate(Bundle savedInstanceState) {
??????? super.onCreate(savedInstanceState);
??????? setContentView(R.layout.main);
?????? apkWeb = (WebView)findViewById(R.id.apk_web);
?????? WebSettings webSettings = apkWeb.getSettings();
?????? webSettings.setJavaScriptEnabled(true);
?????
?????? String apkUrl = "http://frankiewei.net/apk/demos/main/index.html#home";
?????? apkWeb.loadUrl(apkUrl);
??? }
}
我相信大家 已经能看出来门道来了吧，hoho~
3.用smali.jar编译classout成classes.dex:
我们上一步已经将classes.dex反编译成了.smali文件，好了，我们看看smali文件看够了，在偿试把它编译成classes.dex吧，
输入如下命令:java -jar smali.jar classout/ -o classes.dex. 如下图所示:
我们可以将新生成的classes.dex塞入ApkInstaller.apk里覆盖原来的classes.dex文件，这样我们的apk还是一样能用的哦