apktool+dex2jar+jd_gui

apktool: 可以解析资源文件，比如布局文件xml等，方便查看。

使用方法：

Apktool v1.4.1 - a tool for reengineering Android apk files
Copyright 2010 Ryszard Wi?niewski <brut.alll@gmail.com>
Apache License 2.0 (http://www.apache.org/licenses/LICENSE-2.0)

Usage: apktool [-v|--verbose] COMMAND [...]

COMMANDs are:

    d[ecode] [OPTS] <file.apk> [<dir>]
        Decode <file.apk> to <dir>.

        OPTS:

        -s, --no-src
            Do not decode sources.
        -r, --no-res
            Do not decode resources.
        -d, --debug
            Decode in debug mode. Check project page for more info.
        -f, --force
            Force delete destination directory.
        -t <tag>, --frame-tag <tag>
            Try to use framework files tagged by <tag>.
        --keep-broken-res
            Use if there was an error and some resources were dropped, e.g.:
            "Invalid config flags detected. Dropping resources", but you
            want to decode them anyway, even with errors. You will have to
            fix them manually before building.
    b[uild] [OPTS] [<app_path>] [<out_file>]
        Build an apk from already decoded application located in <app_path>.

        It will automatically detect, whether files was changed and perform
        needed steps only.

        If you omit <app_path> then current directory will be used.
        If you omit <out_file> then <app_path>/dist/<name_of_original.apk>
        will be used.

        OPTS:

        -f, --force-all
            Skip changes detection and build all files.
        -d, --debug
            Build in debug mode. Check project page for more info.

    if|install-framework <framework.apk> [<tag>]
        Install framework file to your system.

dex2jar:可以将dex文件转换成jar文件

用法：

1.将apk文件后缀改成rar，然后解压，取出其中的class.dex，放到任意位置；

2.进入cmd，cd到dex2jar所在文件夹，输入命令dex2jar.bat %class.dex所在目录%\class.dex

3. 命令完成后在%class.dex所在目录%就会生成jar文件

jd_gui:能够将jar文件反编译成java代码

用法:

打开jd_gui,然后将jar包拖放到主界面，就可以看到源代码了。