1、需要的工具
git、vpn代理
2. 设置git代理（Google source 无法下载，git设置代理）
git config --global http.proxy "localhost:1080"
红色为代理的地址 如192.168.33.78：80
3. 下载Code
git clone https://android.googlesource.com/platform/frameworks/volley/
建议用一些稳定的vpn软件。
我用的SoftEnther VPN Client。不过很多连不上的。
4. 第三步已经下载了volley的源码。
其他源码的路径如下，如果不能下载，请将http改为https试试。
git clone http://android.git.kernel.org/kernel/common.git
git clone http://android.googlesource.com/platform/external/webkit.git
git clone http://android.googlesource.com/platform/development.git
git clone http://android.googlesource.com/platform/system/bluetooth.git
git clone http://android.googlesource.com/platform/external/freetype.git
git clone http://android.googlesource.com/platform/system/vold.git
git clone http://android.googlesource.com/platform/system/extras.git
git clone http://android.googlesource.com/platform/system/core.git
git clone http://android.googlesource.com/platform/frameworks/ex.git
git clone http://android.googlesource.com/platform/system/media.git
git clone http://android.googlesource.com/platform/frameworks/base.git
git clone http://android.googlesource.com/platform/system/netd.git
git clone http://android.googlesource.com/platform/packages/apps/AlarmClock.git
git clone http://android.googlesource.com/platform/packages/apps/Nfc.git
git clone http://android.googlesource.com/platform/system/wlan/ti.git
git clone http://android.googlesource.com/platform/packages/providers/ImProvider.git
git clone http://android.googlesource.com/platform/packages/apps/CertInstaller.git
git clone http://android.googlesource.com/platform/packages/apps/Tag.git
git clone http://android.googlesource.com/platform/packages/providers/TelephonyProvider.git
git clone http://android.googlesource.com/platform/hardware/qcom/media.git
git clone http://android.googlesource.com/platform/packages/providers/WebSearchProvider.git
git clone http://android.googlesource.com/platform/frameworks/opt/carddav.git
git clone http://android.googlesource.com/toolchain/manifest.git
git clone http://android.googlesource.com/toolchain/mpc.git
git clone http://android.googlesource.com/toolchain/build.git
git clone http://android.googlesource.com/device/sample.git
git clone http://android.googlesource.com/toolchain/gmp.git
git clone http://android.googlesource.com/toolchain/gold.git
git clone http://android.googlesource.com/toolchain/gcc.git
git clone http://android.googlesource.com/toolchain/mpfr.git
git clone http://android.googlesource.com/toolchain/benchmark.git
git clone http://android.googlesource.com/toolchain/gdb.git
git clone http://android.googlesource.com/kernel/omap.git
git clone http://android.googlesource.com/platform/packages/apps/Sync.git
git clone http://android.googlesource.com/platform/prebuilt.git
git clone http://android.googlesource.com/platform/dalvik.git
git clone http://android.googlesource.com/platform/external/tinyxml.git
git clone http://android.googlesource.com/platform/external/srec.git
git clone http://android.googlesource.com/platform/external/neven.git
git clone http://android.googlesource.com/platform/external/dhcpcd.git
git clone http://android.googlesource.com/platform/external/skia.git
git clone http://android.googlesource.com/platform/external/clearsilver.git
git clone http://android.googlesource.com/platform/external/elfutils.git
git clone http://android.googlesource.com/platform/hardware/ril.git
git clone http://android.googlesource.com/platform/external/icu4c.git
git clone http://android.googlesource.com/platform/external/netperf.git
git clone http://android.googlesource.com/platform/external/sqlite.git
git clone http://android.googlesource.com/platform/external/ping.git
git clone http://android.googlesource.com/platform/external/googleclient.git
git clone http://android.googlesource.com/platform/external/tremor.git
git clone http://android.googlesource.com/platform/packages/apps/Settings.git
git clone http://android.googlesource.com/platform/packages/providers/MediaProvider.git
git clone http://android.googlesource.com/platform/packages/apps/Email.git
git clone http://android.googlesource.com/platform/packages/providers/ContactsProvider.git
git clone http://android.googlesource.com/platform/packages/apps/Contacts.git
git clone http://android.googlesource.com/platform/packages/apps/Updater.git
git clone http://android.googlesource.com/platform/packages/apps/Stk.git
git clone http://android.googlesource.com/platform/packages/apps/Camera.git
git clone http://android.googlesource.com/platform/packages/apps/Launcher.git
git clone http://android.googlesource.com/platform/external/safe-iop.git
git clone http://android.googlesource.com/platform/packages/providers/DrmProvider.git
git clone http://android.googlesource.com/platform/external/bluetooth/bluez.git
git clone http://android.googlesource.com/platform/packages/apps/Mms.git
git clone http://android.googlesource.com/platform/packages/apps/Browser.git
git clone http://android.googlesource.com/platform/packages/providers/CalendarProvider.git
git clone http://android.googlesource.com/platform/packages/apps/Calculator.git
git clone http://android.googlesource.com/platform/frameworks/opt/com.google.android.git
git clone http://android.googlesource.com/platform/packages/apps/AccountsAndSyncSettings.git
git clone http://android.googlesource.com/platform/packages/apps/HTMLViewer.git
git clone http://android.googlesource.com/platform/packages/apps/GlobalSearch.git
git clone http://android.googlesource.com/platform/packages/providers/ManagementProvider.git
git clone http://android.googlesource.com/platform/packages/apps/PackageInstaller.git
git clone http://android.googlesource.com/platform/packages/providers/UserDictionaryProvider.git
git clone http://android.googlesource.com/platform/packages/apps/Provision.git
git clone http://android.googlesource.com/platform/packages/apps/Gallery3D.git
git clone http://android.googlesource.com/platform/frameworks/opt/emoji.git
git clone http://android.googlesource.com/platform/packages/apps/Phone.git
git clone http://android.googlesource.com/platform/packages/apps/Gallery.git
git clone http://android.googlesource.com/platform/external/svox.git
git clone http://android.googlesource.com/platform/system/vold.git
git clone http://android.googlesource.com/platform/system/wlan/ti.git
git clone http://android.googlesource.com/platform/packages/providers/ImProvider.git
git clone http://android.googlesource.com/platform/packages/providers/GoogleSubscribedFeedsProvider.git
git clone http://android.googlesource.com/platform/packages/apps/Launcher2.git
git clone http://android.googlesource.com/platform/packages/providers/DownloadProvider.git
git clone http://android.googlesource.com/platform/packages/apps/DeskClock.git
git clone http://android.googlesource.com/platform/packages/apps/SoundRecorder.git
git clone http://android.googlesource.com/platform/packages/apps/Protips.git
git clone http://android.googlesource.com/platform/packages/apps/Stk.git
git clone http://android.googlesource.com/platform/packages/apps/SpeechRecorder.git
git clone http://android.googlesource.com/platform/packages/apps/Music.git
git clone http://android.googlesource.com/platform/packages/apps/VoiceDialer.git
git clone http://android.googlesource.com/platform/packages/providers/GoogleContactsProvider.git
git clone http://android.googlesource.com/platform/packages/apps/IM.git
git clone http://android.googlesource.com/platform/packages/apps/QuickSearchBox.git
git clone http://android.googlesource.com/platform/packages/apps/GoogleSearch.git
git clone http://android.googlesource.com/platform/packages/providers/ApplicationsProvider.git
git clone http://android.googlesource.com/platform/frameworks/opt/com.google.android.googlelogin.git
需要哪一部分，可以进行单独下载。