1. 下载libusb库。
可以到libusb库的官网(https://libusb.info/)或者是其官方的github仓库(https://github.com/libusb/libusb/releases)上下载最新的libusb库源码。
2. 添加libusb库到android studio项目中。
这里以源码编译的方式添加，使用的仍然是ndk-build的方式，而非cmake，使用源码编译的好处在于，可以随时调试libusb库的源码，方便加log。
2.1 在app/src/main目录下新建一个jni目录，用于存放libusb库的源代码。
2.2 打开app目录下的build.gradle文件，指定JNI目录：
2.3 在jni目录下新建libusb-support目录和makefile文件，libusb-support目录用于存放libusb库的源代码。
这里单独新建一个libusb-support目录的目的在于，将来可能会有很多个第三方模块，比如libusb,libyuv, sdl，分目录存放可以划分得更清楚，可以直接把libusb的代码放到jni目录下，只要makefile能找到就行。
Android.mk
# # Copyright (c) 2019 Realsil.Inc. All rights reserved. # include $(call all-subdir-makefiles)
Application.mk
# # Copyright (c) 2019 SEP.Inc. All rights reserved. # APP_ABI := all APP_LDFLAGS := -llog
最终目录结构如下：
2.3 拷贝libusb库的源代码到libusb-support目录
打开下载的libusb库源代码，找到libusb文件夹，将整个文件拷贝到libusb-support目录下，我下载的是1.0.23版本：
打开android文件夹，拷贝config.h文件到libusb-support目录下
打开jni文件夹，拷贝Android.mk、libusb.mk文件到libusb-support目录下：
最终目录结构如下：
接下来修改Android.mk和libusb.mk文件，默认编译出来的库会包含一些测试用例和示例代码，我们不需要它。
修改Android.mk, 注释掉example.mk和tests.mk
# Android build config for libusb, examples and tests # Copyright © 2012-2013 RealVNC Ltd. <toby.gray@realvnc.com> # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA # LOCAL_PATH:= $(call my-dir) include $(LOCAL_PATH)/libusb.mk # include $(LOCAL_PATH)/examples.mk # include $(LOCAL_PATH)/tests.mk
修改libusb.mk, 更新当前源代码的位置：
# Android build config for libusb # Copyright © 2012-2013 RealVNC Ltd. <toby.gray@realvnc.com> # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA # LOCAL_PATH:= $(call my-dir) LIBUSB_ROOT_REL:= . LIBUSB_ROOT_ABS:= $(LOCAL_PATH) # libusb include $(CLEAR_VARS) LIBUSB_ROOT_REL:= . LIBUSB_ROOT_ABS:= $(LOCAL_PATH) LOCAL_SRC_FILES := $(LIBUSB_ROOT_REL)/libusb/core.c $(LIBUSB_ROOT_REL)/libusb/descriptor.c $(LIBUSB_ROOT_REL)/libusb/hotplug.c $(LIBUSB_ROOT_REL)/libusb/io.c $(LIBUSB_ROOT_REL)/libusb/sync.c $(LIBUSB_ROOT_REL)/libusb/strerror.c $(LIBUSB_ROOT_REL)/libusb/os/linux_usbfs.c $(LIBUSB_ROOT_REL)/libusb/os/poll_posix.c $(LIBUSB_ROOT_REL)/libusb/os/threads_posix.c $(LIBUSB_ROOT_REL)/libusb/os/linux_netlink.c $(LIBUSB_ROOT_REL)/libusb/realsil_usb_audio.c $(LIBUSB_ROOT_REL)/libusb/jnihelp.cpp LOCAL_C_INCLUDES += $(LOCAL_PATH)/ $(LIBUSB_ROOT_ABS)/libusb $(LIBUSB_ROOT_ABS)/libusb/os LOCAL_EXPORT_C_INCLUDES := $(LIBUSB_ROOT_ABS)/libusb LOCAL_LDLIBS := -llog LOCAL_MODULE := usb include $(BUILD_SHARED_LIBRARY)
其中的 realsil_usb_audio.c 和 jnihelp.cpp是我自己添加的调用libusb库的code, 可不用在意。
3. 编译链接
在任意文件夹下右击，选择“Link C++ Project with Gradle”
在Build System的下拉列表中选择ndk-build的编译方式，并指定所有模块的makefile文件位置：
点OK， 此时编译系统就会自动开始构建，注意到此时文件夹的目录颜色已修改，且app目录下的build.gradle文件也进行了更新。
接下来就可以在相应的C代码里编写调用libusb库的相应逻辑了。
参考链接：
1. Android从USB声卡录制高质量音频-----USB API测试