readme

Signed-off-by: mayunteng_1 <mayunteng@huawei.com> Change-Id: I413a442a67001ad8811ea467ff8df71908c61554
2026-07-01 06:48:22 -04:00 · 2022-10-09 16:49:44 +08:00
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+# libevdev - wrapper library for evdev input devices
+
+libevdev is a wrapper library for evdev devices. it moves the common tasks when dealing with evdev devices into a library and provides a library interface to the callers, thus avoiding erroneous ioctls, etc.
+
+The eventual goal is that libevdev wraps all ioctls available to evdev devices, thus making direct access unnecessary.
+
+
+## Directory structure
+
+```
+README.md                   English description
+README_zh.md                Chinese description
+export_include/libevdev/    API Definition
+include/                    Reference header file
+libevdev/                   Encapsulation layer implementation
+README.OpenSource           Open Source Description
+```
+
+## How OpenHarmony integrates libevdev
+### 1.Header file import
+```c
+#define EVDEV_H
+#include <libevdev/libevdev.h>
+```
+### 2.BUILD.gn add Reference
+```c
+public_deps += ["//third_party/libevdev:libevdev"]
+```
+### 3.Example of calling libevdev function
+```c
+// Below is a simple example that shows how libevdev could be used. This example opens a device, checks for relative axes and a left mouse button and if it finds them monitors the device to print the event.
+
+// open a device
+struct libevdev *dev = NULL;
+int fd;
+int rc = 1;
+ 
+fd = open("/dev/input/event0", O_RDONLY|O_NONBLOCK);
+rc = libevdev_new_from_fd(fd, &dev);
+if (rc < 0) {
+        fprintf(stderr, "Failed to init libevdev (%s)\n", strerror(-rc));
+        exit(1);
+}
+// print the device info
+printf("Input device name: \"%s\"\n", libevdev_get_name(dev));
+printf("Input device ID: bus %#x vendor %#x product %#x\n",
+       libevdev_get_id_bustype(dev),
+       libevdev_get_id_vendor(dev),
+       libevdev_get_id_product(dev));
+// hecks for relative axes and a left mouse button
+if (!libevdev_has_event_type(dev, EV_REL) ||
+    !libevdev_has_event_code(dev, EV_KEY, BTN_LEFT)) {
+        printf("This device does not look like a mouse\n");
+        exit(1);
+}
+ 
+ // monitors the device to print the event
+do {
+        struct input_event ev;
+        rc = libevdev_next_event(dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);
+        if (rc == 0)
+                printf("Event: %s %s %d\n",
+                       libevdev_event_type_get_name(ev.type),
+                       libevdev_event_code_get_name(ev.type, ev.code),
+                       ev.value);
+} while (rc == 1 || rc == 0 || rc == -EAGAIN);
+```
+
+## libevdev Working with documents
+
+Code gitlab https://gitlab.freedesktop.org/libevdev/libevdev.git
+
+Official API Document  http://www.freedesktop.org/software/libevdev/doc/latest/
+
+Detailed API definition https://www.freedesktop.org/software/libevdev/doc/latest/libevdev_8h.html
+
+Patches https://gitlab.freedesktop.org/libevdev/libevdev/merge_requests/
+
+Bugs https://gitlab.freedesktop.org/libevdev/libevdev/issues/
+
+Questions http://lists.freedesktop.org/mailman/listinfo/input-tools
+
+
+## License
+
+See [LICENSE](MITLicense).
+
+---
+
@@ -0,0 +1,89 @@
+# libevdev - wrapper library for evdev input devices
+
+libevdev是evdev设备的包装库。它将处理evdev设备时的常见任务移动到库中，并向调用方提供库接口，从而避免错误的ioctl等。
+
+最终目标是libevdev包装了evdev设备可用的所有ioctl，因此不需要直接访问。
+
+
+## 目录结构
+
+```
+README.md                   英文说明
+README_zh.md                中文说明
+export_include/libevdev/    API定义
+include/                    引用头文件
+libevdev/                   封装层实现
+README.OpenSource           开源说明
+```
+
+## OpenHarmony如何集成libevdev
+### 1.头文件引入
+```c
+#define EVDEV_H
+#include <libevdev/libevdev.h>
+```
+### 2.BUILD.gn添加引用
+```c
+public_deps += ["//third_party/libevdev:libevdev"]
+```
+### 3.调用libevdev函数过程举例
+```c
+// 下面是一个简单的示例，展示了如何使用libevdev。此示例打开一个设备，检查相对坐标和鼠标左键，如果找到，则监听设备并打印输入事件
+
+// 打开一个输入设备
+struct libevdev *dev = NULL;
+int fd;
+int rc = 1;
+ 
+fd = open("/dev/input/event0", O_RDONLY|O_NONBLOCK);
+rc = libevdev_new_from_fd(fd, &dev);
+if (rc < 0) {
+        fprintf(stderr, "Failed to init libevdev (%s)\n", strerror(-rc));
+        exit(1);
+}
+// 打印输入设备信息
+printf("Input device name: \"%s\"\n", libevdev_get_name(dev));
+printf("Input device ID: bus %#x vendor %#x product %#x\n",
+       libevdev_get_id_bustype(dev),
+       libevdev_get_id_vendor(dev),
+       libevdev_get_id_product(dev));
+// 检查相对坐标和鼠标左键
+if (!libevdev_has_event_type(dev, EV_REL) ||
+    !libevdev_has_event_code(dev, EV_KEY, BTN_LEFT)) {
+        printf("This device does not look like a mouse\n");
+        exit(1);
+}
+ 
+ // 监听该设备并打印输入事件
+do {
+        struct input_event ev;
+        rc = libevdev_next_event(dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);
+        if (rc == 0)
+                printf("Event: %s %s %d\n",
+                       libevdev_event_type_get_name(ev.type),
+                       libevdev_event_code_get_name(ev.type, ev.code),
+                       ev.value);
+} while (rc == 1 || rc == 0 || rc == -EAGAIN);
+```
+
+## libevdev使用文档
+
+代码仓库 https://gitlab.freedesktop.org/libevdev/libevdev.git
+
+API官方文档  http://www.freedesktop.org/software/libevdev/doc/latest/
+
+API详细定义 https://www.freedesktop.org/software/libevdev/doc/latest/libevdev_8h.html
+
+补丁包 https://gitlab.freedesktop.org/libevdev/libevdev/merge_requests/
+
+Bug上报 https://gitlab.freedesktop.org/libevdev/libevdev/issues/
+
+问题反馈 http://lists.freedesktop.org/mailman/listinfo/input-tools
+
+
+## License
+
+见 [LICENSE](MITLicense).
+
+---
+