写一段 jNI(Java Native Interface)C++代码,用于扫描蓝牙设备并发送数据。
时间: 2024-03-23 20:36:02 浏览: 27
好的,以下是一个简单的JNI C++代码示例,用于扫描蓝牙设备并发送数据:
```
#include <jni.h>
#include <string>
#include <iostream>
#include <vector>
#include <cstring>
#include <unistd.h>
#include <sys/socket.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/rfcomm.h>
extern "C" JNIEXPORT jstring
JNICALL
Java_com_example_myapplication_MainActivity_scanAndSendData(JNIEnv *env, jobject /* this */)
{
std::string result = "";
// 扫描蓝牙设备
int max_attempts = 3;
int attempts = 0;
std::vector<std::string> addresses;
while (addresses.empty() && attempts < max_attempts) {
inquiry_info *ii = nullptr;
int num_rsp = 0;
int dev_id = hci_get_route(nullptr);
int sock = hci_open_dev(dev_id);
if (sock >= 0) {
ii = static_cast<inquiry_info *>(malloc(255 * sizeof(inquiry_info)));
num_rsp = hci_inquiry(dev_id, 8, 255, nullptr, &ii, IREQ_CACHE_FLUSH);
if (num_rsp < 0) {
perror("hci_inquiry");
}
for (int i = 0; i < num_rsp; ++i) {
char addr[19] = {0};
ba2str(&(ii+i)->bdaddr, addr);
addresses.push_back(addr);
}
free(ii);
ii = nullptr;
close(sock);
}
++attempts;
sleep(1);
}
// 连接蓝牙设备并发送数据
if (!addresses.empty()) {
for (const auto &address : addresses) {
int fd = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
sockaddr_rc addr{};
addr.rc_family = AF_BLUETOOTH;
addr.rc_channel = 1;
str2ba(address.c_str(), &addr.rc_bdaddr);
int status = connect(fd, reinterpret_cast<const sockaddr *>(&addr), sizeof(addr));
if (status == 0) {
std::string message = "Hello, World!";
ssize_t bytes_sent = send(fd, message.c_str(), message.length(), 0);
if (bytes_sent == -1) {
perror("send");
}
close(fd);
}
}
result = "Data sent successfully!";
} else {
result = "No Bluetooth device found.";
}
return env->NewStringUTF(result.c_str());
}
```
这段代码使用了Linux系统的socket API和BlueZ库来进行蓝牙设备的扫描和数据传输。它首先尝试多次扫描蓝牙设备,如果发现了任何设备,就尝试连接并发送数据。如果没有找到任何设备,则返回错误消息。你需要根据你的具体情况对代码进行修改和调整。
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