从BLE设备读取数据 [英] Read data from BLE device
问题描述
我正在尝试从蓝牙设备（BR-LE4.0-S2）读取数据。我能够连接BLE设备，但无法从中读取数据。我没有任何关于BLE服务及其特性的规范。这里我的问题是 - （void）peripheral：didUpdateValueForCharacteristic：error：没有被调用。我按照教程 https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/PerformingCommonCentralRoleTasks/ PerformingCommonCentralRoleTasks.html＃// apple_ref / doc / uid / TP40013257-CH3-SW2 。以下是我的代码。
I am trying to read data from a bluetooth device (BR-LE4.0-S2). I was able to connect BLE device, but not able to read data from it.I don't have any specification about BLE services and it's characteristics. Here what my issue is - (void)peripheral:didUpdateValueForCharacteristic:error: not getting called. I followed tutorial "https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/PerformingCommonCentralRoleTasks/PerformingCommonCentralRoleTasks.html#//apple_ref/doc/uid/TP40013257-CH3-SW2" .Following is my code.
我的要求是读取数据从BLE设备不断。非常感谢任何帮助。
What my requirement is to read data continuously from BLE device. Any help is greatly appreciated.
- (void)viewDidLoad
{
self.myCentralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
self.peripheral = [[CBPeripheral alloc] init];
self.peripheral.delegate = self;
[super viewDidLoad];
}
- (void) centralManagerDidUpdateState:(CBCentralManager *)central {
switch (central.state) {
case CBCentralManagerStatePoweredOn:
[self.myCentralManager scanForPeripheralsWithServices:nil options:nil];
break;
default:
NSLog(@"Central Manager did change state");
break;
}
}
- (void)centralManager:(CBCentralManager *)central
didDiscoverPeripheral:(CBPeripheral *)peripheral
advertisementData:(NSDictionary *)advertisementData
RSSI:(NSNumber *)RSSI {
NSLog(@"Discovered %@", peripheral.name);
[self.myCentralManager stopScan];
NSLog(@"Scanning stopped");
if (self.peripheral != peripheral) {
self.peripheral = peripheral;
NSLog(@"Connecting to peripheral %@", peripheral);
// Connects to the discovered peripheral
[self.myCentralManager connectPeripheral:peripheral options:nil];
}
}
- (void)centralManager:(CBCentralManager *)central
didConnectPeripheral:(CBPeripheral *)peripheral {
NSLog(@"Peripheral connected");
NSLog(@"Peripheral services : %@",peripheral.services );
[self.peripheral setDelegate:self];
[peripheral discoverServices:nil];
}
- (void)peripheral:(CBPeripheral *)peripheral
didDiscoverServices:(NSError *)error {
if (error) {
NSLog(@"Error discovering service: %@", [error localizedDescription]);
return;
}
for (CBService *service in peripheral.services) {
[peripheral discoverCharacteristics:nil forService:nil];
}
}
- (void)peripheral:(CBPeripheral *)peripheral
didDiscoverCharacteristicsForService:(CBService *)service
error:(NSError *)error {
int i = 0;
for (CBCharacteristic *characteristic in service.characteristics) {
[peripheral setNotifyValue:YES forCharacteristic: characteristic];
}
}
- (void)peripheral:(CBPeripheral *)peripheral
didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic
error:(NSError *)error {
NSData *data = characteristic.value;
NSString *value = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];
NSLog(@"Value %@",value);
NSString *stringFromData = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(@"Data ====== %@", stringFromData);
}
- (void)peripheral:(CBPeripheral *)peripheral
didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic
error:(NSError *)error {
if (error) {
NSLog(@"Error changing notification state: %@",
[error localizedDescription]);
}
NSString *value = [[NSString alloc] initWithData:self.interestingCharacteristic.value encoding:NSUTF8StringEncoding];
NSLog(@"Value %@",value);
NSLog(@"description: %@, descriptors: %@, properties: %d, service :%@, value:%@", characteristic.description, characteristic.descriptors, characteristic.properties, characteristic.service, characteristic.value);
NSData *data = characteristic.value;
if (characteristic.isNotifying) {
NSString *stringFromData = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
[peripheral readValueForCharacteristic:characteristic];
NSLog(@"Data ====== %@", @"ccdc");
} else {
[self.myCentralManager cancelPeripheralConnection:peripheral];
}
}
- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
{
NSLog(@"Peripheral Disconnected");
self.peripheral = nil;
// We're disconnected, so start scanning again
NSDictionary *scanOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO] forKey:CBCentralManagerScanOptionAllowDuplicatesKey];
[self.myCentralManager scanForPeripheralsWithServices:nil options:scanOptions];
}
推荐答案
从a读取值BLE外围设备，请按照以下步骤操作
To read a value from a BLE peripheral device, follow these steps
-
扫描可用设备
Scan for avilable devices
NSDictionary *options = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:CBCentralManagerScanOptionAllowDuplicatesKey];
[self.myCentralManager scanForPeripheralsWithServices:nil options:options];`
On检测到一个设备，将回到didDiscoverPeripheral委托方法。然后与检测到的BLE设备建立连接
On detecting a device, will get a call back to "didDiscoverPeripheral" delegate method. Then establish a connection with detected BLE device
-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {
//Connect detected device....
if (!peripheral.isConnected) {
peripheral.delegate = self;
[bluetoothManager_ connectPeripheral:peripheral options:nil];
}
}
成功连接后，请求BLE设备中提供的所有服务
On successful connection, request for all the services available in the BLE device
- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{
NSLog(@"Peripheral Connected");
// Make sure we get the discovery callbacks
peripheral.delegate = self;
// Search only for services that match our UUID
[peripheral discoverServices:nil];
}
请求每项服务中可用的所有特征
Request all the characteristics available in each services
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {
if (error) {
NSLog(@"Error discovering services: %@", [error localizedDescription]);
return;
}
// Loop through the newly filled peripheral.services array, just in case there's more than one.
for (CBService *service in peripheral.services) {
[peripheral discoverCharacteristics:nil forService:service];
}
}
获得所需的特征细节后，我们需要订阅它，这让外围设备知道我们想要它包含的数据
Once we get the required characteristics detail, we need to subscribe to it, which lets the peripheral know we want the data it contains
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{
// Deal with errors (if any)
if (error) {
NSLog(@"Error discovering characteristics: %@", [error localizedDescription]);
return;
}
// Again, we loop through the array, just in case.
for (CBCharacteristic *characteristic in service.characteristics) {
if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:REQUIRED_CHARA_ID]]) {
// If it is, subscribe to it
[peripheral setNotifyValue:YES forCharacteristic:characteristic];
}
}
}
完成所有这些步骤，BLE设备将通过委托方法通知您通知状态更改
Completing all these steps, BLE device will let you know the notification status change through delegate method
- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
if (error) {
NSLog(@"Error changing notification state: %@", error.localizedDescription);
}
// Notification has started
if (characteristic.isNotifying) {
NSLog(@"Notification began on %@", characteristic);
}
}
您将通过以下方法接收来自BLE设备的任何通知
You will recieve any notification from BLE device in the following method
- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
if (error) {
NSLog(@"Error reading characteristics: %@", [error localizedDescription]);
return;
}
if (characteristic.value != nil) {
//value here.
}
}
这篇关于从BLE设备读取数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
