iOS外围设备上的广告数据

Question

我即将开始开发一个iOS应用程序，它依赖于能够通过蓝牙LE广告发送小块数据(因此iOS设备是外围设备)。

阅读以下苹果文档时，我无意中发现了以下内容：

也就是说，外围管理器对象只支持两个键: CBAdvertisementDataLocalNameKey和CBAdvertisementDataServiceUUIDsKey。

这是否意味着我无法具体说明所宣传的数据，并且基本上仅限于设备名称(常量)？

我给人的印象是，我可以随意为大约28字节的数据做广告。如果广告定制数据是不可能的，我不想开始一个重大项目。

Answer 1

答案是-你可以！如果你进一步阅读文档，你就会知道如何去做。

阅读完这和这文档之后，我建议您逐行查看中央-外围组合这里的实现。

下面简要介绍一下如何做到这一点(通过外围触发器在中央对应的peripheral:didUpdateValueForCharacteristic:上编写数据)：

- (void)peripheralManager:(CBPeripheralManager *)peripheral central:(CBCentral *)central didSubscribeToCharacteristic:(CBCharacteristic *)characteristic {

    _dataToSend = [_textView.text dataUsingEncoding:NSUTF8StringEncoding];

    _sendDataIndex = 0;

    [self sendData];
}

- (void)sendData {

    static BOOL sendingEOM = NO;

    // end of message?
    if (sendingEOM) {
        BOOL didSend = [self.peripheralManager updateValue:[@"EOM" dataUsingEncoding:NSUTF8StringEncoding] forCharacteristic:self.transferCharacteristic onSubscribedCentrals:nil];

        if (didSend) {
            // It did, so mark it as sent
            sendingEOM = NO;
        }
        // didn't send, so we'll exit and wait for peripheralManagerIsReadyToUpdateSubscribers to call sendData again
        return;
    }

    // We're sending data
    // Is there any left to send?
    if (self.sendDataIndex >= self.dataToSend.length) {
        // No data left.  Do nothing
        return;
    }

    // There's data left, so send until the callback fails, or we're done.
    BOOL didSend = YES;

    while (didSend) {
        // Work out how big it should be
        NSInteger amountToSend = self.dataToSend.length - self.sendDataIndex;

        // Can't be longer than 20 bytes
        if (amountToSend > NOTIFY_MTU) amountToSend = NOTIFY_MTU;

        // Copy out the data we want
        NSData *chunk = [NSData dataWithBytes:self.dataToSend.bytes+self.sendDataIndex length:amountToSend];

        didSend = [self.peripheralManager updateValue:chunk forCharacteristic:self.transferCharacteristic onSubscribedCentrals:nil];

        // If it didn't work, drop out and wait for the callback
        if (!didSend) {
            return;
        }

        NSString *stringFromData = [[NSString alloc] initWithData:chunk encoding:NSUTF8StringEncoding];
        NSLog(@"Sent: %@", stringFromData);

        // It did send, so update our index
        self.sendDataIndex += amountToSend;

        // Was it the last one?
        if (self.sendDataIndex >= self.dataToSend.length) {

            // Set this so if the send fails, we'll send it next time
            sendingEOM = YES;

            BOOL eomSent = [self.peripheralManager updateValue:[@"EOM" dataUsingEncoding:NSUTF8StringEncoding] forCharacteristic:self.transferCharacteristic onSubscribedCentrals:nil];

            if (eomSent) {
                // It sent, we're all done
                sendingEOM = NO;
                NSLog(@"Sent: EOM");
            }

            return;
        }
    }
}