Question

我即将开始开发iOS应用程序，该应用程序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Apple documentation我偶然发现了以下内容：

也就是说，外围设备管理器只支持两个密钥对象：CBAdvertisementDataLocalNameKey和 CBAdvertisementDataServiceUUIDsKey。

这是否意味着我无法指定广告的数据，而且我本质上仅限于设备名称（常量）？

我的印象是我可以根据自己的判断宣传大约28个字节的数据。如果事实证明广告自定义数据不可能，我不想开始一个重大项目。

Answer 1

答案是 - 你可以！如果您通过文档进一步阅读，您将知道如何操作。

完成阅读this和this文档后，我建议您逐行实施Central-Peripheral combo here。

以下是关于如何做到这一点（通过外围触发器peripheral:didUpdateValueForCharacteristic:在中央对应部分写入数据）的预览：

- (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;
        }
    }
}

iOS外围设备上的BLE广告数据

1 个答案: