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iOS藍牙開發(二):iOS連接外設的代碼實現

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上一篇文章介紹了藍牙的技術知識,這裡我們具體說明一下中心模式的應用場景。主設備(手機去掃描連接外設,發現外設服務和屬性,操作服務和屬性的應用。一般來說,外設(藍牙設備,比如智能手環之類的東西), 會由硬件工程師開發好,並定義好設備提供的服務,每個服務對於的特征,每個特征的屬性(只讀,只寫,通知等等),本文例子的業務場景,就是用一手機app去讀寫藍牙設備。

##ios連接外設的代碼實現流程

  1. 建立中心角色

  2. 掃描外設(discover)

  3. 連接外設(connect)

  4. 掃描外設中的服務和特征(discover)

    - 4.1 獲取外設的services

    - 4.2 獲取外設的Characteristics,獲取Characteristics的值,獲取Characteristics的Descriptor和Descriptor的值

5. 與外設做數據交互(explore and interact)

6. 訂閱Characteristic的通知

7.斷開連接(disconnect)

8.模擬器藍牙調試,慎用,最好還是用真機去調試。

##准備環境

  1. Xcode

  2. 開發證書和手機(藍牙程序需要使用使用真機調試,使用模擬器也可以調試,但是方法很蛋疼,我會放在最後說)

  3. 藍牙外設

##實現步驟

###1 導入CoreBluetooth頭文件,建立主設備管理類,設置主設備委托

#import [CoreBluetooth/CoreBluetooth.h](因識別問題,此處將尖括號改為方括號)
    @interface ViewController : UIViewController    @interface ViewController (){
        //系統藍牙設備管理對象,可以把他理解為主設備,通過他,可以去掃描和鏈接外設
        CBCentralManager *manager;
    }

    - (void)viewDidLoad {
        [super viewDidLoad];
        /*
         設置主設備的委托,CBCentralManagerDelegate
            必須實現的:
            - (void)centralManagerDidUpdateState:(CBCentralManager *)central;//主設備狀態改變的委托,在初始化CBCentralManager的適合會打開設備,只有當設備正確打開後才能使用
            其他選擇實現的委托中比較重要的:
            - (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI; //找到外設的委托
            - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral;//連接外設成功的委托
            - (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//外設連接失敗的委托
            - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//斷開外設的委托
        */
         //初始化並設置委托和線程隊列,最好一個線程的參數可以為nil,默認會就main線程
         manager = [[CBCentralManager alloc]initWithDelegate:self queue:dispatch_get_main_queue()];

###2 掃描外設(discover),掃描外設的方法我們放在centralManager成功打開的委托中,因為只有設備成功打開,才能開始掃描,否則會報錯。

-(void)centralManagerDidUpdateState:(CBCentralManager *)central{

            switch (central.state) {
                case CBCentralManagerStateUnknown:
                    NSLog(@">>>CBCentralManagerStateUnknown");
                    break;
                case CBCentralManagerStateResetting:
                    NSLog(@">>>CBCentralManagerStateResetting");
                    break;
                case CBCentralManagerStateUnsupported:
                    NSLog(@">>>CBCentralManagerStateUnsupported");
                    break;
                case CBCentralManagerStateUnauthorized:
                    NSLog(@">>>CBCentralManagerStateUnauthorized");
                    break;
                case CBCentralManagerStatePoweredOff:
                    NSLog(@">>>CBCentralManagerStatePoweredOff");
                    break;
                case CBCentralManagerStatePoweredOn:
                    NSLog(@">>>CBCentralManagerStatePoweredOn");
                    //開始掃描周圍的外設
                    /*
                     第一個參數nil就是掃描周圍所有的外設,掃描到外設後會進入
                          - (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI;
                     */
                    [manager scanForPeripheralsWithServices:nil options:nil];
                    break;
                default:
                    break;
            }

        }
        //掃描到設備會進入方法
        -(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{

            NSLog(@"當掃描到設備:%@",peripheral.name);
            //接下來可以連接設備
        }

###3 連接外設(connect)

//掃描到設備會進入方法
        -(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{
            //接下連接我們的測試設備,如果你沒有設備,可以下載一個app叫lightbule的app去模擬一個設備
            //這裡自己去設置下連接規則,我設置的是P開頭的設備
                   if ([peripheral.name hasPrefix:@"P"]){
                   /*
                       一個主設備最多能連7個外設,每個外設最多只能給一個主設備連接,連接成功,失敗,斷開會進入各自的委托
                    - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral;//連接外設成功的委托
                    - (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//外設連接失敗的委托
                    - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error;//斷開外設的委托
                    */
                    //連接設備
                   [manager connectPeripheral:peripheral options:nil];
               }
        }

        //連接到Peripherals-成功
        - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral
        {
            NSLog(@">>>連接到名稱為(%@)的設備-成功",peripheral.name);
        }

        //連接到Peripherals-失敗
        -(void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
        {
            NSLog(@">>>連接到名稱為(%@)的設備-失敗,原因:%@",[peripheral name],[error localizedDescription]);
        }

        //Peripherals斷開連接
        - (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error{
            NSLog(@">>>外設連接斷開連接 %@: %@\n", [peripheral name], [error localizedDescription]);

        }

###4 掃描外設中的服務和特征(discover)

設備連接成功後,就可以掃描設備的服務了,同樣是通過委托形式,掃描到結果後會進入委托方法。但是這個委托已經不再是主設備的委托(CBCentralManagerDelegate),而是外設的委托(CBPeripheralDelegate),這個委托包含了主設備與外設交互的許多 回叫方法,包括獲取services,獲取characteristics,獲取characteristics的值,獲取characteristics的Descriptor,和Descriptor的值,寫數據,讀rssi,用通知的方式訂閱數據等等。

4.1獲取外設的services

//連接到Peripherals-成功
        - (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral
        {
            NSLog(@">>>連接到名稱為(%@)的設備-成功",peripheral.name);
            //設置的peripheral委托CBPeripheralDelegate
            //@interface ViewController : UIViewController            [peripheral setDelegate:self];
            //掃描外設Services,成功後會進入方法:-(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{
            [peripheral discoverServices:nil];

        }
        //掃描到Services
        -(void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error{
            //  NSLog(@">>>掃描到服務:%@",peripheral.services);
            if (error)
            {
                NSLog(@">>>Discovered services for %@ with error: %@", peripheral.name, [error localizedDescription]);
                return;
            }

            for (CBService *service in peripheral.services) {
                             NSLog(@"%@",service.UUID);
                             //掃描每個service的Characteristics,掃描到後會進入方法: -(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
                             [peripheral discoverCharacteristics:nil forService:service];
                         }

        }

4.2獲取外設的Characteristics,獲取Characteristics的值,獲取Characteristics的Descriptor和Descriptor的值

//掃描到Characteristics
     -(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{
         if (error)
         {
             NSLog(@"error Discovered characteristics for %@ with error: %@", service.UUID, [error localizedDescription]);
             return;
         }

         for (CBCharacteristic *characteristic in service.characteristics)
         {
             NSLog(@"service:%@ 的 Characteristic: %@",service.UUID,characteristic.UUID);
         }

         //獲取Characteristic的值,讀到數據會進入方法:-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
         for (CBCharacteristic *characteristic in service.characteristics){
             {
                 [peripheral readValueForCharacteristic:characteristic];
             }
         }

         //搜索Characteristic的Descriptors,讀到數據會進入方法:-(void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
         for (CBCharacteristic *characteristic in service.characteristics){
             [peripheral discoverDescriptorsForCharacteristic:characteristic];
         }


     }

    //獲取的charateristic的值
    -(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
        //打印出characteristic的UUID和值
        //!注意,value的類型是NSData,具體開發時,會根據外設協議制定的方式去解析數據
        NSLog(@"characteristic uuid:%@  value:%@",characteristic.UUID,characteristic.value);

    }

    //搜索到Characteristic的Descriptors
    -(void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{

        //打印出Characteristic和他的Descriptors
         NSLog(@"characteristic uuid:%@",characteristic.UUID);
        for (CBDescriptor *d in characteristic.descriptors) {
            NSLog(@"Descriptor uuid:%@",d.UUID);
        }

    }
    //獲取到Descriptors的值
    -(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForDescriptor:(CBDescriptor *)descriptor error:(NSError *)error{
        //打印出DescriptorsUUID 和value
        //這個descriptor都是對於characteristic的描述,一般都是字符串,所以這裡我們轉換成字符串去解析
        NSLog(@"characteristic uuid:%@  value:%@",[NSString stringWithFormat:@"%@",descriptor.UUID],descriptor.value);
    }

###5 把數據寫到Characteristic中

//寫數據
    -(void)writeCharacteristic:(CBPeripheral *)peripheral
                characteristic:(CBCharacteristic *)characteristic
                         value:(NSData *)value{

        //打印出 characteristic 的權限,可以看到有很多種,這是一個NS_OPTIONS,就是可以同時用於好幾個值,常見的有read,write,notify,indicate,知知道這幾個基本就夠用了,前連個是讀寫權限,後兩個都是通知,兩種不同的通知方式。
        /*
         typedef NS_OPTIONS(NSUInteger, CBCharacteristicProperties) {
         CBCharacteristicPropertyBroadcast= 0x01,
         CBCharacteristicPropertyRead= 0x02,
         CBCharacteristicPropertyWriteWithoutResponse= 0x04,
         CBCharacteristicPropertyWrite= 0x08,
         CBCharacteristicPropertyNotify= 0x10,
         CBCharacteristicPropertyIndicate= 0x20,
         CBCharacteristicPropertyAuthenticatedSignedWrites= 0x40,
         CBCharacteristicPropertyExtendedProperties= 0x80,
         CBCharacteristicPropertyNotifyEncryptionRequired NS_ENUM_AVAILABLE(NA, 6_0)= 0x100,
         CBCharacteristicPropertyIndicateEncryptionRequired NS_ENUM_AVAILABLE(NA, 6_0)= 0x200
         };

         */
        NSLog(@"%lu", (unsigned long)characteristic.properties);


        //只有 characteristic.properties 有write的權限才可以寫
        if(characteristic.properties & CBCharacteristicPropertyWrite){
            /*
                最好一個type參數可以為CBCharacteristicWriteWithResponse或type:CBCharacteristicWriteWithResponse,區別是是否會有反饋
            */
            [peripheral writeValue:value forCharacteristic:characteristic type:CBCharacteristicWriteWithResponse];
        }else{
            NSLog(@"該字段不可寫!");
        }


    }

###6 訂閱Characteristic的通知

    //設置通知
    -(void)notifyCharacteristic:(CBPeripheral *)peripheral
                characteristic:(CBCharacteristic *)characteristic{
        //設置通知,數據通知會進入:didUpdateValueForCharacteristic方法
        [peripheral setNotifyValue:YES forCharacteristic:characteristic];

    }

    //取消通知
    -(void)cancelNotifyCharacteristic:(CBPeripheral *)peripheral
                 characteristic:(CBCharacteristic *)characteristic{

         [peripheral setNotifyValue:NO forCharacteristic:characteristic];
    }

###7 斷開連接(disconnect)

//停止掃描並斷開連接
    -(void)disconnectPeripheral:(CBCentralManager *)centralManager
                     peripheral:(CBPeripheral *)peripheral{
        //停止掃描
        [centralManager stopScan];
        //斷開連接
        [centralManager cancelPeripheralConnection:peripheral];
    }

###8 模擬器藍牙調試,慎用,最好還是用真機去調試。

由於在iPhone 4s之後的iOS才支持BLE,新一代的這些iOS設備又都不便宜,在做測試的時候,用iOS模擬器進行調試,可以節約一些開發成本。怎麼在iOS模擬器上調試BLE,

蘋果最初給出的說明是,支持BLE的mac機子上可以用模擬器進行調試,並給出了一份技術文檔(傳送門),惡心的是,後來蘋果抽風,又把這份文檔移除,並且把iOS 7.0的模擬器上對BLE的支持也移除掉了(難道是想讓大家多買設備測試?Apple sucks.)後面,網上搜了一下,解決辦法如下:

1. 買一個CSR藍牙4.0 USB適配器(某寶上大概30塊錢),在機子上插入該物(你懂的)

2. 在Terminal下敲入sudo nvram bluetoothHostControllerSwitchBehavior="never" , 重啟Mac。

3. 用XCode 4.6調試代碼,在iOS 6.1的模擬器上跑程序(用XCode 5.0跑iOS 7.0模擬器會拋異常,原因上面詳訴過了,Apple sucks,你懂的)

如何降低模擬器的IOS版本呢?

XCode->Preferences->Downloads裡面有很多simulators你可以下載

選擇個6.1的下載好了

代碼下載

我博客中大部分示例代碼都上傳到了github,地址是:https://github.com/coolnameismy/demo,點擊跳轉代碼下載地址

本文代碼存放目錄是BleDemo

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