Question

如果特征中有多个属性，如何读取和写入值？

例如LED颜色为RGB：

特性： LED颜色UUID：7A5A0011-D04B-48EB-B3FA-32EB4F0FFAC4 RGB格式的LED颜色和强度。名称绿色名称蓝色格式无符号8位整数访问读取，写入值0 - 255格式无符号8位整数访问读取，写入值0 - 255名称红色格式化无符号8位整数访问读取，写入值0 - 255

那么如何读取/写入RGB的值？使用下面的代码我只得到一个值

if ([service.UUID isEqual:[CBUUID UUIDWithString:LED_Service_UUID]]){
        for (CBCharacteristic *aChar in service.characteristics) {
            /********* Characteristic: LED Link***************/

            NSLog(@"%@",aChar.UUID);

            if ([aChar.UUID isEqual:[CBUUID UUIDWithString: LED_CHAR_COLOR_UUID]]) {
                [peripheral readValueForCharacteristic:aChar];
                NSLog(@"%@%@%@",aChar.value,aChar.value,aChar.value);
       }

Answer 1

if ([aChar.UUID isEqual:[CBUUID UUIDWithString: LED_CHAR_COLOR_UUID]]) 
{
    _colorCharacteristic = aChar; //It's a property, save it
   [peripheral readValueForCharacteristic:aChar];
}

这应该触发委托方法：peripheral:didUpdateValueForCharacteristic:error:。

在里面，它：

if ([characteristic UUID] isEqual:[CBUUID UUIDWithString: LED_CHAR_COLOR_UUID]])
{
    NSData *valueData = [characteristic value];
}

对于每个组件（红色，绿色，蓝色，强度）：

int aComponent;
NSData *aComponentData = [valueData subdataWithRange:NSMakeRange(0, 2)]; //Range to be defined for each components
[aComponentData getBytes:&aComponent length:sizeof(aComponent)];
NSLog(@"aComponent: %d", aComponent);

然后，您可以使用UIColor从每个组件创建colorWithRed:green:blue:alpha:。

要编写，您必须再次使用NSData来查看所使用的格式。

uint8_t colorValues [] = {redValue, greenValue, blueValue, intensityValue};
NSData *data = [NSData dataWithBytes:colorValues length:sizeof(colorValues)];
[_peripheral writeValue:yourValueData forCharacteristic:_colorCharacteristic type: CBCharacteristicWriteWithResponse];` //(or  `CBCharacteristicWriteWithoutResponse` depending on the doc of your device).

BLE（蓝牙启用设备）ios

1 个答案: