# wx.readBLECharacteristicValue(Object object)

Start from base library version 1.1.0. Please remaining backward compatible.

with Promise style call: Supported

Mini Program plugin: Support, need to Mini Program base library version no less than 1.9.6

Reads the binary data of the characteristic value of a Bluetooth low-power device. Note: Features of the device must support read Before it can be successfully invoked.

# parameter

# Object object

attribute	type	Required	Introductions
deviceId	string	yes	Bluetooth Device id
serviceId	string	yes	Bluetooth Feature Corresponding Service UUID
characteristicId	string	yes	Bluetooth characteristic UUID
success	function	no	Interface calls the successful callback function
fail	function	no	Interface calls failed callback functions
complete	function	no	Callback function at the end of an interface call (both successful and unsuccessful calls are executed)

# error

Error code	Error message	Introductions
0	ok	normal
-1	already connect	Connected
10000	not init	Uninitialized Bluetooth adapter
10001	not available	The current Bluetooth adapter is not available
10002	No device	Specified device not found
10003	connection fail	Connection failure
10004	No service	Specified service not found
10005	No characteristic	Did not find the specified signature.
10006	No connection	Current connection disconnected
10007	property not support	Current feature does not support this operation
10008	system error	All other system reported anomalies
10009	system not support	Android System specific, system version below 4.3 Not supported WAS
10012	operate time out	Connection Timeout
10013	invalid_data	Connect deviceId Is empty or incorrectly formatted

# Be careful

Multiple parallel calls have the possibility of read failure.
The information read by the interface needs to be stored in the wx.onBLECharacteristicValueChange Method to get the callback registered with the.

# sample code

Preview with Developer Tool

// Must be here to get a callback
wx.onBLECharacteristicValueChange(function(characteristic) {
  console.log('characteristic value comed:', characteristic)
})

wx.readBLECharacteristicValue({
  // Here. deviceId Need has passed createBLEConnection Establish a link with the corresponding device
  deviceId,
  // Here. serviceId Need to getBLEDeviceServices Get in interface
  serviceId,
  // Here. characteristicId Need to getBLEDeviceCharacteristics Get in interface
  characteristicId,
  success (res) {
    console.log('readBLECharacteristicValue:', res.errCode)
  }
})