Slider
The slider varies the datastream value between the datastream’s min/max values based on the slider’s horizontal position. It is similar in the way a potentiometer is used to vary resistance based on its position.
Datastream
Select or create a datastream of data type integer or double. Widget properties (label, color, etc.) are also changed via the datastream, but only for virtual, enumerable, and location pins, not digital and analog pins.
Widget Controls
The widget has the following controls:
Send on release: Enable to limit updating the assigned datastream value only when the control is released by the user.
How to process widget input on the device
When the control is pressed, value is sent and stored into the Blynk.Cloud. After that it's sent to your device.
Reading the widget value
For example, if Slider widget is set to Datastream with Virtual Pin V1, you can use such code:
Changing the datastream value
You can update the assigned datastream value using the hardware or HTTP API.
Hardware:
HTTP API:
Don't put Blynk.virtualWrite()
into the void loop()
as it can cause a flood of messages and your hardware will be disconnected. Send such updates only when necessary, use flags, or timers.
Change Widget Properties
You can change certain properties of the Widget from your hardware. For that, use this command:
Where:
vPin
is: virtual pin number the widget is assigned towidgetProperty
: property you want to changepropertyValue
: value of the property you want to change
Don't put Blynk.setProperty()
into the void loop()
as it can cause a flood of messages and your hardware will be disconnected. Send such updates only when necessary, or use timers.
Properties you can change
You can change the properties color, label, isDisabled, isHidden of the widget from your hardware, or via an HTTP API. The color hexadecimal values in the HTTP API URL must include the hash # character urlencoded as %23.
Set a custom label for the widget
Show/Hide
Widget will be hidden from dashboard. Design your UI so that it doesn't look weird when there is no widget.
Disable/Enable
Widget will be greyed out on UI and users won't be able to tap on it.
Set a color for the widget
Change widget properties via HTTPs API
Updates the Datastream Property and all assigned Widgets
GET
https://{server_address}/external/api/update/property?token={your 32 char token}&pin={your vPin}&{property}={value}
The endpoint allows you to update the Datastream Property value via GET request. All widgets (both web and mobile) that are assigned to this datastream will inherit this property. The Datastream Property is persistent and will be stored forever until you change it with another value. In order to clear the property you need to clear the device data in device actions menu.
Example:
https://blynk.cloud/external/api/update/property?token=GVki9IC70vb3IqvsV0YD3el4y0OpneL1&pin=V2&label=My%20Label
https://blynk.cloud/external/api/update/property?token=GVki9IC70vb3IqvsV0YD3el4y0OpneL1&pin=V1&color=%23D3435C
https://blynk.cloud/external/api/update/property?token=GVki9IC70vb3IqvsV0YD3el4y0OpneL1&pin=V1&isDisabled=true
Path Parameters
Name | Type | Description |
---|---|---|
{server address}* | string | Get from the bottom right of your Blynk console. More information. |
Query Parameters
Name | Type | Description |
---|---|---|
token* | string | Device auth token from Device info |
pin* | string | The datastream virtual pin (should start with "v") |
{property} | string | The property of the widget you want to update: |
label | string | the text used as widget label |
isDisabled | string | true or false |
isHidden | string | true or false |
color | string | color hexadecimal, must include the hash # character urlencoded as %23 |
Sync to the latest known state
You can update your hardware to the latest datastream value from Blynk.Cloud after your hardware went offline, and then came online again. Use Blynk.syncVirtual()
to update a single virtual pin, or Blynk.syncAll()
to update all virtual pins. See State Syncing for more details.
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