Menu

Creates a list of two or more text labeled menu items for the user to choose from. When the menu is tapped by the user, the list is displayed full screen in the app, displaying up to 11 menu items. More than 11 menu items may be accessed by scrolling the list. When the user taps a menu item, the zero based index is assigned to the assigned integer/enum datastream. The order of the menu items can be easily changed by dragging them vertically. Delete menu items by swiping them to the right.

Datastream

Select or create a datastream of data type integer or enumerable.

Widget Controls

The widget controls are solely the menu items. If the number of items exceeds the page height, then the page can be scrolled vertically.

How to process widget with the hardware

When the menu item is pressed, value is sent and stored into the Blynk.Cloud. After that it's sent to your device.

Reading the widget value(s)

Example code:

BLYNK_WRITE {
  switch (param.asInt()) {
    case 0: { // Item 1
      Serial.println("Item 1 selected");
      break;
    }
    case 1: { // Item 2
      Serial.println("Item 2 selected");
      break;
    }    
  }
}

Changing button state

You can change the value of the datastream assigned to the widget with hardware or HTTP API. For a datastream V5 assigned data type of integer or enumerable, the following will change the option selection to the second (index = 1):

Hardware:

Blynk.virtualWrite(V5, 1);

HTTP API:

https://{server_address}/external/api/update/?token={your 32 char token}&V5=1

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.

Sketch: Menu

Change Widget Properties

You can change certain properties of the Widget from your hardware. For that, use this command:

Blynk.setProperty(vPin, "widgetProperty", "propertyValue"); 

Where:

  • vPin is: virtual pin number the widget is assigned to

  • widgetProperty: property you want to change

  • propertyValue: 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 label, color, isDisabled, isHidden of the widget from your hardware, or via an HTTP API. The URL must be encoded, so spaces in labels must be replaced with %20, and color hexadecimal values in the HTTP API URL must include the hash # character urlencoded as %23.

Change Widget Label

Blynk.setProperty(V1, "label", "Air temperature");

Set Widget Color

//#D3435C - Blynk RED 
Blynk.setProperty(V1, "color", "#D3435C");

Disable/Enable

Widget will be greyed out on UI and users won't be able to tap on it.

Blynk.setProperty(V1, "isDisabled", true);

Show/Hide

Widget will be hidden from dashboard. Design your UI so that it doesn't look weird when there is no widget.

Blynk.setProperty(V1, "isHidden", true);

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

Query Parameters

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.

BLYNK_CONNECTED() { 
  // Called when hardware is connected to Blynk.Cloud  

  // get the latest value for V1
  Blynk.syncVirtual(V1); 

  // Request Blynk server to re-send latest values for all pins
  Blynk.syncAll()
}

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