Image List

The Alexa image list template (AlexaImageList) displays a scrolling list of images and text. AlexaImageList is a full-screen template that optionally displays a header, footer, and background. You provide a set of image-based items to display in the list and configure the appearance of the list, such as including dividers and whether to number the items. You can also provide the command to run when a user selects an item from the list.

Import the alexa-layouts package

To use AlexaImageList, import the alexa-layouts package.

The latest version of the alexa-layouts package is 1.4.0. AlexaImageList was introduced in version 1.1.0.

AlexaImageList parameters

All parameters except type are optional.

Name Type Default Description Version added/updated

backgroundAlign

String

center

Image/video alignment to apply to background image/video.

1.1.0

backgroundBlur

Boolean

false

When true, display the provided background image with a blur effect. Applies when backgroundImageSource contains a value.

1.1.0

backgroundColor

Color

None

Color to use as a background color. Used when neither backgroundImageSource or backgroundVideoSource contain values.

1.1.0

backgroundColorOverlay

Boolean

false

When true, apply a scrim to the background to make it easier to read the text displayed over the image or video.

1.1.0

backgroundImageSource

String

None

URL for the background image source. Used when backgroundVideoSource isn't provided.

1.1.0

backgroundOverlayGradient

Boolean

false

When true, apply a gradient to the background.

1.1.0

backgroundScale

String

best-fill

Image or video scaling to apply to background image or video.

1.1.0

backgroundVideoSource

Video source

None

The background video source. Provide a source in the same format shown for the source property of the Video component

1.1.0

defaultImageSource

String

URL for a default image to use for any list items that don't have an imageSource defined. Provide a defaultImageSource to to make sure that image containers are never empty. The same defaultImageSource is used for all list items that are missing imageSource.

1.1.0

entities

Array

[]

Array of entity data to bind to this template.

1.2.0

headerAttributionImage

String

None

URL for attribution image source. Displays when headerAttributionPrimacy is true, or on a device that shows Title/Subtitle and Attribution.

1.1.0

headerAttributionOpacity

Number

0.8

The opacity of the attribution text and attribution image in the header. Set to a number between 0 and 1.

1.3.0

headerAttributionPrimacy

Boolean

true

When true, display the headerAttributionImage on devices that display a single element due to screen size. When false, display the headerTitle and headerSubtitle.

1.1.0

headerAttributionText

String

None

Attribution text to render in the header. Shown only when no headerAttributionImage is provided and headerAttributionPrimacy is true, or on a device that shows both Title/Subtitle and Attribution.

1.1.0

headerBackButton

Boolean

false

When true, displays a back button in the header. Set the headerBackButtonCommand property to specify a command to run when the user clicks this button.

1.1.0

headerBackButtonAccessibilityLabel

String

None

An accessibility label to describe the back button to customers who use a screen reader.

1.1.0

headerBackButtonCommand

Command

{"type":"SendEvent","arguments":["goBack"]}

Command to run when the user selects the back button.

1.1.0

headerBackgroundColor

String

transparent

Optional color value to use as the background color for the Header.

1.1.0

headerDivider

Boolean

false

When true, display a divider below the header to help separate it from the content.

1.1.0

headerTitle

String

None

Primary text to render in header.

1.1.0

hideOrdinal

Boolean

false

When true, don't display the number next to each list item.

1.1.0

hintText

String

None

Hint text to display in the footer. Use textToHint to add the correct wake word to the hint. Not shown on small devices unless imageMetadataPrimacy is false.

1.1.0

imageAlignment

String

center

Sets a default for the imageAlignment option for the items in listItems. See the imageAlignment property in AlexaImageListItem.

1.1.0

imageAspectRatio

String

square

Aspect ratio to use for the image bounding box for all the items in the list. Options are square, round, standard_landscape, standard_portrait, poster_landscape, poster_portrait, widescreen. This property works the same as the imageAspectRatio property for the AlexaImage responsive component except that the height and width of the bounding box are pre-defined based on the aspect ratio and can't be changed. All list items always use the same aspect ratio.

1.1.0

imageBlurredBackground

Boolean

false

Sets a default for the imageBlurredBackground option for the items in listItems. See the imageBlurredBackground property in AlexaImageListItem.

1.1.0

imageHeight

Dimension

none

Sets a default for the imageHeight option for the items in listItems. Each image in the list scales to fit within this height using the imageScale setting.

1.4.0

imageHideScrim

Boolean

false

Sets a default for the imageHideScrim option for the items in listItems. See the imageHideScrim property in AlexaImageListItem.

1.1.0

imageMetadataPrimacy

Boolean

true

When true, hide the hintText on small devices and display the secondaryText and tertiaryText. Set this property to false to hide the secondaryText and tertiaryText and display the hintText instead. This property is ignored on larger devices that have room to display both the text items and the hintText.

1.1.0

imageRoundedCorner

Boolean

true

Sets a default for the imageRoundedCorner option for the items in listItems. See the imageRoundedCorner property in AlexaImageListItem.

1.1.0

imageScale

String

best-fit

Sets a default for the imageScale option for the items in listItems. See the imageScale property in AlexaImageListItem.

1.1.0

imageShadow

boolean

true

Sets a default for the imageShadow option for the items in listItems. When true, display a drop shadow behind the image for each list item.

1.3.0

lang

String

""

The language for the text displayed in the template. This language determines the default font used for the text. For example, when set to ar-SA, the component uses Arabic fonts when available on the device. Set to a BCP-47 string.

For more about langauge-specific fonts for responsive components, see Language-specific fonts in the components and templates.

1.4.0

layoutDirection

String

LTR

Specifies the layout direction for the content. Set this property to either LTR (left-to-right) or RTL (right-to-left). This property doesn't inherit the layoutDirection from the component's parent container. Therefore, explicitly set this property when needed.

For more about support for right-to-left languages in the responsive components, see Support for Right-to-left Languages.

1.4.0

listId

String

An identifier to assign to the Sequence component used for the list. Set listId to a value to enable voice-based scrolling with the built-in intents. Also set this parameter to an ID if you need to target the list for commands, such as the SpeakList command.

1.2.0

listItems

Array of AlexaImageListItem

An array of items to display in the list. Each item is an object with the same properties as defined in AlexaImageListItem. See Provide the list items.

1.1.0

primaryAction

Command

none

Sets a default for the primaryAction option for the items in listItems. Set this property to the command to trigger when the user selects an item from the list. See the primaryAction property in AlexaImageListItem.

1.1.0

speechItems

any

[]

An array of speech items. The AlexaImageList template assigns each item in this array to the speech property of the corresponding list item. Use this property when you want to use the SpeakList command to speak the list items. For details, see Use the SpeakList command with AlexaImageList.

1.2.0

theme

String

dark

Set the dark or light color theme. The selected theme controls the colors used for the template.

1.1.0

type

String

None

Always set to AlexaImageList

1.1.0

videoAudioTrack

String

foreground

Audio track to play on when playing the video. Can be foreground | background | none

1.1.0

videoAutoPlay

Boolean

false

When true, the video begins playing automatically when the document renders on the device. Applies when backgroundVideoSource contains a value.

1.1.0

Provide the list items

The AlexaImageList template expects an array of items in the listItems property. Each item is an object with the same properties as those defined in the AlexaImageListItem responsive component.

The following example illustrates an array of items in a data source called imageListData.

{
  "imageListData": {
    "listItemsToShow": [
      {
        "primaryText": "First list item",
        "secondaryText": "Secondary text",
        "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/md_gruyere.png",
        "imageProgressBarPercentage": 90,
        "imageShowProgressBar": false,
        "ratingSlotMode": "multiple",
        "ratingNumber": 2.87,
        "ratingText": "(206 ratings)"
      },
      {
        "primaryText": "Second list item",
        "secondaryText": "Secondary Text",
        "tertiaryText": "Tertiary text",
        "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/md_gorgonzola.png",
        "providerText": "Provider Text",
        "imageProgressBarPercentage": 50,
        "ratingSlotMode": "multiple",
        "ratingNumber": 4.5,
        "ratingText": "(500 ratings)"
      },
      {
        "primaryText": "No image, use the default",
        "secondaryText": "Secondary text",
        "ratingSlotMode": "multiple",
        "ratingNumber": 2,
        "ratingText": "(50 ratings)"
      },
      {
        "primaryText": "Fourth list item",
        "secondaryText": "No progress bar",
        "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/tl_brie.png",
        "ratingSlotMode": "multiple",
        "ratingNumber": 5,
        "ratingText": "(452 ratings)"
      },
      {
        "primaryText": "Fifth list item",
        "secondaryText": "With background blur",
        "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/MollyforBT7.png",
        "ratingSlotMode": "multiple",
        "ratingNumber": 0,
        "ratingText": "(206 ratings)"
      },
      {
        "primaryText": "Sixth list item (long text that wraps)",
        "secondaryText": "Longer secondary text that truncates",
        "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/sm_blue.png",
        "ratingSlotMode": "multiple",
        "ratingNumber": 0,
        "ratingText": "(206 ratings)"
      }
    ]
  }
}

Then, bind this array to the listItems property with the expression ${imageListData.listItemsToShow}.

{
  "type": "AlexaImageList",
  "listItems": "${imageListData.listItemsToShow}",
  "defaultImageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/BT7_Background.png",
  "imageBlurredBackground": true,
  "primaryAction": {
    "type": "SendEvent",
    "arguments": [
      "ListItemSelected",
      "${ordinal}"
    ]
  }
}

The specific list item parameters available depend on the version of AlexaImageListItem. For example, the properties to display a rating require the 1.2.0 or later version of the alexa-layouts package. For the full set of properties, see AlexaImageListItem.

Set defaults for the list items

The AlexaImageList template includes properties that correspond to properties in AlexaImageListItem. Use these to set default values for those properties.

There are two types of defaults:

  • Defaults you can set or override for an individual item – AlexaImageList uses the value provided on the individual item when available, and uses the value provided on AlexaImageList otherwise.

    For example, you might set imageScale to best-fit for the whole list, but then override it to best-fill for one item on the list.

  • Defaults that always apply to all the items in the list – AlexaImageList always uses the value provided on AlexaImageList for these properties. Any value in a corresponding property on an individual item is ignored.

    For example, you must set imageAspectRatio on the whole list. You can't have a list in which some items display as squares and some as circles. Any value for imageAspectRatio on a list item is ignored.

The following table lists the properties you use as defaults.

Property Can override on an item
defaultImageSource No
imageAlignment Yes
imageAspectRatio No
imageBlurredBackground Yes
imageHeight No
imageHideScrim Yes
ImageMetadataPrimacy No
imageRoundedCorner Yes
imageScale Yes
imageShadow Yes
primaryAction Yes

For details about each of these properties, see AlexaImageListItem.

Specify the action for each list item

AlexaImageList is interactive. Users can select items on the list. Set the primaryAction property to the command you want to run when the user selects an item.

When you set primaryAction on the AlexaImageList component, AlexaImageList passes the command to each item on the list.

To override command for an individual list item, set the primaryAction property on the list item itself.

The following example shows how you to use the SendEvent command to send your skill a UserEvent request. This passes the number representing the selected item as part of the SendEvent.arguments array.

{
  "primaryAction": {
    "type": "SendEvent",
    "arguments": [
      "ListItemSelected",
      "${ordinal}"
    ]
  }
}

Use the SpeakList command with AlexaImageList

Use the speechItems parameter on AlexaImageList when you want to use the SpeakList command to read the list of items. Set the speechItems property to an array of items.

The SpeakList command requires a speech property on each list item to speak. The speech property must be set to the output of either the ssmlToSpeech or textToSpeech transformer. Therefore, you need to do the following to use SpeakList with AlexaImageList:

  • Use an object type data source for the array of items to speak. Within this data source, configure either the ssmlToSpeech or textToSpeech transformer to process the array of items to speak.
  • Bind the speechItems property of the AlexaImageList to list of items to speak.
  • Invoke the SpeakList command for the list.

Configure a data source for list speech items

  1. Create an object type data source to use with your document.

  2. In the data source, add an array of items to speak to a property within the properties object in the data source.

    The following example shows an object data source that contains an array called listItemsToShow. Note that the array of items is within the properties object.

     {
   "imageListData": {
     "type": "object",
     "objectId": "imageListDataId",
     "properties": {
       "listItemsToShow": [
         {
           "primaryText": "First list item",
           "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/md_gruyere.png"
         },
         {
           "primaryText": "Second list item",
           "imageSource": "https://d2o906d8ln7ui1.cloudfront.net/images/md_gorgonzola.png"
         }
       ]
     }
   }
 }

  3. Configure the ssmlToSpeech or textToSpeech transformer with the following settings:

    • inputPath – The array of items to speak. The transformer expects the path you provide to be within the properties object, so you don't need to include properties in the path. When the items in your array are objects, specify the specific field within the object that contains the text or SSML.
    • outputName – Set to the string "speech". The AlexaImageList template includes "speech" when handling the list of items, so you must use this exact string.
    • transformer – Either ssmlToSpeech or textToSpeech, depending on the format of the items in the array

    The following example configures the textToSpeech transformer to process the primaryText field for each item in the listItemsToShow array.

     {
   "transformers": [
     {
       "inputPath": "listItemsToShow[*].primaryText",
       "outputName": "speech",
       "transformer": "textToSpeech"
     }
   ]
 }

Bind the speechItems property to the list of items to speak

In your APL document, use a data-binding expression to bind the speechItems property of AlexaImageList to your list of items to speak.

Continuing the previous example, the expression is ${imageListData.properties.listItemsToShow}. This example uses the same primaryText both for display and for speech.

{
  "type": "AlexaImageList",
  "listItems": "${imageListData.properties.listItemsToShow}",
  "speechItems": "${imageListData.properties.listItemsToShow}"
}

Run the SpeakList command for the list

Run the SpeakList command when you want Alexa to read the items provided in speechItems. For example, you might run the command from the onMount handler to read the items after the device displays the document.

  1. Assign the listId parameter on AlexaImageList to an ID unique to your document. You must provide this ID to run SpeakList.

     {
   "type": "AlexaImageList",
   "listId": "myImageListWithItemsToSpeak",
   "listItems": "${imageListData.properties.listItemsToShow}",
   "speechItems": "${imageListData.properties.listItemsToShow}"
 }

  2. Set the componentId property for the SpeakList command to the ID you provided for listId.

    The following example invokes the command in the onMount handler. Alexa speaks the items after the device displays the document.

     {
   "onMount": [
     {
       "type": "SpeakList",
       "delay": 5000,
       "componentId": "myImageListWithItemsToSpeak",
       "start": 0,
       "count": "${imageListData.properties.listItemsToShow.length}",
       "minimumDwellTime": 1000,
       "align": "center"
     }
   ]
 }

The following examples show the complete document and data source. After the device displays the document, Alexa reads the primary text for each of the six items in the list. The SpeakList command includes the five second delay to allow Alexa to speak the normal speech output for the skill response before reading the list items.

AlexaImageList and dynamicIndexList data sources

The AlexaImageList template uses a Sequence. This means you can use a dynamicIndexList data source. With a dynamicIndexList data source, you can do the following:

  • Display large lists progressively as the user scrolls through the content (lazy loading).
  • Update the items the data source after it is already displayed, so you can change the values on the screen without sending an entirely new document.

To use a dynamicIndexList data source with AlexaImageList

  1. Follow the dynamicIndexList structure shown in dynamicIndexList data source. Don't include any other properties not defined in this structure.
  2. Put your list item objects in the items array in the data source.
  3. Bind the data source to the listItems property of AlexaImageList. This binding is equivalent to binding the data source to the data property of a Sequence in a custom layout.

The following examples show a document with an AlexaImageList that uses a dynamicIndexList data source.

For details about defining a dynamicIndexList data source, see dynamicIndexList data source.

For details about the directives and requests you use to manage the data source, see Alexa.Presentation.APL Interface Reference.

AlexaImageList example

In this example, selecting a list item sends your skill a UserEvent with "ListItemSelected" and the number of the list item.

A simple AlexaImageList
A simple AlexaImageList