API v8.5 Changes
NOTE: These are the changes in Developer API v8.5. It is supported in Layar client and LayarSDK v8.5 (and above) on both Android and iPhone.
In Layar API v8.5 we added the following features:
GetPOIs response change
Event Handlers
Layar 8.5 introduces the concept of event handlers to the Layar API, which allows actions or POI updates to be triggered after certain events. This enables developers to add more complex functionality to their experiences, e.g. sequencing of videos, but also dynamic content without server interaction.
Event Types
The following event types are defined on the hotspots 'object' element:
- onLoad Triggered when the object has been loaded successfully (Similar as onCreate)
- onClick Triggered when the object has been clicked (similar behaviour as the POI action)
- onPlaybackStart Triggered when the video or audio object playback started
- onPlaybackFinish Triggered when the video or audio object playback finished
"object:" {"url": "...","contentType": "image/png","size": 1.0,"onClick": {"action": {"contentType": "application/vnd.layar.internal","uri": "layar://[layername]/?parameters"}}}
Event Handler object
The event handler object tied to an event is a simple JSON dictionary with 3 optional attributes.
| Attribute name | Attribute name |
|---|---|
| action | Action to be executed the moment the event is triggered. Follow the same syntax as the hotspots 'actions' attribute. |
| update | The update attribute can be used to perform a POI update without requiring a server call. |
| handler | String value referring to another event handler registered in the global event handler registry. |
An event handler should have at minimum one of these attributes, but can have more. If it defines more, all actions are triggered. This allows us to update POIs, but still do an async server call to notify the backend of the event.
| Attribute name | Attribute name |
|---|---|
| hotspots | Array of hotspots that need to be added/updated |
| deleted_hotspots | Array of hotspot ids that need to be deleted |
The update object allows us to add/update hotspots dynamically as a result of a triggered event without having to rely on server calls. The app handles this as if we would have received a getPOIrequest response with fullRefresh="false".
"object": {
"url": "...",
"contentType": "image/jpeg",
"size": 1.0,
"onClick": {
"update": {
"hotspots": [
{
"id": "poiToUpdate",
...
}
],
"deletedHotspots": ["poiId1ToDelete", "poiId2ToDelete"]
}
}
}
Global Event Handler Registry
At the root level of a getPOIs response a new attribute named 'handlers' is added. The value of this attribute is a JSON dict. This allows the developer to specify event handlers at a global level so they can be reused by different POI objects. This also allows us to have more advanced functionality like toggles.
"hotspots": [{
"id": "door",
"object:" {
...
"onClick": {
"handler": "open_door"
}
... }}],
"handlers": {
"open_door": {
"update": {
"hotspots": [{
"id": "door",
"object": {
...
"onClick": {
"handler": "close_door"
}
...
}
}]
}
},
"close_door": {
"update": {
"hotspots": [{
"id": "door",
"object": {
...
"onClick": {
"handler": "open_door"
}
...
}
}]
}
}
}