a8f4f70636
See https://github.com/pre-commit/pre-commit-hooks?tab=readme-ov-file#trailing-whitespace
38 lines
1.6 KiB
Markdown
38 lines
1.6 KiB
Markdown
# Add live realtime data
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{{ activity_source_note("RealTimeGeoJsonActivity.kt") }}
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In this example you will learn how to add a live GeoJSON source. We have set up a [lambda function](https://m6rgfvqjp34nnwqcdm4cmmy3cm0dtupu.lambda-url.us-east-1.on.aws/) that returns a new GeoJSON point every time it is called.
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<figure markdown="span">
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<video controls width="250" poster="{{ s3_url("live_realtime_data_thumbnail.jpg") }}" >
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<source src="{{ s3_url("live_realtime_data.mp4") }}" />
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</video>
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</figure>
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First we will create a `GeoJSONSource`.
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```kotlin title="Adding GeoJSON source"
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--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/RealTimeGeoJsonActivity.kt:addSource"
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```
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Next we will create a `SymbolLayer` that uses the source.
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```kotlin title="Adding a SymbolLayer source"
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--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/RealTimeGeoJsonActivity.kt:addLayer"
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```
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We use define a `Runnable` and use `android.os.Handler` with a `android.os.Looper` to update the GeoJSON source every 2 seconds.
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```kotlin title="Defining a Runnable for updating the GeoJSON source"
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--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/RealTimeGeoJsonActivity.kt:Runnable"
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```
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## Bonus: set icon rotation
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You can set the icon rotation of the icon when ever the point is updated based on the last two points.
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```kotlin title="Defining a Runnable for updating the GeoJSON source"
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--8<-- "MapLibreAndroidTestApp/src/main/java/org/maplibre/android/testapp/activity/style/RealTimeGeoJsonActivity.kt:setIconRotation"
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```
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