react-native-webview-leaflet
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A React Native component that uses a React Native WebView to provide a Leaflet map.
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Markdown
# React Native Webview Leaflet
## A Leaflet map component with no native code for React Native applications
### ⚠️ This is version 4 of this library. It includes breaking changes from previous versions.
#### Difference Between Versions
Like version 2, version 3 builds on [react-leaflet](https://github.com/PaulLeCam/react-leaflet). The primary new feature is the ability to specify map tiles. See below for more details.
### Why Use This Library
This component is useful if you want to display HTML elements on an interactive map. Since the elements are just HTML items, you can use SVG's, emojis, text, images, etc., and they can even be animated, updated, and changed as required.
### Why Not Use This Library
You may not want to use this library if you'd rather use Google map tiles and data vice the tiles and map data from Open Street Maps.
[](https://www.npmjs.com/package/react-native-webview-leaflet)
[](https://www.npmjs.com/package/react-native-webview-leaflet)
[](https://www.npmjs.com/package/react-native-webview-leaflet)
[](https://github.com/react-native-component/react-native-webview-leaflet/blob/master/LICENSE)
## Installation
Install using npm or yarn like this:
```javascript
npm install --save react-native-webview-leaflet
```
or
```javascript
yarn add react-native-webview-leaflet
```
## Usage
and import like so
```javascript
import WebViewLeaflet from "react-native-webview-leaflet";
```
A typical example is shown below:
```javascript
<WebViewLeaflet
ref={component => (this.webViewLeaflet = component)}
// Optional: a callback that will be called when the map is loaded
onLoad={this.onLoad}
// Optional: the component that will receive map events}
eventReceiver={this}
// Optional: the center of the displayed map
centerPosition={this.state.mapCenterPosition}
// Optional: a list of markers that will be displayed on the map
markers={this.state.markers}
// Required: the map layers that will be displayed on the map. See below for a description of the map layers object
mapLayers={mapLayers}
// Optional: display a marker to be at a given location
ownPositionMarker={{
coords: this.state.currentLocation,
icon: "❤️",
size: [24, 24],
animation: {
name: "pulse",
duration: ".5",
delay: 0,
interationCount: "infinite"
}
}}
// Optional (defaults to false): display a button that centers the map on the coordinates of ownPostionMarker. Requires that "ownPositionMarker" prop be set
centerButton={true}
// Optional (defaults to false): cluster icons that are in the same area
useMarkerClustering={true}
/>
```
After loading, the map expects to receive an array of map layer information objects. A sample object showing a [MapBox](https://www.mapbox.com/) tile layer is shown below.
```javascript
{
name: 'streets', // the name of the layer, this will be seen in the layer selection control
checked: 'true', // if the layer is selected in the layer selection control
type: 'TileLayer', // the type of layer as shown at https://react-leaflet.js.org/docs/en/components.html#raster-layers
baseLayer: true,
// url of tiles
url: `https://api.tiles.mapbox.com/v4/mapbox.streets/{z}/{x}/{y}.png?access_token=${mapboxToken}`,
// attribution string to be shown for this layer
attribution:
'&copy <a href="http://osm.org/copyright">OpenStreetMap</a> contributors'
}
```
The format of the object depends on the type of layer to be displayed, and corresponds to the Raster Layers in react-leaflet
https://react-leaflet.js.org/docs/en/components.html#raster-layers
**NOTE: Image and VideoOverlay layers do not currently work.**
Example objects are shown in the mockMapLayers.js file in this repository.
### Communicating with the map
#### Listening for Events
This library supports map clicked, map marker clicked, and the map events that are exposed by Leaflet.
##### Map Clicked and Map Marker Clicked Events
To receive map clicked and on map marker clicked events, add the following functions to the component identified by the eventReceiver prop.
```javascript
onMapClicked = ({ payload }) => {
console.log(`Map Clicked: app received: ${payload.coords}`);
this.showAlert("Map Clicked", `Coordinates = ${payload.coords}`);
};
onMapMarkerClicked = ({ payload }) => {
console.log(`Marker Clicked: ${payload.id}`);
this.showAlert("Marker Clicked", `Marker ID = ${payload.id}`);
};
```
##### Leaflet Map Events
To react to leaflet map events, you need to create functions in your component to handle them. These functions' names must be camelCased and prefixed by 'on'.
For example, to listen for Leaflet's `zoomlevelschange` event, you will need to create a function
called `onZoomLevelsChange`. These functions will receive the following object
```javascript
{
center, // center of the map
bounds, // the bounds of the map
zoom; // the zoom level of the map
}
```
### Sending Events to the Map
The map can be be updated by sending messages from your component to the WebViewLeaflet component via its reference like so:
```javascript
this.webViewLeaflet.sendMessage({
zoom: 6,
locations: this.state.locations, // an array of locations
showAttributionControl: this.state.mapState.showAttributionControl, // a boolean controlling whether the map displays its attribution control
showZoomControl: this.state.mapState.showZoomControl // a boolean controlling whether the map displays its zoom control
});
```
A [react-leaflet](https://react-leaflet.js.org/en/) component makes up the map that is rendered by `WebViewLeaflet`. This allows messages like the one above to be used to directly set values in the map's state.
### Creating Map Markers
The map builds and displays its markers based on the value of the `locations` key in its own state. You can update the value of it's `locations` by sending a message containing an object that contains a key of `locations` and a value that is an array of location objects like the one shown below. An example of such a call and a location object is show below.
```javascript
// sending locations to the map
this.webViewLeaflet.sendMessage({
locations: [...this.state.locations]
});
```
```javascript
// a location object
{
id: uuidV1(), // The ID attached to the marker. It will be returned when onMarkerClicked is called
coords: [LATITUDE, LONGITUDE], // Latitude and Longitude of the marker
icon: '🍇', // HTML element that will be displayed as the marker. It can also be text or an SVG string.
// The child object, "animation", controls the optional animation that will be attached to the marker.
// See below for a list of available animations
animation: {
name: animations[Math.floor(Math.random() * animations.length)],
duration: Math.floor(Math.random() _ 3) + 1,
delay: Math.floor(Math.random()) _ 0.5,
interationCount
}
// optional size for this individual icon
// will default to the WebViewLeaflet `defaultIconSize` property if not provided
size: [64, 64],
}
```
### Available Animations
Animations for "bounce", "fade", "pulse", "jump", "waggle", "spin", and "beat" can be specified in the animation.name property of an individual location.
### Animation Information
Animations are kept in the file [markers.css](https://github.com/reggie3/react-native-webview-leaflet/blob/master/web/markers.css) They are just keyframe animations like this:
```javascript
@keyframes spin {
50% {
transform: rotateZ(-20deg);
animation-timing-function: ease;
}
100% {
transform: rotateZ(360deg);
}
}
```
```
## Changelog
### 4.2.0
* Replace Expo dependency with expo-asset-utils
* Fixed bug that caused map to not display when no ownPositionMarker was provided
### 4.1.15
* Keep own position marker from being clustered
### 4.1.0
* Added optional marker clustering using react-leaflet-markercluster
* Update preview video in readme
### 4.0.0
* Fixed map centering, and map centering button (see issue #36(https://github.com/reggie3/react-native-webview-leaflet/issues/36) )
#### BREAKING CHANGES:
* Center map on own current location button defaults to not being shown
* Center map on own current location button requires that a "ownPositionMarker" object be passed to the WebViewLeaflet component
* WebViewLeaflet component requires a "centerPosition" prop for initial centering
* Map tile Layers are now passed as props to the WebViewLeaflet component
### 3.1.45
* Works in production APK files.
* Renders http images as map icons.
### 3.0.0
* Introduced user specified tile layers.
### 2.0.0
* Initial release of version 2 built on React-Leaflet
## LICENSE
MIT
```