Openlayers draw button - button

Question

This example shows a drawing feature upon a button press. It allows you to select different shapes such as points, lines, polygons, etc. I want to incorporate similar functions into my project. But I don't want to select shapes, instead, I want to press the button to turn on the functions of drawing points, lines, polygons, etc.
I assume that button elements should be inserted in the HTML section.
<select id="type">
<option value="Point">Point</option>
<option value="LineString">LineString</option>
<option value="Polygon">Polygon</option>
<option value="Circle">Circle</option>
<option value="None">None</option>
</select>
I tried as below.
</div>
<div id="type">
<button value="Point">button1</button>
<button value="Polygon">button2</button>
<button value="LineString">button3</button>
</div>
It seems to me that something needs to change in the script as well.
var typeSelect = document.getElementById('type');
var draw; // global so we can remove it later
function addInteraction() {
var value = typeSelect.value;
if (value !== 'None') {
draw = new Draw({
source: source,
type: typeSelect.value,
});
map.addInteraction(draw);
}
}
Can somebody please help me?

Answer 1

Change the select to buttons.
<div id="type">
<button id="Point" value="Point">Point</button>
<button id="Polygon" value="Polygon">Polygon</button>
<button id="LineString" value="LineString">LineString</button>
<button id="None" value="None">None</button>
</div>
Add a click listener to each button to set the interaction appropriately
/**
* Handle button clicks.
*/
function handleBtnClick() {
var element=this;
map.removeInteraction(draw);
addInteraction(element);
};
document.getElementById("Point").addEventListener('click', handleBtnClick);
document.getElementById("Polygon").addEventListener('click', handleBtnClick);
document.getElementById("LineString").addEventListener('click', handleBtnClick);
document.getElementById("None").addEventListener('click', handleBtnClick);
working example
code snippet:
var raster = new ol.layer.Tile({ // TileLayer({
source: new ol.source.OSM(),
});
var source = new ol.source.Vector({ // VectorSource({
wrapX: false
});
var vector = new ol.layer.Vector({ // VectorLayer({
source: source,
});
var map = new ol.Map({
layers: [raster, vector],
target: 'map',
view: new ol.View({
center: [-11000000, 4600000],
zoom: 4,
}),
});
var typeSelect = document.getElementById('type');
var draw; // global so we can remove it later
function addInteraction(element) {
var value = element.value;
if (value !== 'None') {
draw = new ol.interaction.Draw({
source: source,
type: value,
});
map.addInteraction(draw);
}
}
/**
* Handle button clicks.
*/
function handleBtnClick() {
var element = this;
map.removeInteraction(draw);
addInteraction(element);
// return false;
};
document.getElementById("Point").addEventListener('click', handleBtnClick);
document.getElementById("Polygon").addEventListener('click', handleBtnClick);
document.getElementById("LineString").addEventListener('click', handleBtnClick);
document.getElementById("None").addEventListener('click', handleBtnClick);
addInteraction(document.getElementById('None'));
html,
body {
height: 100%;
width: 100%;
padding: 0px;
margin: 0px;
}
.map {
height: 90%;
width: 100%;
}
<title>Draw Features</title>
<link rel="stylesheet" href="https://openlayers.org/en/v6.4.3/css/ol.css" type="text/css">
<!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
<script src="https://unpkg.com/elm-pep"></script>
<script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io#master/en/v6.4.3/build/ol.js"></script>
<div id="map" class="map"></div>
<label>Geometry type </label>
<div id="type">
<button id="Point" value="Point">Point</button>
<button id="Polygon" value="Polygon">Polygon</button>
<button id="LineString" value="LineString">LineString</button>
<button id="None" value="None">None</button>
</div>