[英]How can I render markers on a map in React using a for loop?
我正在嘗試使用React,我想在地圖上渲染一些標記(我正在使用Google Maps API)。 現在,如果我對標記進行硬編碼(在示例中,5個標記,每個標記具有不同的坐標,名稱和描述,如下面的位置數組),一切都很好。 但是,如果我想循環遍歷數組並在沒有硬編碼的情況下渲染它們呢? 我在render()之前定義了renderMarkers函數。 任何幫助,將不勝感激。 謝謝!
/* Main component state */
state = {
showingInfoWindow: false,
activeMarker: {},
selectedPlace: {},
mapReady: true,
desc: '',
animation: null,
locations:
[
{
"locationName": "name1",
"position": '{"lat": "lat1", "lng": "lng1"}',
"desc": "desc1"
},
{
"locationName": "name2",
"position": '{"lat": "lat2", "lng": "lng2"}',
"desc": "desc2"
},
{
"locationName": "name3",
"position": '{"lat": "lat3", "lng": "lng3"}',
"desc": "desc3"
},
{
"locationName": "name4",
"position": '{"lat": "lat4", "lng": "lng4"}',
"desc": "desc4."
},
{
"locationName": "name5",
"position": '{"lat": "lat5, "lng": "lng5"}',
"desc": "desc5."
}
]
};
/* Function to render the markers, each with their relevant info taken from the state.locations array, on the map */
renderMarkers = () => {
for (let i = 0; i < this.state.locations.length; i++) {
return <Marker
onClick = { this.onMarkerClick }
title = { this.state.locations[i].locName }
position = { JSON.parse(this.state.locations[i].position) }
desc = { this.state.locations[i].desc }
animation = { this.state.animation[i] }
name = { this.state.locations[i].locName } />
}
}
map
函數創建標記數組。 renderMarkers
函數應該放在render
函數之外。 否則,每次更改組件的狀態時都會重新創建renderMarkers
,因為在每次狀態更改(性能命中)時都會調用render
。 renderMarkers() {
return this.state.locations.map((location, i) => {
return <Marker
key={ i }
onClick = { this.onMarkerClick }
title = { location.locName }
position = { JSON.parse(location.position) }
desc = { location.desc }
animation = { this.state.animation[i] }
name = { location.locName } />
})
}
render() {
return <div>{ this.renderMarkers() }</div>
}
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