我对此进行了大量研究，但仍未找到任何解决方案，因此请仔细阅读并提供帮助，基本上就像当我们通过拖动标记在地图上选择一个位置时，我不希望地图刷新并重置值，并且重新渲染发生后，图钉又回到中心，
“ shouldcomponentupdate”中有什么解决方案吗？这不允许您重新渲染整个内容，但是当我将标记从一个位置移动到另一个位置时，通过不断更新在输入字段中检索到的值（例如address，lat和long），就可以了！
而且我还应该在shouldcomponentupdate方法中尝试其他操作，例如将其返回为false，但是在那边地图没有重新渲染，我可以将销钉从我停下来的地方拖出来，我可以在下面的控制台中看到更新的位置，但是这些位置的值未显示在提供的输入字段中！
用简单的话来说，只要我将大头针拖放到位置上，就必须连续检索位置值，而大头针不会回到地图中心，这样我就可以从我的位置继续检索位置将标记图钉留在地图上。
请帮帮我！！我从网上获取了这段代码，我想实现这些更改
import React, { Component } from 'react';
import { withGoogleMap, GoogleMap, withScriptjs, InfoWindow, Marker } from "react-google-maps";
import Geocode from "react-geocode";
import Autocomplete from 'react-google-autocomplete';
Geocode.setApiKey( "AIzaSyDGe5vjL8wBmilLzoJ0jNIwe9SAuH2xS_0" );
Geocode.enableDebug();
class Map extends Component{
constructor( props ){
super( props );
this.state = {
address: '',
city: '',
area: '',
state: '',
mapPosition: {
lat: this.props.center.lat,
lng: this.props.center.lng
},
markerPosition: {
lat: this.props.center.lat,
lng: this.props.center.lng
}
}
}
/**
* Get the current address from the default map position and set those values in the state
*/
componentDidMount() {
Geocode.fromLatLng( this.state.mapPosition.lat , this.state.mapPosition.lng ).then(
response => {
const address = response.results[0].formatted_address,
addressArray = response.results[0].address_components,
city = this.getCity( addressArray ),
area = this.getArea( addressArray ),
state = this.getState( addressArray );
console.log( 'city', city, area, state );
this.setState( {
address: ( address ) ? address : '',
area: ( area ) ? area : '',
city: ( city ) ? city : '',
state: ( state ) ? state : '',
} )
},
error => {
console.error( error );
}
);
};
/**
* Component should only update ( meaning re-render ), when the user selects the address, or drags the pin
*
* @param nextProps
* @param nextState
* @return {boolean}
*/
shouldComponentUpdate( nextProps, nextState ){
if (
this.state.markerPosition.lat !== this.props.center.lat ||
this.state.address !== nextState.address ||
this.state.city !== nextState.city ||
this.state.area !== nextState.area ||
this.state.state !== nextState.state
) {
return true
} else if ( this.props.center.lat === nextProps.center.lat ){
return false
}
}
/**
* Get the city and set the city input value to the one selected
*
* @param addressArray
* @return {string}
*/
getCity = ( addressArray ) => {
let city = '';
for( let i = 0; i < addressArray.length; i++ ) {
if ( addressArray[ i ].types[0] && 'administrative_area_level_2' === addressArray[ i ].types[0] ) {
city = addressArray[ i ].long_name;
return city;
}
}
};
/**
* Get the area and set the area input value to the one selected
*
* @param addressArray
* @return {string}
*/
getArea = ( addressArray ) => {
let area = '';
for( let i = 0; i < addressArray.length; i++ ) {
if ( addressArray[ i ].types[0] ) {
for ( let j = 0; j < addressArray[ i ].types.length; j++ ) {
if ( 'sublocality_level_1' === addressArray[ i ].types[j] || 'locality' === addressArray[ i ].types[j] ) {
area = addressArray[ i ].long_name;
return area;
}
}
}
}``
};
/**
* Get the address and set the address input value to the one selected
*
* @param addressArray
* @return {string}
*/
getState = ( addressArray ) => {
let state = '';
for( let i = 0; i < addressArray.length; i++ ) {
for( let i = 0; i < addressArray.length; i++ ) {
if ( addressArray[ i ].types[0] && 'administrative_area_level_1' === addressArray[ i ].types[0] ) {
state = addressArray[ i ].long_name;
return state;
}
}
}
};
/**
* And function for city,state and address input
* @param event
*/
onChange = ( event ) => {
this.setState({ [event.target.name]: event.target.value });
};
/**
* This Event triggers when the marker window is closed
*
* @param event
*/
onInfoWindowClose = ( event ) => {
};
/**
* When the marker is dragged you get the lat and long using the functions available from event object.
* Use geocode to get the address, city, area and state from the lat and lng positions.
* And then set those values in the state.
*
* @param event
*/
onMarkerDragEnd = ( event ) => {
let newLat = event.latLng.lat(),
newLng = event.latLng.lng();
Geocode.fromLatLng( newLat , newLng ).then(
response => {
const address = response.results[0].formatted_address,
addressArray = response.results[0].address_components,
city = this.getCity( addressArray ),
area = this.getArea( addressArray ),
state = this.getState( addressArray );
this.setState( {
address: ( address ) ? address : '',
area: ( area ) ? area : '',
city: ( city ) ? city : '',
state: ( state ) ? state : ''
} )
},
error => {
console.error(error);
}
);
};
/**
* When the user types an address in the search box
* @param place
*/
onPlaceSelected = ( place ) => {
console.log( 'plc', place );
const address = place.formatted_address,
addressArray = place.address_components,
city = this.getCity( addressArray ),
area = this.getArea( addressArray ),
state = this.getState( addressArray ),
latValue = place.geometry.location.lat(),
lngValue = place.geometry.location.lng();
// Set these values in the state.
this.setState({
address: ( address ) ? address : '',
area: ( area ) ? area : '',
city: ( city ) ? city : '',
state: ( state ) ? state : '',
markerPosition: {
lat: latValue,
lng: lngValue
},
mapPosition: {
lat: latValue,
lng: lngValue
},
})
};
render(){
const AsyncMap = withScriptjs(
withGoogleMap(
props => (
<GoogleMap google={ this.props.google }
defaultZoom={ this.props.zoom }
defaultCenter={{ lat: this.state.mapPosition.lat, lng: this.state.mapPosition.lng }}
>
{/* InfoWindow on top of marker */}
<InfoWindow
onClose={this.onInfoWindowClose}
position={{ lat: ( this.state.markerPosition.lat + 0.0018 ), lng: this.state.markerPosition.lng }}
>
<div>
<span style={{ padding: 0, margin: 0 }}>{ this.state.address }</span>
</div>
</InfoWindow>
{/*Marker*/}
<Marker google={this.props.google}
name={'Dolores park'}
draggable={true}
onDragEnd={ this.onMarkerDragEnd }
position={{ lat: this.state.markerPosition.lat, lng: this.state.markerPosition.lng }}
/>
<Marker />
{/* For Auto complete Search Box */}
<Autocomplete
style={{
width: '100%',
height: '40px',
paddingLeft: '16px',
marginTop: '2px',
marginBottom: '100px'
}}
onPlaceSelected={ this.onPlaceSelected }
types={['(regions)']}
/>
</GoogleMap>
)
)
);
let map;
if( this.props.center.lat !== undefined ) {
map = <div>
<div>
<div className="form-group">
<label htmlFor="">City</label>
<input type="text" name="city" className="form-control" onChange={ this.onChange } readOnly="readOnly" value={ this.state.city }/>
</div>
<div className="form-group">
<label htmlFor="">Area</label>
<input type="text" name="area" className="form-control" onChange={ this.onChange } readOnly="readOnly" value={ this.state.area }/>
</div>
<div className="form-group">
<label htmlFor="">State</label>
<input type="text" name="state" className="form-control" onChange={ this.onChange } readOnly="readOnly" value={ this.state.state }/>
</div>
<div className="form-group">
<label htmlFor="">Address</label>
<input type="text" name="address" className="form-control" onChange={ this.onChange } readOnly="readOnly" value={ this.state.address }/>
</div>
</div>
<AsyncMap
googleMapURL="https://maps.googleapis.com/maps/api/js?key=AIzaSyDGe5vjL8wBmilLzoJ0jNIwe9SAuH2xS_0&libraries=places"
loadingElement={
<div style={{ height: `100%` }} />
}
containerElement={
<div style={{ height: this.props.height }} />
}
mapElement={
<div style={{ height: `100%` }} />
}
/>
</div>
} else {
map = <div style={{height: this.props.height}} />
}
return( map )
}
}
export default Map
当我发现您的问题时，我正在寻找相同问题的解决方案。我知道它的帖子很晚，但是我的回答将对那些来这里的人有所帮助。shouldComponentUpdate（）方法用于避免不必要的组件渲染。因此，我们必须在此方法中放置条件，以便基于该条件返回true或false。在您的代码中，按如下所示替换shouldcomponentupdate方法：
shouldComponentUpdate( nextProps, nextState ){
if (
this.state.markerPosition.lat !== this.props.center.lat ||
this.state.address !== nextState.address
) {
return false
} else if ( this.props.center.lat === nextProps.center.lat ){
return true
}
}
对我有用。希望能有所帮助。谢谢！