以下代码
navigator.geolocation.getCurrentPosition(getGeo_Success, getGeo_Fail, {
enableHighAccuracy : true,
maximumAge : Infinity,
timeout : 15000
});
检索当前 GPS 位置 - 但是 - 必须有有效的 GPS 信号(当然,设备的 GPS 功能应该打开)。
如果我们查看其他应用程序(例如 Android 设备上的 map ) - 它知道如何检索最后已知位置 - 即使我没有使用更新地理位置的应用程序打开 map 之前 - 它会在 map 上显示我的位置,即使我在根本没有 GPS 信号的建筑物内。
只是澄清一下:我对应用程序检索到的最后一个地理位置不感兴趣,因为下次我启动它时,该地理位置可能会无关紧要。
问题是:我们如何使用 HTML5/Phonegap 实现这一目标?似乎 navigator.geolocation
只知道检索当前位置,尽管 maximumAge
设置为 Infinity
(这意味着,最后缓存的位置是无关紧要的,所以任何命中都可以(或者,应该是!))
最佳答案
Android 解决方案(iPhone 解决方案如下):
这很整洁:
我使用了 Android 的 native LocationManager
,它提供了 getLastKnownLocation
函数 - 名称说明了一切
这是相关代码
1) 将以下 java 类添加到您的应用程序
package your.package.app.app;
import org.apache.cordova.DroidGap;
import android.content.Context;
import android.location.*;
import android.os.Bundle;
import android.webkit.WebView;
public class GetNativeLocation implements LocationListener {
private WebView mAppView;
private DroidGap mGap;
private Location mostRecentLocation;
public GetNativeLocation(DroidGap gap, WebView view) {
mAppView = view;
mGap = gap;
}
public void onLocationChanged(Location location) {
// TODO Auto-generated method stub
getLocation();
}
public void getLocation() {
LocationManager lm =
(LocationManager)mGap.
getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
String provider = lm.getBestProvider(criteria, true);
lm.requestLocationUpdates(provider, 1000, 500, this);
mostRecentLocation = lm
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
}
public void doInit(){
getLocation();
}
public double getLat(){ return mostRecentLocation.getLatitude();}
public double getLong() { return mostRecentLocation.getLongitude(); }
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
}
2) 确保您的主类如下所示:
public class App extends DroidGap {
// Hold a private member of the class that calls LocationManager
private GetNativeLocation gLocation;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// This line is important, as System Services are not available
// prior to initialization
super.init();
gLocation = new GetNativeLocation(this, appView);
// Add the interface so we can invoke the java functions from our .js
appView.addJavascriptInterface(gLocation, "NativeLocation");
try {
super.loadUrl("file:///android_asset/www/index.html");
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
}
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
}
}
3) 在您的 JS 代码中,只需使用以下方式调用 native java:
window.NativeLocation.doInit();
alert(window.NativeLocation.getLat());
alert(window.NativeLocation.getLong());
这就是大家! :-)
编辑: iPhone解决方案:
我编写了一个小型 Phonegap 插件,它创建了一个自定义类的接口(interface),该类利用 iOS 的 native CLLocationManager
1) Phonegap 插件(JS)
var NativeLocation = {
doInit: function(types, success, fail) {
return Cordova.exec(success, fail, "NativeLocation", "doInit", types);
},
getLongitude: function(types, success, fail){
return Cordova.exec(success, fail, "NativeLocation", "getLongitude", types);
},
getLatitude: function(types, success, fail){
return Cordova.exec(success, fail, "NativeLocation", "getLatitude", types);
}
}
2) Objective-C 类使我们能够调用“CCLocationManager 的函数” *NativeLocation.h*
#import <Foundation/Foundation.h>
#import <Cordova/CDVPlugin.h>
#import <CoreLocation/CoreLocation.h>
@protocol NativeLocationDelegate
@required
- (void)locationUpdate:(CLLocation *)location;
- (void)locationError:(NSError *)error;
@end
@interface NativeLocation : CDVPlugin <CLLocationManagerDelegate> {
id delegate;
NSString* callbackID;
CLLocationManager *lm;
Boolean bEnabled;
double nLat;
double nLon;
}
@property (nonatomic, copy) NSString* callbackID;
@property (nonatomic, retain) CLLocationManager *lm;
@property (nonatomic, readonly) Boolean bEnabled;
@property (nonatomic, assign) id delegate;
- (void) doInit:(NSMutableArray*)arguments
withDict:(NSMutableDictionary*)options;
- (void) getLatitude:(NSMutableArray*)arguments
withDict:(NSMutableDictionary *)options;
- (void) getLongitude:(NSMutableArray*)arguments
withDict:(NSMutableDictionary *)options;
@end
NativeLocation.m
#import "NativeLocation.h"
@implementation NativeLocation
@synthesize callbackID;
@synthesize lm;
@synthesize bEnabled;
@synthesize delegate;
- (void)doInit:(NSMutableArray *)arguments
withDict:(NSMutableDictionary *)options{
if (self != nil){
self.lm = [[[CLLocationManager alloc] init] autorelease];
self.lm.delegate = self;
if (self.lm.locationServicesEnabled == NO)
bEnabled = FALSE;
else bEnabled = TRUE;
}
nLat = 0.0;
nLon = 0.0;
if (bEnabled == TRUE)
[self.lm startUpdatingLocation];
CDVPluginResult* pluginResult = [CDVPluginResult
resultWithStatus:CDVCommandStatus_OK
messageAsString[@"OK"
stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
if (bEnabled == TRUE){
[self writeJavascript: [pluginResult
toSuccessCallbackString:self.callbackID]];
} else {
[self writeJavascript: [pluginResult
toErrorCallbackString:self.callbackID]];
}
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation {
if ([self.delegate conformsToProtocol:@protocol(NativeLocationDelegate)])
[self.delegate locationUpdate:newLocation ];
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
if ([self.delegate conformsToProtocol:@protocol(NativeLocationDelegate)])
[self.delegate locationError:error];
}
- (void)dealloc {
[self.lm release];
[super dealloc];
}
- (void)locationUpdate:(CLLocation *)location {
CLLocationCoordinate2D cCoord = [location coordinate];
nLat = cCoord.latitude;
nLon = cCoord.longitude;
}
- (void)getLatitude:(NSMutableArray *)arguments
withDict:(NSMutableDictionary *)options{
self.callbackID = [arguments pop];
nLat = lm.location.coordinate.latitude;
nLon = lm.location.coordinate.longitude;
CDVPluginResult* pluginResult = [CDVPluginResult
resultWithStatus:CDVCommandStatus_OK
messageAsDouble:nLat];
[self writeJavascript: [pluginResult toSuccessCallbackString:self.callbackID]];
}
- (void)getLongitude:(NSMutableArray *)arguments
withDict:(NSMutableDictionary *)options{
self.callbackID = [arguments pop];
nLat = lm.location.coordinate.latitude;
nLon = lm.location.coordinate.longitude;
CDVPluginResult* pluginResult = [CDVPluginResult
resultWithStatus:CDVCommandStatus_OK messageAsDouble:nLon];
[self writeJavascript: [pluginResult toSuccessCallbackString:self.callbackID]];
}
@end
3) 最后,调用主 .js 中的所有内容
function getLongitudeSuccess(result){
gLongitude = result;
}
function getLatitudeSuccess(result){
gLatitude = result;
}
function runGPSTimer(){
var sTmp = "gps";
theTime = setTimeout('runGPSTimer()', 1000);
NativeLocation.getLongitude(
["getLongitude"],
getLongitudeSuccess,
function(error){ alert("error: " + error); }
);
NativeLocation.getLatitude(
["getLatitude"],
getLatitudeSuccess,
function(error){ alert("error: " + error); }
);
关于jquery - 检索最后已知的地理位置 - Phonegap,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10897081/