delphi xe6 调用java GPS的方法

如果用xe6自带的LocationSensor控件，默认优先使用网络位置，网络位置定位精度不准确，不能满足高精度定位的要求。但xe6自带的LocationSensor控件不能指定网络定位优先还是GPS定位优先，如果调用java API是可以指定优先使用GPS定位，以下代码经实测证实是可以直接指定GPS定位的。

uses Androidapi.JNI.Location, Androidapi.JNIBridge, Androidapi.JNI.JavaTypes,
Androidapi.JNI.Os,FMX.Helpers.Android,Androidapi.JNI.GraphicsContentViewText;

type
TLocationListener = class;
TForm1 = class(TForm)

. . . . . .

private
{ Private declarations }
FLocationManager : JLocationManager;
locationListener : TLocationListener;
public
destructor Destroy; override;
{ Public declarations }
procedure onLocationChanged(location: JLocation);
end;
//Sensore GPS
TLocationListener = class(TJavaLocal, JLocationListener)
private
[weak]
FParent : TForm1;
public
constructor Create(AParent : TForm1);
procedure onLocationChanged(location: JLocation); cdecl;
procedure onProviderDisabled(provider: JString); cdecl;
procedure onProviderEnabled(provider: JString); cdecl;
procedure onStatusChanged(provider: JString; status: Integer; extras: JBundle); cdecl;
end;

. . . . .

constructor TLocationListener.Create(AParent: TForm1);
begin
inherited Create;
FParent := AParent;
end;

procedure TLocationListener.onLocationChanged(location: JLocation);
begin
FParent.onLocationChanged(location);
end;

procedure TLocationListener.onProviderDisabled(provider: JString);
begin
end;

procedure TLocationListener.onProviderEnabled(provider: JString);
begin
end;

procedure TLocationListener.onStatusChanged(provider: JString; status: Integer; extras: JBundle);
begin
end;

destructor TForm1.Destroy;
begin
if Assigned(locationListener) then
FLocationManager.removeUpdates(locationListener);
inherited;
end;

procedure TForm1.onLocationChanged(location: JLocation);//位置发生变化时，显示经、纬度
begin
if Assigned(location) then
begin
//variabili da recuperare dal sensore
Label4.Text := location.getLatitude.ToString;
Label5.Text := location.getLongitude.ToString;
Label6.Text := location.getAltitude.ToString;
Label8.Text := location.getSpeed.ToString;
Label10.Text := location.getTime.ToString;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
var LocationManagerService: JObject;
location : JLocation;
begin
if not Assigned(FLocationManager) then
begin
LocationManagerService := SharedActivityContext.getSystemService(TJContext.JavaClass.LOCATION_SERVICE);
FLocationManager := TJLocationManager.Wrap((LocationManagerService as ILocalObject).GetObjectID);
if not Assigned(locationListener) then locationListener := TLocationListener.Create(self);
FLocationManager.requestLocationUpdates(TJLocationManager.JavaClass.GPS_PROVIDER, 1000, 0, locationListener, TJLooper.JavaClass.getMainLooper);
// 监听状态
// 绑定监听，有4个参数
// 参数1，设备：有GPS_PROVIDER和NETWORK_PROVIDER两种
// 参数2，位置信息更新周期，单位毫秒
// 参数3，位置变化最小距离：当位置距离变化超过此值时，将更新位置信息
// 参数4，监听
// 备注：参数2和3，如果参数3不为0，则以参数3为准；参数3为0，则通过时间来定时更新；两者为0，则随时刷新
// 1秒更新一次，或最小位移变化超过1米更新一次；
// 注意：此处更新准确度非常低，推荐在service里面启动一个Thread，在run中sleep(10000);然后执行handler.sendMessage(),更新位置
end;
FLocationManager.isProviderEnabled(TJLocationManager.JavaClass.GPS_PROVIDER);
FLocationManager.isProviderEnabled(TJLocationManager.JavaClass.NETWORK_PROVIDER);
onLocationChanged(location);
end