秋·風

如果用xe6自帶的LocationSensor控件，默認優先使用網絡位置，網絡位置定位精度不準確，不能滿足高精度定位的要求。但xe6自帶的LocationSensor控件不能指定網絡定位優先還是GPS定位優先，如果調用java API是可以指定優先使用GPS定位，以下代碼經實測證實是可以直接指定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);//位置發生變化時，顯示經、緯度

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);

      // 監聽狀態
      // 綁定監聽，有4個參數
      // 參數1，設備：有GPS_PROVIDER和NETWORK_PROVIDER兩種
      // 參數2，位置信息更新周期，單位毫秒
      // 參數3，位置變化最小距離：當位置距離變化超過此值時，將更新位置信息
      // 參數4，監聽
      // 備注：參數2和3，如果參數3不為0，則以參數3為準；參數3為0，則通過時間來定時更新；兩者為0，則隨時刷新
      // 1秒更新一次，或最小位移變化超過1米更新一次；
      // 注意：此處更新準確度非常低，推薦在service里面啟動一個Thread，在run中sleep(10000);然后執行handler.sendMessage(),更新位置

  end;

 FLocationManager.isProviderEnabled(TJLocationManager.JavaClass.GPS_PROVIDER);

  FLocationManager.isProviderEnabled(TJLocationManager.JavaClass.NETWORK_PROVIDER);

  onLocationChanged(location);

end