Question

我想每10分钟保存一次我的位置，
我有代码从gps中获取位置然后我想每隔10分钟将我的位置保存在数据库中这是我的代码：

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    LocationManager locationManager;
    String context = Context.LOCATION_SERVICE;
    locationManager = (LocationManager)getSystemService(context);

    Criteria criteria = new Criteria();
    criteria.setAccuracy(Criteria.ACCURACY_FINE);
    criteria.setAltitudeRequired(false);
    criteria.setBearingRequired(false);
    criteria.setCostAllowed(true);
    criteria.setPowerRequirement(Criteria.POWER_LOW);
    String provider = locationManager.getBestProvider(criteria, true);

    updateWithNewLocation(null);

    locationManager.requestLocationUpdates(provider, (10*60*1000), 10,
                                           locationListener);
}
private final LocationListener locationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
      updateWithNewLocation(location);
    }

    public void onProviderDisabled(String provider){
      updateWithNewLocation(null);
    }

    public void onProviderEnabled(String provider){ }
    public void onStatusChanged(String provider, int status, 
                                Bundle extras){ }
  };
  public void updateWithNewLocation(Location location) {


        if (location != null) {
            Dbhelper helper = new Dbhelper(this);
            final SQLiteDatabase db = helper.getWritableDatabase();
            long time = System.currentTimeMillis();
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");
            final String curTime = df.format(time);
            final double lat = location.getLatitude();
            final double lng = location.getLongitude();
            final double alt = location.getAltitude();
            System.out.println(lat);
            System.out.println(lng);
            System.out.println(alt);
            /*db.execSQL("INSERT INTO location (longitude,latitude,altitude,tgl_buat) VALUES " +
            "('"+lng+"','"+lat+"','"+alt+"','"+curTime+"')");
            db.close();*/
            Timer timer = new Timer();
            timer.schedule(new TimerTask(){
                @Override
                public void run(){
                    db.execSQL("INSERT INTO location (longitude,latitude,altitude,tgl_buat) VALUES " +
                            "('"+lng+"','"+lat+"','"+alt+"','"+curTime+"')");
                    db.close();
                }
            }, 10*60*1000, 10*60*1000);

          } 
       }

但是每10分钟没有保存我怎么能解决这个问题？谢谢：）

Answer 1

您可以在将来某个时候使用处理程序进行更新：

http://developer.android.com/reference/android/os/Handler.html

http://www.vogella.com/articles/AndroidPerformance/article.html#concurrency_handler

Answer 2

您的位置确实不会保存在数据库中，因为每次更新您的位置时（通过onLocationChanged(Location location)），您都会创建一个新的计时器实例。

您应该做的是在timer方法中进行OnCreate()初始化。然后声明这些变量

double lat = location.getLatitude();
double lng = location.getLongitude();
double alt = location.getAltitude();

作为全局，并使用onLocationChanged(Location location)方法更新它们。这样，只要计时器调用数据库中的持久性，lat, lng, alt值就会可用，并根据您的最新位置进行更新。

更新：

在这里，我修复了你的代码。你能试试吗？

//decalred as global variables
String curTime;
double lat;
double lng;
double alt;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    LocationManager locationManager;
    String context = Context.LOCATION_SERVICE;
    locationManager = (LocationManager)getSystemService(context);

    Criteria criteria = new Criteria();
    criteria.setAccuracy(Criteria.ACCURACY_FINE);
    criteria.setAltitudeRequired(false);
    criteria.setBearingRequired(false);
    criteria.setCostAllowed(true);
    criteria.setPowerRequirement(Criteria.POWER_LOW);
    String provider = locationManager.getBestProvider(criteria, true);

        //Initialize timer
        Timer timer = new Timer();
            timer.schedule(new TimerTask(){
                @Override
                public void run(){
                    db.execSQL("INSERT INTO location (longitude,latitude,altitude,tgl_buat) VALUES " +
                            "('"+lng+"','"+lat+"','"+alt+"','"+curTime+"')");
                    db.close();
                }
            }, 10*60*1000, 10*60*1000);


    updateWithNewLocation(null);

    locationManager.requestLocationUpdates(provider, (10*60*1000), 10,
                                           locationListener);
}
private final LocationListener locationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
      updateWithNewLocation(location);
    }

    public void onProviderDisabled(String provider){
      updateWithNewLocation(null);
    }

    public void onProviderEnabled(String provider){ }
    public void onStatusChanged(String provider, int status, 
                                Bundle extras){ }
  };
  public void updateWithNewLocation(Location location) {


        if (location != null) {
            Dbhelper helper = new Dbhelper(this);
            final SQLiteDatabase db = helper.getWritableDatabase();
            long time = System.currentTimeMillis();
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd kk:mm:ss");
            curTime = df.format(time);
            lat = location.getLatitude();
            lng = location.getLongitude();
            alt = location.getAltitude();
            System.out.println(lat);
            System.out.println(lng);
            System.out.println(alt);

        } 

      }

设置计时器在10分钟内做一些事情

2 个答案: