Question

对于速度测量应用程序，我需要在每四秒后获得经度和经度更新。我在两次调用getLatitude和getLongitude函数之间使用了sleep函数。但是在屏幕上打印显示值保持不变，即lon1和lon2，因为双精度数（十进制后的14位）具有完全相同的值，因此速度也显示为0。

如何在固定的时间间隔（此处为4秒）后获得纬度和经度？非常感谢提前。

   locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        locationListener = new LocationListener()
        {
            @Override
            public void onLocationChanged(Location location) {
                double r = 6371;
                double lat1 = location.getLatitude();
                double lon1 = location.getLongitude(); // To get initial longitude
                SystemClock.sleep(4000);              /////This seems ineffective.
                double lat2 = location.getLatitude();
                double lon2 = location.getLongitude(); // and here
                double dlat = (lat2-lat1)*22/7/180;
                double dlon = (lon2-lon1)*22/7/180;
             
                textView.append("lon1:"+lon1+" lon2:"+lon2+" Kmph\n");
                lat1 = lat1*22/7/180;
                lat2 = lat2*22/7/180;
                double h = ((1-Math.cos(dlat))/2) + Math.cos(lat1)*Math.cos(lat2)*(1-Math.cos(dlon))/2;
                double d = 2**Math.asin(Math.sqrt(h));
                double sp = d/3;
                textView.append(" "+ sp + " Kmph\n");
            }

            

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {

            }

            @Override
            public void onProviderEnabled(String s) {

            }

            @Override
            public void onProviderDisabled(String s) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                startActivity(intent);
            }
        };
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[]{
                        Manifest.permission.ACCESS_FINE_LOCATION,Manifest.permission.ACCESS_COARSE_LOCATION,
                        Manifest.permission.INTERNET
                },10);
                return;
            }
        }else {
            configureButton();
        }

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 10:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                    configureButton();
                return;
        }
    }

    private void configureButton() {
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                locationManager.requestLocationUpdates("gps", 4000, 0, locationListener);
            }
        });

    }
}

Answer 1

嘿，我不确定，但你看起来像这样希望这会对你有所帮助。

  float oldlat, oldlng;
  float currentLat, currentLng;


  // Use this in location changed 
  currentLat = (float) location.getLatitude();
  currentLng = (float) location.getLongitude();

   final Handler handler = new Handler();
   handler.postDelayed(new Runnable() {
   @Override
   public void run() {

        oldlat = (float) location.getLatitude();
        oldlng = (float) location.getLongitude();

   }
   }, 4000);

固定间隔后获取纬度位置

1 个答案: