计算在android中移动的距离（移动时）

海我需要在自行车正在移动时使用GPS在android中计算距离。同时我给模拟器中的经纬度值提供正确的值，但通过使用设备的分组数据并运行应用程序，这些值不会发生任何变化。这是代码，请建议。计算在android中移动的距离（移动时）

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     //locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
     showCurrentLocation(); 
     b2=(Button)findViewById(R.id.button2); 
     b2.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       clearButton(); 
      } 
    });  
    } 

    @SuppressWarnings("unused") 
    protected void showCurrentLocation() { 
     // Getting LocationManager object 
     locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
     // Creating an empty criteria object 
     Criteria criteria = new Criteria(); 
     // Getting the name of the provider that meets the criteria 
     provider = locationManager.getBestProvider(criteria, false); 

     if (provider != null && !provider.equals("")) { 
      Location location = locationManager.getLastKnownLocation(provider); 

      locationManager.requestLocationUpdates(provider, 20000, 1, this); 
      clat = location.getLatitude(); 
      clon = location.getLongitude(); 
      a[0] = clat; 
      a[1] = clon; 

      if (location != null) 
       onLocationChanged(location); 
      else 
       Toast.makeText(getBaseContext(), "Location can't be retrieved", 
         Toast.LENGTH_SHORT).show(); 

     } else { 
      Toast.makeText(getBaseContext(), "No Provider Found", 
        Toast.LENGTH_SHORT).show(); 
     } 
    } 

    @Override 
    public void onLocationChanged(Location location) { 
     // Getting reference to TextView tv_longitude 
     locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
     // Creating an empty criteria object 
     Criteria criteria = new Criteria(); 
     // Getting the name of the provider that meets the criteria 
     provider = locationManager.getBestProvider(criteria, false); 

     if (provider != null && !provider.equals("")) { 
      // Get the location from the given provider 
      Location location1 = locationManager.getLastKnownLocation(provider); 
      locationManager.requestLocationUpdates(provider, 20000, 1, this); 
      plat = location.getLatitude(); 
      plon = location.getLongitude(); 
      a[2] = plat; 
      a[3] = plon; 
      if(a[0]!=a[2]||a[1]!=a[3]) 
     { 
       dis += getDistance(a); 
     } 

      a[0] = plat; 
      a[1] = plon; 
      Log.e("aa", String.valueOf(dis)); 
      TextView tvDistance = (TextView) findViewById(R.id.textView1); 
      tvDistance.setText(String.valueOf(dis) + " km"); 
     } 
    } 
    public double getDistance(double a[]) { 
    double earthRadius = 6371; //kilometers 
    double dLat = Math.toRadians(a[2] -a[0]); 
    double dLng = Math.toRadians(a[3] -a[1]); 
    double b = Math.sin(dLat/2) * Math.sin(dLat/2) + 
       Math.cos(Math.toRadians(a[0])) * Math.cos(Math.toRadians(a[2])) * 
       Math.sin(dLng/2) * Math.sin(dLng/2); 
    double c = 2 * Math.atan2(Math.sqrt(b), Math.sqrt(1-b)); 
    float dist = (float) (earthRadius * c); 

    return dist; 
    } 

    protected void clearButton(){ 
     dis=0; 
     showCurrentLocation(); 
    }

来源

2014-09-25 akhila

嗨，您正在使用getLastKnownLocation（）。有一段时间它会给出无效/错误的位置对，因为它会从最后更新的地方获取......并且更好的方法是使用googleplayservices库。它会帮助你获得移动速度和准确的位置。您可以使用谷歌距离api找到当前和指定位置之间的距离 – Sivakumar 2014-09-25 08:54:43

googleplayservices lib防止部署到诺基亚，亚马逊和其他不是谷歌Android设备。我想知道你所说的bug是否是g所要求的。 – Benoit 2014-09-25 09:03:26

@akhila我面临同样的问题。你有解决方案吗？.. – 2016-01-21 10:55:16

你可以做的步骤，并呼吁getDistance的不是时候的位置是不同的，但在经过时间是相关的自行车速度（1秒？）。

private long timestamp = 0; 

public double getDistance(double a[]) { 
    timestamp = System.currentTimeMillis(); 
    (....) 
} 


public void onLocationChanged(Location location) { 
    (...) 
    if(System.currentTimeMillis() - timestamp > 1000){ 
      dis += getDistance(a); 
    }

来源

2014-09-25 09:01:29 Benoit

计算在android中移动的距离（移动时）

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