Gps android - 获取纬度和经度

Posted 2023-02-23

【中文标题】Gps android - 获取纬度和经度

【英文标题】：Gps android - getting Latitude and Longitude

【发布时间】：2011-05-23 17:55:52

【问题描述】：

你能帮我解决这个问题吗.. 当我添加地理编码器以使用纬度和经度获取城市名称时，应用程序开始崩溃..

    double latitude, longitude;
    private TextView lala;

    LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 
    Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
    longitude = location.getLongitude();
    latitude = location.getLatitude();
    final LocationListener locationListener = new LocationListener() 
        public void onLocationChanged(Location location) 
            longitude = location.getLongitude();
            latitude = location.getLatitude();
        

        public void onProviderDisabled(String arg0) 
            // TODO Auto-generated method stub

        

        public void onProviderEnabled(String arg0) 
            // TODO Auto-generated method stub

        

        public void onStatusChanged(String arg0, int arg1, Bundle arg2) 
            // TODO Auto-generated method stub

        
    ;

    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
    lala = (TextView) findViewById(R.id.textView1);

    Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());   
    List<Address> myList = null;
    try 
        myList = myLocation.getFromLocation(latitude, longitude, 1);
     catch (IOException e1) 
        // TODO Auto-generated catch block
        e1.printStackTrace();
    


    lala.setText((CharSequence) myList);

【参考方案1】：

lm.getLastKnownLocation 可以返回 null，然后你尝试getLongitude() 你会得到NullPointerException

lala.setText((CharSequence) myList); 也可以做同样的事情（抛出异常），因为这里的 myList 可以为空（如果 Geocoder 失败）。

编辑 要处理 Geocoder 中的异常，请考虑以下清单

确保您的纬度和经度不为空 确保 -90 确保您有可用的网络连接

EDIT2 改进的代码

private TextView lala;

LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 
Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);

if(location != null) 
    showMyAddress(location);


final LocationListener locationListener = new LocationListener() 
    public void onLocationChanged(Location location) 
        showMyAddress(location);
    

    public void onProviderDisabled(String arg0) 
        // TODO Auto-generated method stub

    

    public void onProviderEnabled(String arg0) 
        // TODO Auto-generated method stub

    

    public void onStatusChanged(String arg0, int arg1, Bundle arg2) 
        // TODO Auto-generated method stub

    
;

lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
lala = (TextView) findViewById(R.id.textView1);



// Also declare a private method

private void showMyAddress(Location location) 
    double latitude = location.getLatitude();
    double longitude = location.getLongitude();
    Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());   
    List<Address> myList;
    try 
        myList = myLocation.getFromLocation(latitude, longitude, 1);
        if(myList.size() == 1) 
            lala.setText(myList.get(0).toString());             
        
     catch (IOException e1) 
        // TODO Auto-generated catch block
        e1.printStackTrace();
    

【讨论】：

你是对的..但是你能告诉我该怎么做才能使 Geocoder 不会失败.. 对不起，我是 android 和 java 的初学者..

okey.. 现在我有纬度：59.412.. 和经度：24.689.. 而且我的网络连接工作正常.. 也许我的代码有问题

是的，我又发现了一个错误 - 您正在将 List 转换为 CharSequence，这是无法完成的。请参阅我的第二次编辑。

好吧...你是我的救命恩人...谢谢

【参考方案2】：

Criteria criteria = new Criteria();
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
String provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
int la = (int) (location.getLatitude() * 1E6);
int lo = (int) (location.getLongitude() * 1E6);