如何确定GPS位置是否已在android上获取？

Question

比方说，我有一个按钮，只有当系统知道EXACT用户的位置时，才会调用另一个活动。我做了一个对话框，要求用户在禁用GPS时打开GPS，但是当用户启用GPS并再次按下按钮时，我可能还没有确切的位置。谁能帮我这个 ？

Answer 1

您需要创建一个LocationListener并等待回调。它在API docs很好描述：

// Acquire a reference to the system Location Manager 
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE); 

// Define a listener that responds to location updates 
LocationListener locationListener = new LocationListener() { 
    public void onLocationChanged(Location location) { 
    // When you get here you have a location... 
    useTheNewLocationToEnableTheButton(location); 
    } 

    public void onStatusChanged(String provider, int status, Bundle extras) {} 

    public void onProviderEnabled(String provider) {} 

    public void onProviderDisabled(String provider) {} 
}; 

// Register the listener with the Location Manager to receive location updates 
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener); 

Answer 2

如果你不知道坐标，最好的办法是在检索一个位置时显示一个ProgressDialog，当你得到它时，关闭ProgressDialog并启动你的活动。

final LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE); 
LocationListener locationListener = new LocationListener() { 
    public void onLocationChanged(Location location) { 
    //here you can get coordinates via location.getLongitude() and 
    //location.getLatitude() methods, dismiss the progress dialog and 
    //start your activity 
    locationManager.removeUpdates(this); 
    } 
    public void onStatusChanged(String provider, int status, Bundle extras) {} 
    public void onProviderEnabled(String provider) {} 
    public void onProviderDisabled(String provider) {} 
}; 
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener); 

Answer 3

您可以侦听GpsStatus事件，以确保用户实际启用GPS（GPS_EVENT_STARTED），并且当GPS获得位置定位通知（GPS_EVENT_FIRST_FIX）。