为什么LocationManager不具有lastKnown位置？ [英] Why does the LocationManager does not have a lastKnown location?

问题描述

我想用户的位置，而且也只有一次之后，该用户导航在自己的

I want the location of user and that too just once after that user navigates on his own

locationManager = (LocationManager)this.getSystemService(LOCATION_SERVICE);
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER); 
if (location != null) {
   System.out.println(location.toString());
   lat=location.getLatitude();
   lng=location.getLongitude();
}     
p = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6));

但是我不能够获取用户的位置，是因为从移动??

However i am not able to get the location of the user is it because of slow internet connection from the mobile ??

推荐答案

这是不够的，只是得到一个locationManager并调用 getLastKnownLocation（） 因为直到有更新就没有最后已知位置 你缺少的LocationManager类提供的这一要求：

It's not enough to just get a locationManager and call getLastKnownLocation() because until there is an update there will be no "last known location" You are missing that request provided by the LocationManager class:

public void requestLocationUpdates(java.lang.String provider, 
                                   long minTime,
                                   float minDistance, 
                                   android.location.LocationListener listener) 

如果你的活动实现LocationListener的矿山一样，你可以通过在本的LocationListener的一个呼叫始发的那个类的方法。否则，有服用活动或尺蠖类，而不是其他一些重载。

If your activity implements LocationListener as mine did, you can pass in "this" as the LocationListener for a call originating in a method of that class. Otherwise, there are several other overloads taking Activity or Looper classes instead.

locationManager.requestLocationUpdates(provider, minTime, minDistance, this);

为了确保该设备得到一个位置，要求更新 - 但你也可以 希望把警卫未能找到提供者或 getLastKnownLocation 返回null。

In order to make sure the device is getting a location, request updates - but you also may want to put guards for failure to find providers or getLastKnownLocation returning null.

locationManager.requestLocationUpdates(provider, 1, 0, this);
mostRecentLocation = locationManager.getLastKnownLocation(provider);
if(mostRecentLocation == null)
// lower your expectations, or send user message with Toast or something similar 

告诉用户打开其位置共享或其他供应商的服务。

Tell the user to turn on their location sharing or other provider services.

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