为什么LocationManager不具有lastKnown位置？

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 maywant 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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