我怎样才能在非活动类（LocationManager）使用getSystemService？

问题描述

我无法从主活动卸载任务onCreate方法到另一个类做繁重的任务。

当我尝试从一个异常被抛出非Activity类调用getSystemService。

任何帮助将是很大的AP preciated：）

lmt.java：

 包com.atClass.lmt;
进口android.app.Activity;
进口android.os.Bundle;
进口android.widget.TextView;
进口android.location.Location;

公共类LMT延伸活动{
    @覆盖
    公共无效的onCreate（包savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.main）;

        五年之后lfyl =新的五年之后（）;
        位置位置= lfyl.getLocation（）;
        串latLongString = lfyl.updateWithNewLocation（位置）;

        TextView的myLocationText =（TextView中）findViewById（R.id.myLocationText）;
        myLocationText.setText（您当前的位置是：\ N+ latLongString）;
    }
}
 

fyl.java

 包com.atClass.lmt;

进口android.app.Activity;
进口android.os.Bundle;
进口android.location.Location;
进口android.location.LocationManager;
进口android.os.Bundle;
进口android.widget.TextView;
进口android.content.Context;

公共类五年之后{
    公共场所的getLocation（）{
        LocationManager locationManager;
        字符串情形= Context.LOCATION_SERVICE;
        locationManager =（LocationManager）getSystemService（上下文）;

        字符串提供商= LocationManager.GPS_PROVIDER;
        位置位置= locationManager.getLastKnownLocation（供应商）;

        返回的位置;
    }

    公共字符串updateWithNewLocation（位置定位）{
        字符串latLongString;

        如果（位置！= NULL）{
            双纬度= location.getLatitude（）;
            双LNG = location.getLongitude（）;
            latLongString =纬度：+纬度+\ nLong：+ LNG;
        }其他{
            latLongString =没有位置;
        }

        返回latLongString;
    }
}
 

解决方案

您需要将您的上下文传递给你五年之后类..
一个解决办法是让这样的构造你的五年之后类：

 公共类五年之后{
 语境mContext;
 公共五年之后（上下文mContext）{
       this.mContext = mContext;
 }

 公共场所的getLocation（）{
        -
       locationManager =（LocationManager）mContext.getSystemService（上下文）;

        -
 }
}
 

因此​​，在您的活动类中创建五年之后在这样的的onCreate 函数的对象：

 包com.atClass.lmt;
进口android.app.Activity;
进口android.os.Bundle;
进口android.widget.TextView;
进口android.location.Location;

公共类LMT延伸活动{
    @覆盖
    公共无效的onCreate（包savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.main）;

        五年之后lfyl =新的五年之后（本）; //这里上下文被传递

        位置位置= lfyl.getLocation（）;
        串latLongString = lfyl.updateWithNewLocation（位置）;

        TextView的myLocationText =（TextView中）findViewById（R.id.myLocationText）;
        myLocationText.setText（您当前的位置是：\ N+ latLongString）;
    }
}
 

I'm having trouble offloading tasks from the main Activities OnCreate method onto another class to do the heavy lifting.

When I try to call getSystemService from the non-Activity class an exception is thrown.

Any help would be greatly appreciated :)

lmt.java:

package com.atClass.lmt;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.location.Location;

public class lmt extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        fyl lfyl = new fyl();
        Location location = lfyl.getLocation();
        String latLongString = lfyl.updateWithNewLocation(location);

        TextView myLocationText = (TextView)findViewById(R.id.myLocationText);
        myLocationText.setText("Your current position is:\n" + latLongString);
    }
}

fyl.java

package com.atClass.lmt;

import android.app.Activity;
import android.os.Bundle;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;
import android.content.Context;

public class fyl {
    public Location getLocation(){
        LocationManager locationManager;
        String context = Context.LOCATION_SERVICE;
        locationManager = (LocationManager)getSystemService(context);

        String provider = LocationManager.GPS_PROVIDER;
        Location location = locationManager.getLastKnownLocation(provider);

        return location;
    }

    public String updateWithNewLocation(Location location) {
        String latLongString;

        if (location != null){
            double lat = location.getLatitude();
            double lng = location.getLongitude();
            latLongString = "Lat:" + lat + "\nLong:" + lng;
        }else{
            latLongString = "No Location";
        }

        return latLongString;
    }
}

解决方案

You need to pass your context to your fyl class..
One solution is make a constructor like this for your fyl class:

public class fyl {
 Context mContext;
 public fyl(Context mContext) {
       this.mContext = mContext;
 }

 public Location getLocation() {
       --
       locationManager = (LocationManager)mContext.getSystemService(context);

       --
 }
}

So in your activity class create the object of fyl in onCreate function like this:

package com.atClass.lmt;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.location.Location;

public class lmt extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        fyl lfyl = new fyl(this); //Here the context is passing

        Location location = lfyl.getLocation();
        String latLongString = lfyl.updateWithNewLocation(location);

        TextView myLocationText = (TextView)findViewById(R.id.myLocationText);
        myLocationText.setText("Your current position is:\n" + latLongString);
    }
}

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