如何在非活动类 (LocationManager) 中使用 getSystemService？

小编典典

如何在非活动类 (LocationManager) 中使用 getSystemService？

all

我无法将主要活动 OnCreate 方法中的任务卸载到另一个类来完成繁重的工作。

当我尝试从非 Activity 类调用 getSystemService 时，会引发异常。

任何帮助将不胜感激：）

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;
    }
}

阅读 61

2022-06-29

共1个答案

小编典典

您需要将您的上下文传递给您的 fyl 类。
一种解决方案是为您的fyl类创建一个这样的构造函数：

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

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

       --
 }
}

因此，在您的活动类中，在函数中创建 fyl 的对象，onCreate如下所示：

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);
    }
}

2022-06-29