我在将任务从主要的Activity OnCreate方法卸载到另一个类上来进行繁重的工作时遇到了麻烦。
当我尝试从非Activity类调用getSystemService时,将引发异常。
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;
}
}
最佳答案
您需要将上下文传递给Fyl类。
一种解决方案是为fyl
类创建一个类似这样的构造函数:
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 Activity 类中,在
onCreate
函数中创建fyl的对象,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);
}
}