仍然是相对较新的我在查找我在活动类MainActivity中使用的非活动类MyLocation中遇到问题时遇到了问题.我正在使用MyLocation来获取经度和纬度.
我想在使用GPS或网络时突出显示文本视图.为此,我需要在非活动类MyLocation中查找textviews.
我想在使用GPS或网络时突出显示文本视图.为此,我需要在非活动类MyLocation中查找textviews.
public class MainActivity extends ActionBarActivity implements LocationListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MyLocation myLocation = new MyLocation();
myLocation.getLocation(this,locationResult);
}
在这里我在MyLocation中尝试查找textviews：
public class MyLocation {
LocationManager lm;
LocationResult locationResult;
private Context context;
TextView tvnetwork,tvgps;
private int defaultTextColor;
LocationListener locationListenerNetwork = new LocationListener() {
public void onLocationChanged(Location location) {
locationResult.gotLocation(location);
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = inflater.inflate(R.layout.main,null);
tvnetwork = (TextView) v.findViewById(R.id.tvnetwork);
tvgps = (TextView) v.findViewById(R.id.tvgps);
defaultTextColor = tvgps.getTextColors().getDefaultColor();
tvnetwork.setTextColor(context.getResources().getColor(
R.color.green));
tvgps.setTextColor(defaultTextColor);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerGps);
}
public void onProviderDisabled(String provider) {
}
public void onProviderEnabled(String provider) {
}
public void onStatusChanged(String provider,int status,Bundle extras) {
}
};
但没有找到意见.我已经获得了NPE @ .getSystemService(Context.LAYOUT_INFLATER_SERVICE);.我究竟做错了什么？
解决方法
get a NPE @ .getSystemService(Context.LAYOUT_INFLATER_SERVICE);. What
am I doing wrong?
因为MyLocation类中的上下文为null.使用MyLocation类构造函数在MyLocation中传递MainActivity上下文以访问系统服务：
Activity activity;
public MyLocation(Context context,Activity activity){
this.context=context;
this.activity=activity;
}
并在MainActivity中通过将MainActivity上下文传递为：创建MyLocation类对象：
MyLocation myLocation = new MyLocation(MainActivity.this,this);
现在使用上下文访问MyLocation类中的系统服务
编辑：而不是在onLocationChanged中再次膨胀主布局使用Activity上下文从Activity Layout访问视图：
public void onLocationChanged(Location location) {
....
tvnetwork = (TextView) activity.findViewById(R.id.tvnetwork);
tvgps = (TextView) activity.findViewById(R.id.tvgps);
defaultTextColor = tvgps.getTextColors().getDefaultColor();
tvnetwork.setTextColor(context.getResources().getColor(
R.color.green));
tvgps.setTextColor(defaultTextColor);
....
}
