1

所以我只是想获取用户的位置并在吐司中显示它......但它根本不起作用......我也试图在活动开始时显示吐司但即使在那个时候它也不起作用这是我的代码

package com.example.alert;

import com.example.alert.CurrentLocation.MyLocationListener;

import android.app.Activity;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;


public class ViewAlerters extends Activity{

private Button addButton;
private Button removeButton;
LocationManager lm=(LocationManager)getSystemService(Context.LOCATION_SERVICE);

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view_alerters);
    Toast.makeText( ViewAlerters.this,"Hello",Toast.LENGTH_SHORT).show();

    LocationListener ll=new MyLocationListener();
    //lm.requestLocationUpdates( LocationManager.GPS_PROVIDER, 5*60*10000, 0, ll);
    lm.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, ll);
    setUpViews();

}

private void setUpViews() {
    Toast.makeText( getApplicationContext(),"Hello",Toast.LENGTH_SHORT).show();

    addButton = (Button) findViewById(R.id.add_button);
    //alerterText = (TextView) findViewById(R.id.alert_list_text);
    removeButton = (Button)findViewById(R.id.remove_button);
    addButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            Intent intent = new Intent(ViewAlerters.this,AddAlerter.class);
            startActivity(intent);
        }
    });

}



/* Class My Location Listener */
public class MyLocationListener implements LocationListener
{

    public void onLocationChanged(Location loc)
    {
        if(loc!=null)
        {
            double x;


            String Text = "My current location is: " +"Latitud = " + loc.getLatitude() +"Longitud = " + loc.getLongitude();
        /*  cr.moveToFirst();
            while(!cr.isAfterLast()) {
                 al.add(cr.getString(cr.getColumnIndex(dbAdapter.KEY_NAME))); //add the item
                 cr.moveToNext();
            }*/
        //  lm.addProximityAlert(loc.getLatitude(), loc.getLongitude(), 10009,, intent)

            //for loop, alerters retrieving one by one
//      x= calcDistance(loc.getLatitude(),loc.getLongitude(),z,y);
    //      if(x<1){
        //        Intent myIntent = new Intent(ViewAlerters.this,CallMode.class);
          //        startActivity(myIntent);
            }

        }

    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub
        Toast.makeText( getApplicationContext(),"Gps Disabled - @From :Alert Me",Toast.LENGTH_SHORT ).show();


    }

    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
        Toast.makeText( getApplicationContext(),"Gps Enabled - @From :Alert Me",Toast.LENGTH_SHORT).show();

    }

    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub

    }
    }


public double calcDistance(double latA, double longA, double latB, double longB) {

    double theDistance = (Math.sin(Math.toRadians(latA)) *  Math.sin(Math.toRadians(latB)) + Math.cos(Math.toRadians(latA)) * Math.cos(Math.toRadians(latB)) * Math.cos(Math.toRadians(longA - longB)));
    return new Double((Math.toDegrees(Math.acos(theDistance))) * 69.09*1.6093);
}

}

4

2 回答 2

1

不要使用 getApplicationContext：

Toast.makeText( this,"Hello",Toast.LENGTH_SHORT).show();

请参阅有关Contexts 中的差异的问题：差异以及何时使用 getApplication()、getApplicationContext()、getBaseContext() 和 someClass.this

于 2012-11-10T11:48:27.037 回答
0 
Toast.makeText( ViewAlerters.this,"Hello",Toast.LENGTH_SHORT).show();
于 2014-02-13T06:38:22.670 回答