安卓警报对话框没有显示在仿真器上

Question

我写了代码来检查GPS设置并发出警报对话框，但它并未显示在android模拟器中。

这是用于检查GPS设置并显示警报对话框的代码。

package com.example.user.testlocation; 

    import android.content.DialogInterface; 
    import android.content.Intent; 
    import android.location.LocationManager; 
    import android.provider.Settings; 
    import android.support.v7.app.AlertDialog; 
    import android.support.v7.app.AppCompatActivity; 
    import android.os.Bundle; 

    public class Location extends AppCompatActivity { 


     @Override 
     protected void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.activity_location); 
     } 

     private void isLocationEnalbled(){ 
      LocationManager locationManager=(LocationManager)getSystemService(LOCATION_SERVICE); 
      if(!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)|| !locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)){ 
       AlertDialog.Builder alertDialog=new AlertDialog.Builder(this); 
       alertDialog.setTitle("Enable Location"); 
       alertDialog.setMessage("Your locations setting is not enabled. Please enabled it in settings menu."); 
       alertDialog.setPositiveButton("Location Settings", new DialogInterface.OnClickListener(){ 
        public void onClick(DialogInterface dialog, int which){ 
         Intent intent=new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS); 
         startActivity(intent); 
        } 
       }); 
       alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener(){ 
        public void onClick(DialogInterface dialog, int which){ 
         dialog.cancel(); 
        } 
       }); 
       AlertDialog alert=alertDialog.create(); 
       alert.show(); 
      } 
      else{ 
       AlertDialog.Builder alertDialog=new AlertDialog.Builder(this); 
       alertDialog.setTitle("Confirm Location"); 
       alertDialog.setMessage("Your Location is enabled, please enjoy"); 
       alertDialog.setNegativeButton("Back to interface",new DialogInterface.OnClickListener(){ 
        public void onClick(DialogInterface dialog, int which){ 
         dialog.cancel(); 
        } 
       }); 
       AlertDialog alert=alertDialog.create(); 
       alert.show(); 
      } 
     } 
    } 

它没有显示任何错误，但是当我执行它时不显示警告对话框。

Answer 1

你永远不会打电话isLocationEnalbled()做检查的方法。将此添加到您的课程中，以便每次活动resumed时，应用程序都会检查isLocationEnalbled()。

@Override 
public void onResume() { 
    super.onResume(); 
    isLocationEnalbled(); 
} 

Answer 2

在onCreate（）方法，你必须调用控制的isLocationEnalbled()

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_location); 
     isLocationEnalbled() 
    }