我正在试验 android 开发,并获取设备的位置。
下面列出了我的 GPSTracker 类并抛出了错误。
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
/**
* Created by informationservices on 29/08/14.
*/
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
//flag for GPS status
boolean isGPSEnabled = false;
//flag for network status
boolean isNetworkEnabled = false;
boolean canGetLocation = false;
Location location;
double latitude; //latitude variable
double longitude; //longitude variable
//The minimum distance to change updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1;
private static final long MIN_TIME_BW_UPDATES = 1000;
//declare location manager
protected LocationManager locationManager;
public GPSTracker(Context context){
this.mContext = context;
getLocation();
}
//function to get latitude
public double getLatitude(){
if (location != null){
latitude = location.getLatitude();
}
//must have a return (as its a function)
return latitude;
}
public double getLongitude(){
if (location !=null){
longitude = location.getLongitude();
}
return longitude;
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
//getting GPS Status
isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
//getting Network Status
isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
//No Network provider is enabled
}else{
this.canGetLocation=true;
//first get location from Network Provider
if(isNetworkEnabled){
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,MIN_TIME_BW_UPDATES,MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager !=null){
location=locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if(location !=null){
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
catch (Exception e){
e.printStackTrace();
}
return location;
}
//check if this is the best network provider
public boolean canGetLocation(){
return this.canGetLocation;
}
//show GPs settings in alert box
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog(mContext);//AlertDialog(android.content.Context) has protected access in 'android.app.AlertDialog'
//set alert title
alertDialog.setTitle("GPS is Settings");
//set Dialog message
alertDialog.setMessage("GPS is not Enabled. Do you want to go to settings menu?");
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivities(new Intent[]{intent});
}
});
alertDialog.setNegativeButton("Cancel",new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
dialog.cancel();
}
});
//show alert
alertDialog.show();
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
这是我第一次尝试为 android 编写代码。我已经用谷歌搜索了一段时间,但不明白为什么会抛出这个错误。
谁能解释一下这个错误的含义,以及如何修复它。
也将不胜感激详尽的解释,以及指向任何相关谷歌文档的链接。
最佳答案
该错误意味着 AlertDialog 构造函数不可访问(公共(public))。它被声明为 protected ,因此程序员在使用 AlertDialogs 时被迫使用构建器模式。
要显示 AlertDialog,您可以使用 AlertDialog.Builder 设置所有内容,然后调用 show() 来构建和显示 AlertDialog。
// Use the AlertDialog.Builder to configure the AlertDialog.
AlertDialog.Builder alertDialogBuilder =
new AlertDialog.Builder(this)
.setTitle("GPS is Settings")
.setMessage("GPS is not Enabled. Do you want to go to settings menu?")
.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivities(new Intent[]{intent});
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Show the AlertDialog.
AlertDialog alertDialog = alertDialogBuilder.show();
关于android - 警报对话已保护访问权限,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25560408/