Question

我只是尝试做一个给出当前位置图（经度和纬度值）的应用程序我刚刚创建了一个 GPstracker.java 并在那里使用了操作我只需要获得与按下按钮相关的两个值它对我未来的编码很有帮助我是初学者这是我的主要活动代码

 package com.example.shellz.gps_locator;

   import android.os.Bundle;
   import android.support.design.widget.FloatingActionButton;
   import android.support.design.widget.Snackbar;
   import android.support.v7.app.AppCompatActivity;
   import android.support.v7.widget.Toolbar;
   import android.view.View;
   import android.view.Menu;
   import android.view.MenuItem;
   import android.widget.Button;
   import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

Button btn;
GPStracker gps;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    btn=(Button)findViewById(R.id.location_btn);


    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            gps=new GPStracker(MainActivity.this);
            if(gps.canGetLocation())
            {
                Double latitude=gps.getLatitude();
                Double longitude=gps.getLongitude();
                Toast.makeText(getApplicationContext(),latitude+" and "+longitude+" ",Toast.LENGTH_LONG).show();
            }
            else
            {
                gps.showSettingsAlert();
            }
        }
    });


}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}


@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

}

这是我的 GPStracker.java 这里我做了与我的项目相关的所有操作

   package com.example.shellz.gps_locator;

   import android.Manifest;
   import android.app.AlertDialog;
   import android.app.Service;
   import android.content.Context;
   import android.content.DialogInterface;
   import android.content.Intent;
   import android.content.pm.PackageManager;
   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.support.annotation.Nullable;
   import android.support.v4.app.ActivityCompat;
   import  android.widget.Toast;


public class GPStracker extends Service implements LocationListener {

private static final Location TODO = null;
private final Context mContext;

//gps status
Boolean isGPSEnable = false;

//network status
Boolean isNetwokEnable = false;

Boolean CangetLoaction = false;

Location location;
Double latitude;
Double longitude;

private static final long MIN_DISTANCE_FOR_UPDATE = 10;

private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1;

protected LocationManager locationmanger;

public GPStracker(Context context) {
    this.mContext = context;
    getLocation();
}

public Location getLocation() {
    try {

        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return TODO;
        }

        locationmanger = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);

        isGPSEnable = locationmanger.isProviderEnabled(LocationManager.GPS_PROVIDER);

        isNetwokEnable = locationmanger.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if (!isNetwokEnable && !isGPSEnable) {
            Toast.makeText(getApplicationContext(), "No Network Avialiable", Toast.LENGTH_LONG).show();
        } else {
            this.CangetLoaction = true;
            if (isNetwokEnable) {

                locationmanger.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_FOR_UPDATE, this);
                if (locationmanger != null) {


                    location = locationmanger.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();

                    }
                }
            }
            if (isGPSEnable) {
                locationmanger.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_FOR_UPDATE, this);
                if (locationmanger != null) {


                    location = locationmanger.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();

                    }
                }
            }

        }
    } catch (Exception e) {
        e.printStackTrace();
    }


    return location;
}

public void stopUsingGPS() {
    if (locationmanger != null) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }
        locationmanger.removeUpdates(GPStracker.this);
    }
}

public double getLatitude(){
    if(location != null){
        latitude = location.getLatitude();
    }

    // return latitude
    return latitude;
}

public double getLongitude(){
    if(location != null){
        longitude = location.getLongitude();
    }

    // return longitude
    return longitude;
}

public boolean canGetLocation() {
    return this.canGetLocation();
}

public void showSettingsAlert(){
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

    // Setting Dialog Title
    alertDialog.setTitle("GPS is settings");

    // Setting Dialog Message
    alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

    // On pressing Settings button
    alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog,int which) {
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            mContext.startActivity(intent);
        }
    });

    // on pressing cancel button
    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) {
            dialog.cancel();
        }
    });

    // Showing Alert Message
    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) {

}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

}

这里是我在运行时得到的错误

06-25 17:14:36.296 10750-10750/com.example.shellz.gps_locator E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.StackOverflowError
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.java:147)
at com.example.shellz.gps_locator.GPStracker.canGetLocation(GPStracker.

Answer 1

这是因为函数调用自身。它是一个无限循环。

public boolean canGetLocation() {
    return this.canGetLocation();
}

修改此功能以删除此错误。

这个想你想把它改成：

public boolean canGetLocation() {
        return this.CangetLoaction;
    }

致命异常：主要是java.lang.StackOverflowError

1 个答案: