gps example in android (안드로이드에서 gps 사용하기 예제)

Android GPS, location manager

기본 소스는 아래 링크를 참고하였습니다.
http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial/
그러나 소스가 오래된거라 빌드가 안되어서 약간 손 본 부분과 분석하기위한 로그를 추가하였습니다.

GPSTracker.java 예제는 service를 상속 받았지만 실제 구현은 Service형태의 예제는 아니고 Activity를 종료시키면 같이 종료되는 형태로 작업이 되었습니다.

아래 예제는 LocationListener의 onLocationChanged, onProviderDisabled, onProviderEnabled, onStatusChanged 의 의미와 발생에 대해서 알아보도록 하겠습니다.

아래 소스는 Android 6.0 M OS 에서 테스트 되었습니다.

0. 전체적인 이해

https://developer.android.com/guide/topics/location/strategies.html

1. 권한

ACCESS_FINE_LOCATION(android.permission.ACCESS_FINE_LOCATION) 권한이 필요합니다. 이 권한은 GPS로 부터 정확한 위치를 얻기위한 것입니다.
ACCESS_COARSE_LOCATION 은 네트워크로부터 위치를 얻기위한 permission인데 FINE location 권한을 획득하면 포함하게됩니다.

Main 소스에서는 아래와 같은 runtime permission을 획득 하도록 하였습니다.

        if ( Build.VERSION.SDK_INT >= 23 &&
                ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
            ActivityCompat.requestPermissions( this, new String[] {  android.Manifest.permission.ACCESS_FINE_LOCATION  },
                    0 );
        }

AndroidManifest.xml

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

2. Provider
위치 정보를 주는 곳이 두군데 있습니다.
위성을 이용하는 방식이 GPS_PROVIDER 이고 Network을 이용하는게 NETWORK_PROVIDER 입니다.
location manager 서비스를 이용해서 위치가 변경되거나 또는 주기적으로 위치정보가 업데이트 될때 정보를 보내도록 요청합니다.
해당코드는 아래와 같습니다. 이때 어떤 provider를 사용할지 인자로 넘기게 됩니다.

Network provider

locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

GPS provider

locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

그외에 인자로 넘어가는 아래값은 언제 업데이트 할지를 결정하는 인자입니다. 해당값에 따라서 거리가 변경되거나 일정 시간이 흐르거나 하면 위치정보를 받을 수 있습니다.

    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

지금 당장 위치를 구하려고 한다면 location provider의 마지막 location 정보를 이용해서 현재 좌표를 얻기위한 방법입니다.

                            location = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (location != null) {
                                latitude = location.getLatitude();
                                longitude = location.getLongitude();
                            }

이후로는 주기적으로 아래 listener로 함수가 호출됩니다.

    @Override
    public void onLocationChanged(Location location) {
        if(location != null){
            double latitude= location.getLatitude();
            double longitude = location.getLongitude();
            //Toast.makeText(mContext, "onLocationChanged is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_SHORT).show();
            sendString("onLocationChanged is - \nLat: " + latitude + "\nLong: " + longitude + " provider:"+location.getProvider()+" mock:"+location.isFromMockProvider());
        }
    }

Provider enable disable 은 설정에서 provider 설정을 변경하면 호출됩니다.
여기에서는 GPS update설정을 변경하도록 구현하였습니다.

    @Override
    public void onProviderDisabled(String provider) {
        //Toast.makeText(mContext, "onProviderDisabled " + provider, Toast.LENGTH_SHORT).show();
        mHandler.sendEmptyMessage(MainActivity.RENEW_GPS);
        sendString( "onProviderDisabled " + provider);
    }

    @Override
    public void onProviderEnabled(String provider) {
        //Toast.makeText(mContext, "onProviderEnabled " + provider, Toast.LENGTH_SHORT).show();
        mHandler.sendEmptyMessage(MainActivity.RENEW_GPS);
        sendString( "onProviderEnabled " + provider);
    }

뒤쪽 provider의 String은 gps, network 등이 출력됩니다. 아래 참고

참고로 location.isFromMockProvider 값을 출력해봤습니다. mock 위치라고 해서 GPS조작앱을 통한 값인지 여부를 판단할 수 있을지 알았는데요.
조작앱을 설치해서 실제 테스트해보니 항상 false값이 확인이 됩니다.
이 부분은 fake GPS 앱들이 특수한 방법으로 true가 안되게 하는것 같습니다. 기회가 닿으면 따로 분석 해보도록 하겠습니다.
http://swlock.blogspot.com/2017/02/using-mock-gps-mock-gps-gps-in-android.html

소스에서 onLocationChanged 될때 Bundle 값을 출력시켜 봤는데요.
satellites 숫자가 나오는데 이건 위성의 숫자라고 합니다.

3. 전체 소스는 아래와 같습니다.

MainActivity

package com.example.xxxx.gpstest;

import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.text.SimpleDateFormat;
import java.util.Date;

// http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial/

public class MainActivity extends AppCompatActivity {
    Button btnShowLocation;
    EditText editText;

    // GPSTracker class
    GPSTracker gps = null;

    public Handler mHandler;

    public static int RENEW_GPS = 1;
    public static int SEND_PRINT = 2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        if ( Build.VERSION.SDK_INT >= 23 &&
                ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
            ActivityCompat.requestPermissions( this, new String[] {  android.Manifest.permission.ACCESS_FINE_LOCATION  },
                    0 );
        }

        editText = (EditText) findViewById(R.id.editText);
        btnShowLocation = (Button) findViewById(R.id.btnShowLocation);

        mHandler = new Handler(){
            @Override
            public void handleMessage(Message msg){
                if(msg.what==RENEW_GPS){
                    makeNewGpsService();
                }
                if(msg.what==SEND_PRINT){
                    logPrint((String)msg.obj);
                }
            }
        };

        // show location button click event
        btnShowLocation.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                // create class object
                if(gps == null) {
                    gps = new GPSTracker(MainActivity.this,mHandler);
                }else{
                    gps.Update();
                }

                // check if GPS enabled
                if(gps.canGetLocation()){
                    double latitude = gps.getLatitude();
                    double longitude = gps.getLongitude();
                    // \n is for new line
                    Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
                }else{
                    // can't get location
                    // GPS or Network is not enabled
                    // Ask user to enable GPS/network in settings
                    gps.showSettingsAlert();
                }
            }
        });
    }
    public void makeNewGpsService(){
        if(gps == null) {
            gps = new GPSTracker(MainActivity.this,mHandler);
        }else{
            gps.Update();
        }

    }
    public void logPrint(String str){
        editText.append(getTimeStr()+" "+str+"\n");
    }
    public String getTimeStr(){
        long now = System.currentTimeMillis();
        Date date = new Date(now);
        SimpleDateFormat sdfNow = new SimpleDateFormat("MM/dd HH:mm:ss");
        return sdfNow.format(date);
    }
}

GPSTracker.java

package com.example.xxxx.gpstest;

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.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.widget.Toast;

import java.util.Set;

/**
 * Created by xxxx on 2017-02-04.
 */
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;

    // flag for GPS status
    boolean canGetLocation = false;

    Location location; // location
    double latitude; // latitude
    double longitude; // longitude

    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

    // Declaring a Location Manager
    protected LocationManager locationManager;

    private Handler mHandler;

    public GPSTracker(Context context, Handler handler) {
        this.mContext = context;
        this.mHandler = handler;
        getLocation();
    }
    public void Update(){
        getLocation();
    }
    public Location getLocation() {

        if ( Build.VERSION.SDK_INT >= 23 &&
                ContextCompat.checkSelfPermission( mContext, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
            return null;
        }
        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();
                        }
                    }
                }
                // if GPS Enabled get lat/long using GPS Services
                if (isGPSEnabled) {
                    if (location == null) {
                        locationManager.requestLocationUpdates(
                                LocationManager.GPS_PROVIDER,
                                MIN_TIME_BW_UPDATES,
                                MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                        Log.d("GPS Enabled", "GPS Enabled");
                        if (locationManager != null) {
                            location = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                            if (location != null) {
                                latitude = location.getLatitude();
                                longitude = location.getLongitude();
                            }
                        }
                    }
                }
            }

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

        return location;
    }

    /**
     * Stop using GPS listener
     * Calling this function will stop using GPS in your app
     * */
    public void stopUsingGPS(){
        if ( Build.VERSION.SDK_INT >= 23 &&
                ContextCompat.checkSelfPermission( mContext, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
            return;
        }
        if(locationManager != null){
            locationManager.removeUpdates(GPSTracker.this);
        }
    }

    /**
     * Function to get latitude
     * */
    public double getLatitude(){
        if(location != null){
            latitude = location.getLatitude();
        }

        // return latitude
        return latitude;
    }

    /**
     * Function to get longitude
     * */
    public double getLongitude(){
        if(location != null){
            longitude = location.getLongitude();
        }

        // return longitude
        return longitude;
    }

    /**
     * Function to check GPS/wifi enabled
     * @return boolean
     * */
    public boolean canGetLocation() {
        return this.canGetLocation;
    }

    /**
     * Function to show settings alert dialog
     * On pressing Settings button will lauch Settings Options
     * */
    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) {
        if(location != null){
            double latitude= location.getLatitude();
            double longitude = location.getLongitude();
            //Toast.makeText(mContext, "onLocationChanged is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_SHORT).show();
            sendString("onLocationChanged is - \nLat: " + latitude + "\nLong: " + longitude + " provider:"+location.getProvider()+" mock:"+location.isFromMockProvider());
        }
    }

    @Override
    public void onProviderDisabled(String provider) {
        //Toast.makeText(mContext, "onProviderDisabled " + provider, Toast.LENGTH_SHORT).show();
        mHandler.sendEmptyMessage(MainActivity.RENEW_GPS);
        sendString( "onProviderDisabled " + provider);
    }

    @Override
    public void onProviderEnabled(String provider) {
        //Toast.makeText(mContext, "onProviderEnabled " + provider, Toast.LENGTH_SHORT).show();
        mHandler.sendEmptyMessage(MainActivity.RENEW_GPS);
        sendString( "onProviderEnabled " + provider);
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        //Toast.makeText(mContext, "onStatusChanged " + provider + " : " + status, Toast.LENGTH_SHORT).show();
        mHandler.sendEmptyMessage(MainActivity.RENEW_GPS);
        sendString("onStatusChanged " + provider + " : " + status + ":" + printBundle(extras));
    }

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    private void sendString(String str){
        Message msg = mHandler.obtainMessage();
        msg.what = MainActivity.SEND_PRINT;
        msg.obj = new String(str);
        mHandler.sendMessage(msg);
    }

    public static String printBundle(Bundle extras) {
        StringBuilder sb = new StringBuilder();
        try {
                sb.append("extras = " + extras);
                sb.append("\n");
                if (extras != null) {
                    Set keys = extras.keySet();
                    sb.append("++ bundle key count = " + keys.size());
                    sb.append("\n");

                    for (String _key : extras.keySet()) {
                        sb.append("key=" + _key + " : " + extras.get(_key)+",");
                    }
                    sb.append("\n");
                }
        } catch (Exception e) {

        } finally {

        }
        return sb.toString();
    }

}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.xxxx.gpstest">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
</manifest>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.darts.gpstest.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="START"
        android:id="@+id/btnShowLocation"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/editText"
        android:layout_below="@+id/btnShowLocation"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentEnd="true"
        android:editable="false"
        android:textSize="10dp"
        android:text="log print here\n" />
</RelativeLayout>

소스
https://drive.google.com/open?id=0B9vAKDzHthQIenZKLU1JeV9SY2c

APK
https://drive.google.com/open?id=0B9vAKDzHthQIOWhydXRGTjV6cWs