static final String TAG = "MainActivity";
 
 
 private TextView locationTV;
 private LocationManager locationManager;
 private String provider;
 
 ArrayList<ContactModel> dataList = new ArrayList<ContactModel>();
 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
//  initView();
 
 
  locationTV = (TextView) findViewById(R.id.locaiton_tv);
 
  locationManager = (LocationManager) getSystemService(this.LOCATION_SERVICE);
  // 獲取所有可用的位置提供器
  List<String> providerList = locationManager.getProviders(true);
  if (providerList.contains(LocationManager.GPS_PROVIDER)) {
   provider = LocationManager.GPS_PROVIDER;
  } else if (providerList.contains(LocationManager.NETWORK_PROVIDER)) {
   provider = LocationManager.NETWORK_PROVIDER;
  } else {
   // 當沒有可用的位置提供器時，彈出Toast提示用戶
   Toast.makeText(this, "No location provider to use", Toast.LENGTH_SHORT).show();
   return;
  }
  Location location = locationManager.getLastKnownLocation(provider);
  if (location != null) {
   // 顯示當前設備的位置信息
   showLocation(location);
  }
  if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.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;
  }
  locationManager.requestLocationUpdates(provider, 5000, 1, locationListener); 
 }
 private void showLocation(Location location) {
  String currentPosition = "latitude is " + location.getLatitude() + "\n"+ "longitude is " + location.getLongitude();
  locationTV.setText(currentPosition);
 }
 
 @Override
 protected void onDestroy() {
  super.onDestroy();
 
  if (locationManager != null) {
 
   if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.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;
   }
 
 
   // 關閉程序時將監聽器移除
   locationManager.removeUpdates(locationListener);
  }
 }
 
 LocationListener locationListener = new LocationListener() {
  @Override
  public void onLocationChanged(Location location) {
 
   Toast.makeText(MainActivity.this,"onLocationChanged",Toast.LENGTH_SHORT).show();
  }
 
  @Override
  public void onStatusChanged(String s, int i, Bundle bundle) {
   Toast.makeText(MainActivity.this,"onStatusChanged",Toast.LENGTH_SHORT).show();
  }
 
  @Override
  public void onProviderEnabled(String s) {
   Toast.makeText(MainActivity.this,"onProviderEnabled",Toast.LENGTH_SHORT).show();
  }
 
  @Override
  public void onProviderDisabled(String s) {
   Toast.makeText(MainActivity.this,"onProviderDisabled",Toast.LENGTH_SHORT).show();
  }
 };