Android 集成GoogleMap,實現定位和獲取位置信息

1.准備

我使用的是AS2.2.2,首先翻牆注冊google開發者帳號,准備獲取API Key,網上有許多相關資料我就不再贅述,這里講一個比較小白級的獲取方法,可以減少許多輸入

1.1. AS創建項目添加一個Google Map Activity

 

1.2 創建成功后找到google_maps_api.xml,便可看到下圖內容,根據我初中英文水平,復制這行到瀏覽器地址欄,跟着它走就行了,記得翻牆

1.3 最后你會看到已經幫你創建好了密鑰,復制到項目中

<string name="google_maps_key" templateMergeStrategy="preserve" translatable="false">YOUR_KEY_HERE</string>

替代即可.

 

1.4 在項目中添加Google Services依賴,我這里選擇的是在build.gradle中添加地圖服務和位置信息服務

compile 'com.google.android.gms:play-services:9.8.0' 
compile 'com.google.android.gms:play-services-location:9.8.0'

2.代碼部分

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap map) {
        // Add a marker in Sydney, Australia, and move the camera.
        LatLng sydney = new LatLng(-34, 151);
        map.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        map.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }
}

在創建好的MapsActivity中,已經有以上代碼,此時運行項目已經可以看到地圖界面並定位到了悉尼

現在添加地圖定位層,由於地圖准備就緒后會調用onMapReady(),我們就在准備就緒后顯示定位層

 /**
     * 如果取得了權限,顯示地圖定位層
     */
    private void enableMyLocation() {
        if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            // Permission to access the location is missing.
            PermissionUtils.requestPermission(this, LOCATION_PERMISSION_REQUEST_CODE,
                    android.Manifest.permission.ACCESS_FINE_LOCATION, true);
        } else if (mMap != null) {
            // Access to the location has been granted to the app.
            mMap.setMyLocationEnabled(true);
        }
    }

那么,顯示出定位層后,如何獲取到位置信息呢,在GoogleMap這個類中沒法獲取到信息的,得通過Google Play services location APIs 來獲取.

這里我推薦一份中文的安卓文檔:http://hukai.me/android-training-course-in-chinese/location/index.html  ,有需要的可以了解到更多關於谷歌位置信息服務知識

我們使用APIs中的fused location provider來獲取設備的最后可知位置,用getLastLocation()方法為設備的位置構造一個單一請求

onConnected()方法會在Google API Client准備好時調用,可以在這里取得地理位置的經度和緯度坐標

public class MainActivity extends ActionBarActivity implements
        ConnectionCallbacks, OnConnectionFailedListener {
    ...
    @Override
    public void onConnected(Bundle connectionHint) {
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);
        if (mLastLocation != null) {
            mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
            mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
        }
    }
}

然而有經緯度是不夠的,還需要將經緯度轉成地理列表,這里使用Geocoder 類的 getFromLocation() 方法接收一個經度和緯度，返回一個地址列表,不過這個操作可能會耗時,所以啟動一個IntentService 處理,這里定義一個繼承 IntentService 的類 FetchAddressIntentService,這個類是地址查找服務.這個類代碼隨后在demo中給,你也可以參考api摸索.

這里講講如何啟動FetchAddressIntentService

public class MainActivity extends ActionBarActivity implements
        ConnectionCallbacks, OnConnectionFailedListener {

    protected Location mLastLocation;
    private AddressResultReceiver mResultReceiver;
    ...

    protected void startIntentService() {
        Intent intent = new Intent(this, FetchAddressIntentService.class);
        intent.putExtra(Constants.RECEIVER, mResultReceiver);     //所需參數一,接收處理結果
        intent.putExtra(Constants.LOCATION_DATA_EXTRA, mLastLocation);    //所需參數二
        startService(intent);
    }
}

必須在 Google Play services 連接穩定之后啟動 intent 服務,所以會在剛剛的onConnected()調用startIntentService()

public class MainActivity extends ActionBarActivity implements
        ConnectionCallbacks, OnConnectionFailedListener {
    ...
    @Override
    public void onConnected(Bundle connectionHint) {
        // Gets the best and most recent location currently available,
        // which may be null in rare cases when a location is not available.
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(    //所需參數二

                mGoogleApiClient);

        if (mLastLocation != null) {
            // Determine whether a Geocoder is available.
            if (!Geocoder.isPresent()) {
                Toast.makeText(this, R.string.no_geocoder_available,
                        Toast.LENGTH_LONG).show();
                return;
            }

            if (mAddressRequested) {
                startIntentService();
            }
        }
    }
}

還缺少參數一,這里通過重寫 onReceiveResult() 方法來處理發送給接收端的結果

 

class AddressResultReceiver extends ResultReceiver {
        public AddressResultReceiver(Handler handler) {
            super(handler);
        }

        @Override
        protected void onReceiveResult(int resultCode, Bundle resultData) {

            // Display the address string
            // or an error message sent from the intent service.
            mAddressOutput = resultData.getString(Constants.RESULT_DATA_KEY);
            displayAddressOutput();

            // Show a toast message if an address was found.
            if (resultCode == Constants.SUCCESS_RESULT) {
                showToast(getString(R.string.address_found));
            }

        }
    }

實例化就能使用了

  mResultReceiver = new AddressResultReceiver(new Handler());

結束,第一次寫,求輕噴,附上Demo

https://github.com/Linyaodai/MyLocationDemo