對《第一行代碼---Android》的學習筆記
基于位置的服務簡介
基于位置服務簡稱LBS,主要工作原理就是利用無線電通訊網絡GPs等定位方式确定移動位置的所在。
找到自己的位置
android使用LocationManager類實作
首先擷取執行個體
LocationManager locationManager=(~)getSystemSeriver(Context.LOACTION_SERVICE);
然後需要選擇一個位置提供器來确定裝置的分目前位置。
Android提供了三種位置提供器可供選擇:1.GPS——PROVIDER2.NETWORK_PROVIDER 3.PASSIVE_PROVIDER.
其中前兩種使用的比較多,分别表示GPS定位和使用網絡定位,前者定位的精準度比較高,但是非常耗電,而網絡定位的精準度比較低,但耗電少。
将選擇好的位置提供器傳入到getLastKnownLocation()方法中,就可以得到一個Location對象
String provider=LocationManager.NETWORK_PROVIDER;
Location location=locationManager.getLastKnownLocation(provider);
這個Location對象中包含了經緯度,海拔等一系列的位置資訊,然後從中提取我們需要的資訊即可
如果有些時候你想讓定位的精度更精确一點,但又不确定GPS定位的功能是否已經啟用,這個時候就可以判斷一下有哪些位置提供器
List<String>providerList=locationManager.getProviders(true);
getProvides()方法接受一個布爾型參數,傳入true就表示隻有啟用的位置提供器才會被傳回,之後從providesList中判斷是否包含GPS定位的功能就好。
使用requestLocationUpdates()方法,隻要傳入LocationListener的執行個體,就可以裝置位置發生改變時擷取最新的位置資訊。
locationMabager.requestLocationUpdates(LocationManager.GPS_PROVIDER,5000,10,new LocationListener(){});
參數:1.位置提供器的類型2.監聽位置變化的時間間隔3.監聽位置變化的距離間隔4.LocationListener監聽器
反向地理編碼,看的懂得位置資訊
使用Geocoding API進行反向地理編碼首先發送一個HTTP請求給谷歌伺服器,然後将傳回的JSON資料進行解析
public class MainActivity extends Activity {
public static final int SHOW_LOCATION = 0;
private TextView positionTextView;
private LocationManager locationManager;
private String provider;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
positionTextView = (TextView) findViewById(R.id.position_text_view);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// 擷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 {
// 沒有可用提示使用者
Toast.makeText(this, "No location provider to use",
Toast.LENGTH_SHORT).show();
return;
}
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
// 顯示目前裝置的位置資訊
showLocation(location);
}
locationManager.requestLocationUpdates(provider, 5000, 1,
locationListener);
}
protected void onDestroy() {
super.onDestroy();
if (locationManager != null) {
// 關閉程式時将監聽器移除
locationManager.removeUpdates(locationListener);
}
}
LocationListener locationListener = new LocationListener() {
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onLocationChanged(Location location) {
// 更新目前裝置資訊
showLocation(location);
}
};
private void showLocation(final Location location) {
new Thread(new Runnable() {
@Override
public void run() {
try {
// 組裝反向地理編碼的接口
StringBuilder url = new StringBuilder();
url.append("http://maps.googleapis.com/maps/api/geocode/json?latlng=");
url.append(location.getLatitude()).append(",")
.append(location.getLongitude());
url.append("&sensor=false");
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url.toString());
// 在請求消息中指定語言,保證伺服器傳回中文資料
httpGet.addHeader("Accept-Language", "zh-CN");
HttpResponse httpResponse = httpClient.execute(httpGet);
if (httpResponse.getStatusLine().getStatusCode() == 200) {
HttpEntity entity = httpResponse.getEntity();
String response = EntityUtils.toString(entity, "utf-8");
JSONObject jsonObject = new JSONObject(response);
// 擷取results節點下的位置資訊
JSONArray resultArray = jsonObject.getJSONArray("results");
if (resultArray.length() > 0) {
JSONObject subObject = resultArray.getJSONObject(0);
// 取出格式化的位置資訊
String address = subObject.getString("formatted_address");
Message message = new Message();
message.what = SHOW_LOCATION;
message.obj = address;
handler.sendMessage(message);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
private Handler handler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case SHOW_LOCATION:
String currentPosition = (String) msg.obj;
positionTextView.setText(currentPosition);
break;
default:
break;
}
}
};
}
使用百度地圖
首先在布局中方式一個百度提供的MapView自定義組建,是以使用它的時候需要帶上完整的包名。
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<com.baidu.mapapi.map.MapView
android:id="@+id/map_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true" />
</LinearLayout>
還需要設定多個權限
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_GPS" />
最終要的需要白申請的APIKey配置進去,也可以在代碼中動态配置
manager = new BMapManager(this);
manager.init("SHVPoTtIpzfonPD3HCkc5sIt", null);
public class MainActivity extends Activity {
private BMapManager manager;
private MapView mapView;
private LocationManager locationManager;
private String provider;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
manager = new BMapManager(this);
// API Key闇�瑕佹浛鎹㈡垚浣犺嚜宸辯殑
manager.init("SHVPoTtIpzfonPD3HCkc5sIt", null);
setContentView(R.layout.activity_main);
mapView = (MapView) findViewById(R.id.map_view);
mapView.setBuiltInZoomControls(true);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// 擷取位置提供其
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 {
Toast.makeText(this, "No location provider to use",
Toast.LENGTH_SHORT).show();
return;
}
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
navigateTo(location);
}
}
private void navigateTo(Location location) {
MapController controller = mapView.getController();
// 璁劇疆缂╂斁绾у埆
controller.setZoom(16);
GeoPoint point = new GeoPoint((int) (location.getLatitude() * 1E6),
(int) (location.getLongitude() * 1E6));
// 璁劇疆鍦闆浘涓績鐐�
controller.setCenter(point);
MyLocationOverlay myLocationOverlay = new MyLocationOverlay(mapView);
LocationData locationData = new LocationData();
// 鎸囧畾鎴戠殑浣嶇疆
locationData.latitude = location.getLatitude();
locationData.longitude = location.getLongitude();
myLocationOverlay.setData(locationData);
mapView.getOverlays().add(myLocationOverlay);
// 鍒鋒柊浣挎柊澧炶鐩栫墿鐢熸晥
mapView.refresh();
PopupOverlay pop = new PopupOverlay(mapView, new PopupClickListener() {
@Override
public void onClickedPopup(int index) {
// 鐩稿簲鍥劇墖鐨勭偣鍑諱簨浠�
Toast.makeText(MainActivity.this,
"You clicked button " + index, Toast.LENGTH_SHORT)
.show();
}
});
// 鍒涘緩涓�涓暱搴︿負3鐨凚itmap鏁扮粍
Bitmap[] bitmaps = new Bitmap[3];
try {
// 灏嗕笁寮犲浘鐗囪鍙栧埌鍐呭瓨涓�
bitmaps[0] = BitmapFactory.decodeResource(getResources(),
R.drawable.left);
bitmaps[1] = BitmapFactory.decodeResource(getResources(),
R.drawable.middle);
bitmaps[2] = BitmapFactory.decodeResource(getResources(),
R.drawable.right);
} catch (Exception e) {
e.printStackTrace();
}
pop.showPopup(bitmaps, point, 18);
}
@Override
protected void onDestroy() {
mapView.destroy();
if (manager != null) {
manager.destroy();
manager = null;
}
super.onDestroy();
}
@Override
protected void onPause() {
mapView.onPause();
if (manager != null) {
manager.stop();
}
super.onPause();
}
@Override
protected void onResume() {
mapView.onResume();
if (manager != null) {
manager.start();
}
super.onResume();
}
}