本文主要是介绍更踪设备的地理位置(LocationManager),希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
地理位置与LocationManager
Android系统中的地理位置数据是由LocationManager系统服务提供的。该系统服务向所有需要地理数据的应用提供数据更新。更新数据的传送通常采用两种方式。
其中,使用LocationListener接口可能是最直接的一种方式。通过onLocationChanged(Location)方法,该接口提供的信息有:地理位置数据更新、状态更新以及定位服务提供者启动状态的通知消息。
如只需将地理位置数据发送给应用中的单个组件,使用LocationListener接口会很方便。提供LocationListener接口实现给LocationManager的requestLocationUpdates(…)或requestSingleUpdate(…)方法即可。
然而,若不管用户界面是否存在(如应用在后台运行),应用都需要持续定位用户地理位置。当然,我们也可以使用stickyService,但stickyService本身复杂难用,而且这种方式也不够轻量级。因此,我们使用自Android 2.3开始引入的PendingIntent。
使用PendingIntent获取地理位置信息更新,我们实际是要求LocationManager在将来某个时点帮忙发送某种类型的Intent。这样,即使应用组件。甚至是整个应用进程都销毁了,LocationManager仍会一直发送Intent,直到要求停止并按需启动新组件响应它们。利用这种优势,即使持续进行设备定位,也可以避免应用消耗过多的资源。
为管理与LocationManager的通讯,创建一个名为RunManager的单例类:
package com.huangfei.runtracker;import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;public class RunManager {public static final String TAG = "RunManager";public static final String ACTION_LOCATION = "com.huangfei.runtracker.ACTION_LOCATION";private static RunManager sRunManager;private Context mAppContext;private LocationManager mLocationManager;private RunManager(Context appContext) {mAppContext = appContext;mLocationManager = (LocationManager) mAppContext.getSystemService(Context.LOCATION_SERVICE);}public static RunManager get(Context context) {if (sRunManager == null) {sRunManager = new RunManager(context.getApplicationContext());}return sRunManager;}private PendingIntent getLocationPeindingIntent(boolean shouldcCreate) {Intent broadcast = new Intent(ACTION_LOCATION);int flags = shouldcCreate ? 0 : PendingIntent.FLAG_NO_CREATE;//flags参数告诉 PendingIntent.getBroadcast方法是否应该在系统中创建新的PendingIntentreturn PendingIntent.getBroadcast(mAppContext, 0, broadcast, flags);}/*** 启动地理位置更新*/public void startLocationupdates() {// 要求LocationManager通过GPS定位装置提供实时的定位数据更新String provider = LocationManager.GPS_PROVIDER;/*** 利用LocationManager的最近一次地理位置(使用于各种定位方式,如GPS、WIFE网络、手机基站等),* 来消除免用户开启定位时的长时间等待。* * 也可向LocationManager请求来自不同定位服务提供者的最近一次地理位置信息,或使用getAllProviders()方法* 获知协同工作的定位服务提供者。如遍历查看所有最近一次地理位置信息,应查看其准确性,并确定是否为比较新的时间戳。如较为久远,* 可不采用这些数据信息。*/Location lastKnownLocation = mLocationManager.getLastKnownLocation(provider);if(lastKnownLocation != null){lastKnownLocation.setTime(System.currentTimeMillis());broadcastLocation(lastKnownLocation);}PendingIntent pi = getLocationPeindingIntent(true);/*** requestLocationUpdates(String provider, long minTime, float minDistance, PendingIntent intent)* 四个参数中,最小等待时间(以毫秒为单位)以及最短移动距离(以米为单位)可用与决定发送下一次定位数据更新要移动的距离和要等待的时间*/mLocationManager.requestLocationUpdates(provider, 0, 0, pi);}/*** 发送最近一次地理位置信息的广播*/private void broadcastLocation(Location lastKnownLocation) {Intent intent = new Intent(ACTION_LOCATION);intent.putExtra(LocationManager.KEY_LOCATION_CHANGED, lastKnownLocation);mAppContext.sendBroadcast(intent);}/*** 停止地理位置更新* */public void stopLocationUpdates() {PendingIntent pi = getLocationPeindingIntent(false);if (pi != null) {mLocationManager.removeUpdates(pi);pi.cancel();}}/*** 判断地理位置是否更新*/public boolean isTrackRun() {return getLocationPeindingIntent(false) != null;}
}
接收定位数据更新broadcast
package com.huangfei.runtracker;import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationManager;
import android.util.Log;public class LocationReceiver extends BroadcastReceiver {public static final String TAG = "LocationReceiver";@Overridepublic void onReceive(Context context, Intent intent) {/*** LocationManager打包了附加额外信息的intent* LocationManager.KEY_LOCATION_CHANGED键值可指定一个表示最新更新的Location实例*/Location location = (Location) intent.getParcelableExtra(LocationManager.KEY_LOCATION_CHANGED);if (location != null) {onLocationReceived(context, location);return;}if (intent.hasExtra(LocationManager.KEY_PROVIDER_ENABLED)) {boolean enabled = intent.getBooleanExtra(LocationManager.KEY_PROVIDER_ENABLED, false);onProviderEnabledChanged(enabled);}}protected void onProviderEnabledChanged(boolean enabled) {Log.d(TAG, "Provider " + (enabled ? "enabled" : "disabled"));}protected void onLocationReceived(Context context, Location location) {Log.d(TAG, this + " Got location from " + location.getProvider() + ": "+ location.getLatitude() + ", " + location.getLongitude());}
}
<!-- 添加定位的权限以及GPS硬件uses-feature节点的添加 --><uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /><uses-feature
android:name="android.hardware.location.gps"android:required="true" /><receiver
android:name="com.huangfei.runtracker.LocationReceiver"android:exported="false" ><intent-filter><action android:name="com.huangfei.runtracker.ACTION_LOCATION" /></intent-filter></receiver>
使用定位数据刷新UI显示
package com.huangfei.runtracker;import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.IntentFilter;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;public class RunFragment extends Fragment {private BroadcastReceiver mLocationReceiver = new LocationReceiver(){protected void onLocationReceived(Context context, Location location) {mLastLocation = location;if(isVisible())updateUI();}protected void onProviderEnabledChanged(boolean enabled) {//GPS服务提供者启动或停止时,消息提示int toastText = enabled ? R.string.gps_enabled : R.string.gps_disabled;Toast.makeText(getActivity(), toastText, Toast.LENGTH_LONG).show();}};private RunManager mRunManager;private Run mRun;private Location mLastLocation;private Button mStartButton, mStopButton;private TextView mStartedTextView, mLatitudeTextView, mLongitudeTextView,mAltitudeTextView, mDurationTextView;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setRetainInstance(true);mRunManager = RunManager.get(getActivity());}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {View view = inflater.inflate(R.layout.fragment_run, container, false);mStartedTextView = (TextView) view.findViewById(R.id.run_startedTextView);mLatitudeTextView = (TextView) view.findViewById(R.id.run_latitudeTextView);mLongitudeTextView = (TextView) view.findViewById(R.id.run_longitudeTextView);mAltitudeTextView = (TextView) view.findViewById(R.id.run_altitudeTextView);mDurationTextView = (TextView) view.findViewById(R.id.run_durationTextView);mStartButton = (Button) view.findViewById(R.id.run_startButton);mStartButton.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {mRunManager.startLocationupdates();mRun = new Run();updateUI();}});mStopButton = (Button) view.findViewById(R.id.run_stopButton);mStopButton.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {mRunManager.stopLocationUpdates();updateUI();}});return view;}@Overridepublic void onStart() {super.onStart();getActivity().registerReceiver(mLocationReceiver, new IntentFilter(RunManager.ACTION_LOCATION));}@Overridepublic void onStop() {super.onStop();getActivity().unregisterReceiver(mLocationReceiver);}private void updateUI(){boolean started = mRunManager.isTrackRun();if(mRun != null){mStartedTextView.setText(mRun.getSartDate().toString());}int durationSenconds = 0;if(mRun != null && mLastLocation != null){durationSenconds = mRun.getDurationSeconds(mLastLocation.getTime());mLatitudeTextView.setText(Double.toString(mLastLocation.getLatitude()));mLongitudeTextView.setText(Double.toString(mLastLocation.getLongitude()));mAltitudeTextView.setText(Double.toString(mLastLocation.getAltitude()));}mDurationTextView.setText(Run.formatDuration(durationSenconds));mStartButton.setEnabled(!started);mStopButton.setEnabled(started);}
}
代码地址
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