使用Android版Google Maps API实时动态跟踪路线 [英] Dynamically tracing a route in real time using Google Maps API for Android
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问题描述
我对Android开发非常陌生，我正在尝试创建一个应用程序，该应用程序将在行走时使用地图叠加层来跟踪路线.我已经能够启动并运行该地图，并且可以显示它的运动，但是我对如何显示在地图上所走的路线一无所知.我认为我需要使用折线来执行此操作，并且我尝试设置一个List，然后从该List绘制线，但是我不确定这是否是合适的逻辑.任何帮助将不胜感激.
I am very new to Android development, and I am trying to create an app which will trace a route using a map overlay as I walk. I have been able to get the map up and running, and can get it to show my movement, but I am lost as to how to show the route taken on the map. I figure I need to use a polyline to do so, and I have tried to set up a List, and then to draw the line from that List, but I'm not sure if this is the appropriate logic to use. Any help would definitely be appreciated.
这是我到目前为止的代码:
Here is the code I have so far:
ACTIVITY_MAIN_XML :
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.MapFragment"
/>
MAINACTIVITY.JAVA :
package com.example.google_maps_test;
import java.util.List;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient;
import com.google.android.gms.common.GooglePlayServicesClient.OnConnectionFailedListener;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.LocationSource.OnLocationChangedListener;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Polyline;
import com.google.android.gms.maps.model.PolylineOptions;
import android.location.Location;
import android.location.LocationListener;
import android.os.Build;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.widget.Toast;
public class MainActivity extends Activity implements GooglePlayServicesClient.ConnectionCallbacks,
OnConnectionFailedListener, LocationListener{
private OnLocationChangedListener mListener;
GoogleMap mMap;
LocationClient mLocationClient;
Location mCurrentLocation;
LocationRequest mLocationRequest;
List<LatLng>routePoints;
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mMap =((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();
mMap.setMyLocationEnabled(true);
mLocationClient = new LocationClient(this,this, this);
mLocationRequest = LocationRequest.create();
mLocationRequest.setInterval(1000);
mLocationRequest.setPriority(mLocationRequest.PRIORITY_HIGH_ACCURACY);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onConnected(Bundle dataBundle) {
Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
Location location = mLocationClient.getLastLocation();
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
routePoints.add(latLng);
CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 17);
mMap.animateCamera(cameraUpdate);
}
@Override
public void onDisconnected() {
Toast.makeText(this, "Disconnected. Please re-connect.",
Toast.LENGTH_SHORT).show();
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public void onStart(){
super.onStart();
mLocationClient.connect();
}
public void onStop(){
mLocationClient.disconnect();
super.onStop();
}
public void activate(OnLocationChangedListener listener){
mListener = listener;
}
public void deactivate(){
mListener = null;
}
@Override
public void onLocationChanged(Location location) {
if(mListener != null){
mListener.onLocationChanged(location);
}
LatLng mapPoint = new LatLng(location.getLatitude(), location.getLongitude());
routePoints.add(mapPoint);
Polyline route = mMap.addPolyline(new PolylineOptions());
route.setPoints(routePoints);
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
ANDROIDMANIFEST_XML :
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.google_maps_test"
android:versionCode="1"
android:versionName="1.0" >
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.google_maps_test.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="com.google.android.maps.v2.API_KEY"
android:value="AIzaSyCOqSOYCyR-0bji10qcHa1WByfGoW-2ZsU"/>
</application>
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
</manifest>
当我运行该应用程序时，由于OnLocationChanged方法中的Null Pointer异常而崩溃.
When I run this app, it crashes due to a Null Pointer Exception in the OnLocationChanged method.
在此先感谢您的帮助！
推荐答案
您可以尝试以下方法:它在尝试接收我的位置时修复了我的应用程序中的错误
You could try this : It fixed an error at my application when trying to receive my location
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
if (location != null)
{
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(location.getLatitude(), location.getLongitude()), 13));
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(new LatLng(location.getLatitude(), location.getLongitude())) // Sets the center of the map to location user
.zoom(17) // Sets the zoom
.bearing(90) // Sets the orientation of the camera to east
.tilt(40) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
map.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
}
这篇关于使用Android版Google Maps API实时动态跟踪路线的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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