谷歌地圖API代碼未顯示當前位置

Question

我想在用戶打開活動後立即顯示用戶的當前位置。

這是我編碼到目前爲止。

package com.android.carmanager; 

import android.content.Context; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 
import android.os.Bundle; 
import android.widget.Toast; 
import com.google.android.maps.GeoPoint; 
import com.google.android.maps.MapActivity; 
import com.google.android.maps.MapController; 
import com.google.android.maps.MapView; 

public class CarFinder extends MapActivity{ 
private MapView mapView; 
private MapController mapController; 
private LocationManager locationManager; 
private LocationListener locationListener; 

@Override 
    public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.carfinder); 
    mapView = (MapView) findViewById(R.id.mapView); 
     mapView.setStreetView(true); 
     mapView.setBuiltInZoomControls(true); 
     mapView.displayZoomControls(true); 

     mapController = mapView.getController(); 
     mapController.setZoom(16); 

     locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 

     locationListener = new GPSLocationListener(); 

     locationManager.requestLocationUpdates(
       LocationManager.GPS_PROVIDER, 
       0, 
       0, 
       locationListener); 
    } 
private class GPSLocationListener implements LocationListener 
{ 
    public void onLocationChanged(Location location) { 
    if (location != null) { 
     GeoPoint point = new GeoPoint(
      (int) (location.getLatitude() * 1E6), 
      (int) (location.getLongitude() * 1E6)); 

     Toast.makeText(getBaseContext(), 
      "Latitude: " + location.getLatitude() + 
      " Longitude: " + location.getLongitude(), 
      Toast.LENGTH_SHORT).show(); 

     mapController.animateTo(point); 
     mapController.setZoom(16); 
     mapView.invalidate(); 
    } 
    } 

public void onProviderDisabled(String arg0) { 
    // TODO Auto-generated method stub 

} 

public void onProviderEnabled(String provider) { 
    // TODO Auto-generated method stub 

} 

public void onStatusChanged(String provider, int status, Bundle extras) { 
    // TODO Auto-generated method stub 

} 
} 

@Override 
    protected boolean isRouteDisplayed(){ 
     //TODO Auto-generated method stub 
     return false; 

    } 
    } 

這裏附加清單文件，以及：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="com.android.carmanager" 
android:versionCode="1" 
android:versionName="1.0" > 

    <uses-sdk android:minSdkVersion="15" /> 
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" ></uses-permission> 
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" ></uses-permission> 
<uses-permission android:name="android.permission.INTERNET" ></uses-permission> 

<application 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name"> 
     <uses-library android:name = "com.google.android.maps" /> 

    <activity android:name=".CarManagerActivity" android:label= "@string/app_name"> 
    <intent-filter> 
<action android:name="android.intent.action.MAIN" /> 
<category android:name="android.intent.category.LAUNCHER" /> 
</intent-filter> 
</activity> 
    <activity android:name=".MileageCalculator" android:label= "@string/app_name"></activity> 
    <activity android:name=".About" android:label= "@string/app_name"></activity> 
<activity android:name=".CarFinder" android:label="@string/app_name"></activity> 
</application> 

</manifest> 

這是錯誤日誌文件的貓如果需要的話。就位置而言，我找不到任何錯誤。

05-27 16:07:05.647: I/dalvikvm(706): threadid=3: reacting to signal 3 
05-27 16:07:05.697: I/dalvikvm(706): Wrote stack traces to '/data/anr/traces.txt' 
05-27 16:07:06.156: D/gralloc_goldfish(706): Emulator without GPU emulation detected. 
05-27 16:07:06.167: I/dalvikvm(706): threadid=3: reacting to signal 3 
05-27 16:07:06.197: I/dalvikvm(706): Wrote stack traces to '/data/anr/traces.txt' 
05-27 16:07:25.666: I/dalvikvm(706): threadid=3: reacting to signal 3 
05-27 16:07:25.808: I/dalvikvm(706): Wrote stack traces to '/data/anr/traces.txt' 
05-27 16:07:25.868: D/dalvikvm(706): GC_CONCURRENT freed 161K, 3% free 9352K/9607K, paused 12ms+7ms 
05-27 16:07:25.868: W/CursorWrapperInner(706): Cursor finalized without prior close() 
05-27 16:07:25.868: W/CursorWrapperInner(706): Cursor finalized without prior close() 
05-27 16:07:26.186: I/dalvikvm(706): threadid=3: reacting to signal 3 
05-27 16:07:26.326: I/dalvikvm(706): Wrote stack traces to '/data/anr/traces.txt' 
05-27 16:07:26.396: D/dalvikvm(706): GC_CONCURRENT freed 40K, 3% free 9764K/9991K, paused 12ms+21ms 
05-27 16:07:26.436: I/Maps.MyLocationOverlay(706): Request updates from gps 
05-27 16:07:26.656: E/ZoomButtonsController(706): Cannot make the zoom controller visible if the owner view is not attached to a window. 
05-27 16:07:26.746: I/dalvikvm(706): threadid=3: reacting to signal 3 
05-27 16:07:26.767: I/dalvikvm(706): Wrote stack traces to '/data/anr/traces.txt' 
05-27 16:07:26.827: I/MapActivity(706): Handling network change notification:CONNECTED 
05-27 16:07:26.827: E/MapActivity(706): Couldn't get connection factory client 
05-27 16:07:27.137: D/dalvikvm(706): GC_CONCURRENT freed 40K, 3% free 10167K/10375K, paused 8ms+6ms 
05-27 16:07:27.188: I/dalvikvm(706): threadid=3: reacting to signal 3 
05-27 16:07:27.227: I/dalvikvm(706): Wrote stack traces to '/data/anr/traces.txt' 
05-27 16:07:27.887: D/dalvikvm(706): GC_CONCURRENT freed 375K, 5% free 10237K/10759K, paused 12ms+6ms 

但是，當我打開活動，地圖打開，位置無處可見。

它甚至不顯示經度/緯度。

如何調整我的代碼以顯示當前位置？

Answer 1

點1：按照@Shabbir在上述意見，建議是使用MyLocationOverlay。

---

點2：

但是當我打開活動，地圖打開了，地點是無處可看。

MyLocationOverlay需要時間來獲得位置修復，所以它開始時不顯示任何內容。它只顯示找到第一個修復程序後的位置。

如果您在啓動此活動之前已經知道您的位置，可以繼承MyLocationOverlay以接受構造函數中的參數defaultLocation。然後重寫draw()方法是這樣的：

public synchronized boolean draw(Canvas canvas, MapView mapView, 
    boolean shadow, long when) 
{ 
    //if no location found 
    if(getLastFix()==null && defaultLocation!=null) 
    { 
     drawMyLocation(canvas, mapView, defaultLocation, DataUtilities.locationToGeoPoint(defaultLocation), when); 
    } 

    return super.draw(canvas, mapView, shadow, when); 
} 

畫出你的默認的位置，如果沒有鎖定尚未被發現，否則只是讓基類做它的事。

使用此方法，您可以直接顯示初始位置（defaultLocation），同時等待您的設備獲得更好的修復。

Answer 2

看一看這個... http://android-er.blogspot.in/2009/11/mapview-to-center-on-current-location.html

Answer 3

使用此片段

List<Overlay> over_lay = mapView.getOverlays(); 
    MyLocationOverlay mylocationoverlay = new MyLocationOverlay(this, mapView); 
    over_lay.add(mylocationoverlay);