修改 我已经对课程做了一些修改，但我仍然遇到同样的问题。当我启动应用程序时，我无法弄清楚它会崩溃。我读到某个地方，如果它不存在，它可能找不到以前的位置？也许有一种更好的方法让我获得用户位置的纬度和经度，因为我想要的只是gps坐标。
清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="viaan.carl.doordingdefender" >
<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_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
我有一个应用程序我试图拼凑起来抓住用户当前的gps位置，并使用这些坐标通过JSON获取数据以向用户报告。我最初让应用程序工作以显示gps坐标，但现在我无法正常打开它。我不确定在哪里看，但这是我的主类：
public class MainActivity extends ActionBarActivity implements LocationListener{
private TextView latitudeField;
private TextView longitudeField;
private LocationManager locManager;
private String provider;
myGPS gps = new myGPS(this);
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new ServiceHandler()).commit();
}
latitudeField = (TextView)findViewById(R.id.TextView02);
longitudeField = (TextView)findViewById(R.id.TextView04);
//Get the location manager
locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
//Define the criteria how to select the location provider -> use default
Criteria criteria = new Criteria();
provider = locManager.getBestProvider(criteria, false);
Location location = locManager.getLastKnownLocation(provider);
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
onLocationChanged(location);
} else {
latitudeField.setText("Location not available");
longitudeField.setText("Location not available");
}
}
@Override
public void onLocationChanged(Location location) {
int lat = (int) location.getLatitude();
int lng = (int) location.getLongitude();
gps.setLat(lat);
gps.setLng(lng);
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
Toast.makeText(this, "Enabled new provider " + provider, Toast.LENGTH_SHORT).show();
}
@Override
public void onProviderDisabled(String provider) {
Toast.makeText(this, "Disabled provider" + provider, Toast.LENGTH_SHORT).show();
}
}
这个课程是为了获得并保持纬度和经度：
public class myGPS {
private int lat;
private int lng;
SharedPreferences prefs;
public myGPS(Activity activity) {
prefs = activity.getPreferences(Activity.MODE_PRIVATE);
}
void setLng(int lng) {
this.lng = lng;
}
int getLat() {
return lat;
}
int getLng() {
return lng;
}
void setLat(int lat) {
this.lat = lat;
}
}
此类用于显示结果：
public class ServiceHandler extends Fragment {
Handler handler;
TextView detailsField;
myGPS gps = new myGPS(getActivity());
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_wind, container, false);
detailsField = (TextView) rootView.findViewById(R.id.details_field);
return rootView;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
windData(gps.getLat(), gps.getLng());
}
private static final String OPEN_WEATHER_MAP_API =
"api.openweathermap.org/data/2.5/weather?lat=%d&lon=%d&imperial";
private void windData(final Integer lat, final Integer lng) {
new Thread() {
public void run() {
final JSONObject json = windFetch.getJSON(getActivity(), lat, lng);
if (json == null) {
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(getActivity(),
getActivity().getString(R.string.place_not_found),
Toast.LENGTH_LONG).show();
}
});
} else {
handler.post(new Runnable() {
@Override
public void run() {
renderWeather(json);
}
});
}
}
}.start();
}
private void renderWeather(JSONObject json) {
try {
JSONObject wind = json.getJSONObject("wind");
int Deg = (int) Math.round((wind.getDouble("deg") - 11.25) / 22.5);
String windDir = null;
switch (Deg) {
case 0:
windDir = "N";
break;
case 1:
windDir = "NNE";
break;
case 2:
windDir = "NE";
break;
case 3:
windDir = "ENE";
break;
case 4:
windDir = "E";
break;
case 5:
windDir = "ESE";
break;
case 6:
windDir = "SE";
break;
case 7:
windDir = "SSE";
break;
case 8:
windDir = "S";
break;
case 9:
windDir = "SSW";
break;
case 10:
windDir = "SW";
break;
case 11:
windDir = "WSW";
break;
case 12:
windDir = "W";
break;
case 13:
windDir = "WNW";
break;
case 14:
windDir = "NW";
break;
case 15:
windDir = "NNW";
break;
}
detailsField.setText(
wind.getString("Wind Speed: " + wind.getString("speed") + "mi/hr " +
windDir));
} catch (Exception e) {
Log.e("SimpleWeather", "One or more fields not found in the JSON data");
}
}
public static JSONObject getJSON(Context context, Integer lat, Integer lng) {
try {
URL url = new URL(String.format(OPEN_WEATHER_MAP_API, lat, lng));
HttpURLConnection connection =
(HttpURLConnection) url.openConnection();
connection.addRequestProperty("x-api-key",
context.getString(R.string.open_weather_maps_app_id));
BufferedReader reader = new BufferedReader(
new InputStreamReader(connection.getInputStream()));
StringBuffer json = new StringBuffer(1024);
String tmp = "";
while ((tmp = reader.readLine()) != null)
json.append(tmp).append("\n");
reader.close();
JSONObject data = new JSONObject(json.toString());
if (data.getInt("cod") != 200) {
return null;
}
return data;
} catch (Exception e) {
return null;
}
}
}
logcat的
06-05 09:05:56.427 25284-25284/? D/dalvikvm﹕ Late-enabling CheckJNI
06-05 09:05:56.439 25284-25284/? E/Trace﹕ error opening trace file: No such file or directory (2)
06-05 09:05:56.455 25284-25284/? I/dalvikvm﹕ Could not find method android.view.ViewGroup.onNestedScrollAccepted, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onNestedScrollAccepted
06-05 09:05:56.455 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 12215: Landroid/view/ViewGroup;.onNestedScrollAccepted (Landroid/view/View;Landroid/view/View;I)V
06-05 09:05:56.455 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
06-05 09:05:56.455 25284-25284/? I/dalvikvm﹕ Could not find method android.view.ViewGroup.onStopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.onStopNestedScroll
06-05 09:05:56.455 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 12221: Landroid/view/ViewGroup;.onStopNestedScroll (Landroid/view/View;)V
06-05 09:05:56.455 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0000
06-05 09:05:56.455 25284-25284/? I/dalvikvm﹕ Could not find method android.support.v7.internal.widget.ActionBarOverlayLayout.stopNestedScroll, referenced from method android.support.v7.internal.widget.ActionBarOverlayLayout.setHideOnContentScrollEnabled
06-05 09:05:56.455 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 9786: Landroid/support/v7/internal/widget/ActionBarOverlayLayout;.stopNestedScroll ()V
06-05 09:05:56.455 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x000e
06-05 09:05:56.459 25284-25284/? I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.internal.widget.TintTypedArray.getChangingConfigurations
06-05 09:05:56.459 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 393: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
06-05 09:05:56.459 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
06-05 09:05:56.459 25284-25284/? I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.internal.widget.TintTypedArray.getType
06-05 09:05:56.459 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 415: Landroid/content/res/TypedArray;.getType (I)I
06-05 09:05:56.459 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
06-05 09:05:56.459 25284-25284/? I/dalvikvm﹕ Could not find method android.content.res.Resources.getDrawable, referenced from method android.support.v7.internal.widget.ResourcesWrapper.getDrawable
06-05 09:05:56.459 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 356: Landroid/content/res/Resources;.getDrawable (ILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
06-05 09:05:56.459 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
06-05 09:05:56.459 25284-25284/? I/dalvikvm﹕ Could not find method android.content.res.Resources.getDrawableForDensity, referenced from method android.support.v7.internal.widget.ResourcesWrapper.getDrawableForDensity
06-05 09:05:56.459 25284-25284/? W/dalvikvm﹕ VFY: unable to resolve virtual method 358: Landroid/content/res/Resources;.getDrawableForDensity (IILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
06-05 09:05:56.459 25284-25284/? D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
06-05 09:05:56.475 25284-25284/? D/AndroidRuntime﹕ Shutting down VM
06-05 09:05:56.475 25284-25284/? W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xa619f908)
06-05 09:05:56.475 25284-25284/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{viaan.carl.doordingdefender/viaan.carl.doordingdefender.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at viaan.carl.doordingdefender.myGPS.<init>(myGPS.java:18)
at viaan.carl.doordingdefender.ServiceHandler.<init>(ServiceHandler.java:35)
at viaan.carl.doordingdefender.MainActivity.onCreate(MainActivity.java:30)
at android.app.Activity.performCreate(Activity.java:5104)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
转到手机设置并允许GPS和WiFi位置。这种方法......
cd /var/www
phpunit
...无论您是否打开GPS，都不在乎。大多数情况下会尝试从GPS而不是WiFi获取位置。
另外，如果您添加了以下行，请检查您的清单：
phpunit tests/ExampleTest.php
这将确保您的应用可以访问互联网以上传和下载JSON并检查位置服务。
稍后在onCreate方法内的代码中添加以下行：
provider = locManager.getBestProvider(criteria, false);
这实际上会要求位置经理开始请求您的位置。