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android - 位置应用程序不断崩溃

转载 作者：行者123 更新时间：2023-12-03 17:22:10 29 4
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编辑
我已经对我的类(class)进行了一些更改，但我仍然遇到同样的问题。我无法弄清楚当我启动应用程序时它会崩溃。我在某处读到，如果它不存在，它可能无法找到以前的位置？也许有更好的方法来获取用户位置的纬度和经度，因为我想要的只是 gps 坐标。

显现:

<?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，我试图将其放在一起以获取用户当前的 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，但这是我的主要类(class): 
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();
}


}

这个类是获取并保存经纬度: 
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;
}
}

这个类是为了显示结果: 
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;
    }
}
}

日志猫 
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)

最佳答案

转到您的手机设置并允许 GPS 和 WiFi 位置。这种方法...

provider = locManager.getBestProvider(criteria, false);

...不关心您是否打开了 GPS。大多数情况下会尝试从 GPS 而不是 WiFi 获取位置。

此外，如果您添加了以下行，请检查您的 list : 
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

这将确保您的应用程序可以访问 Internet 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: 
locManager.requestLocationUpdates(provider, 0L, 0.0F, this);

这实际上会要求位置管理器开始请求您的位置。

关于android - 位置应用程序不断崩溃，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30578394/

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