Android 获取位置时的java.lang.NullPointerException

我有一些问题，我无法在模拟器中重新创建，但我在android市场上不断收到错误报告，我不知道如何解决。。。任何其他可能看到它的人都会很高兴

有时此报告

java.lang.NullPointerException
at android.webkit.WebViewDatabase.getCacheTotalSize(WebViewDatabase.java:734)
at android.webkit.CacheManager.trimCacheIfNeeded(CacheManager.java:548)
at android.webkit.WebViewWorker.handleMessage(WebViewWorker.java:190)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.os.HandlerThread.run(HandlerThread.java:60)

有时也会出现此报告

java.lang.RuntimeException: Unable to start activity ComponentInfo{polis.koll/polis.koll.WebPageLoader}: java.lang.IllegalArgumentException: provider==null
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2737)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2753)
at android.app.ActivityThread.access$2500(ActivityThread.java:129)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2107)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:143)
at android.app.ActivityThread.main(ActivityThread.java:4701)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalArgumentException: provider==null
at android.location.LocationManager.requestLocationUpdates(LocationManager.java:625)
at polis.koll.WebPageLoader.getLocation(WebPageLoader.java:54)
at polis.koll.WebPageLoader.onCreate(WebPageLoader.java:70)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2701)

这是我的代码

    public class WebPageLoader extends Activity implements LocationListener{
    public static String Android_ID = null;
    final Activity activity = this;
    private Location mostRecentLocation;

    private void CheckEnableGPS(){
        String provider = Settings.Secure.getString(getContentResolver(),
          Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
           if(!provider.equals("")){
               //GPS Enabled
               getLocation();
           }else{
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
               startActivity(intent);
           }

       }


private void getLocation() {
    String provider = Settings.Secure.getString(getContentResolver(),
          Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
           if(!provider.equals("")){
    LocationManager locationManager =
      (LocationManager)getSystemService(Context.LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    criteria.setAccuracy(Criteria.ACCURACY_FINE);
    String bestprovider = locationManager.getBestProvider(criteria,true);
    locationManager.requestLocationUpdates(bestprovider, 1, 500, this);     
    mostRecentLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
         }else{
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
               startActivity(intent);
           }
  }

@Override
public void onCreate(Bundle savedInstanceState)
{
    //AdManager.setTestDevices( new String[] { AdManager.TEST_EMULATOR } );
    super.onCreate(savedInstanceState);
    this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
    setContentView(R.layout.main);

    getLocation();
    Android_ID = Secure.getString(getContentResolver(), Secure.ANDROID_ID);


    WebView webView = (WebView) findViewById(R.id.webView);
    webView.getSettings().setJavaScriptEnabled(true);
    /** Allows JavaScript calls to access application resources **/
    webView.addJavascriptInterface(new JavaScriptInterface(), "android16");
    webView.setWebChromeClient(new WebChromeClient() {
        public void onProgressChanged(WebView view, int progress)
        {
            activity.setTitle("Letar poliskontroller");
            activity.setProgress(progress * 100);


            if(progress == 100)
                activity.setTitle(R.string.app_name);
        }
    });


    webView.setWebViewClient(new WebViewClient() {

        @Override
        public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
        {
            // Handle the error
        }


     // Testade att ta bort denna override för att få market länkar att fungera
     //   @Override
     //   public boolean shouldOverrideUrlLoading(WebView view, String url)
     //   {
     //       view.loadUrl(url);
     //       return true;
     //   }
    });

    if (Locale.getDefault().getLanguage().equals("sv")){
    //webView.loadUrl("file:///android_asset/android.html");
        webView.loadUrl("file:///android_asset/findgps_sv.html");
    }else{
    //webView.loadUrl("http://m.bryggplatsen.se/android/polis/index.php");
    //webView.loadUrl("file:///android_asset/android_en.html");
        webView.loadUrl("file:///android_asset/findgps_en.html");
    }



}
    /** Sets up the interface for getting access to Latitude and Longitude data from device
     **/




private class JavaScriptInterface {
    public double getLatitude(){
        return mostRecentLocation != null ? mostRecentLocation.getLatitude() : Double.NaN;
    }

    public double getLongitude(){
        return mostRecentLocation != null ? mostRecentLocation.getLongitude() : Double.NaN;
    }


    public String getAndroid_ID(){
        return Android_ID;
    }

     public void sharethisapp(){
     startActivity(Intent.createChooser(sharespotIntent(), "Share this warning"));
     }
  }


@Override
public void onLocationChanged(Location location) {
    // TODO Auto-generated method stub

    getLocation();
    //CheckEnableGPS();
}

@Override
public void onProviderDisabled(String provider) {
    // TODO Auto-generated method stub
    getLocation();
}

@Override
public void onProviderEnabled(String provider) {
    // TODO Auto-generated method stub
    getLocation();
}

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


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu);
    MenuItem item = menu.add("Shut down");
    item.setIcon(R.drawable.exit);

    item = menu.add("Share");
    item.setIcon(R.drawable.m_share);

    item = menu.add("Fix GPS");
    item.setIcon(R.drawable.globe);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getTitle() == "Shut down") {
        System.exit(0);
        finish();
    }
    if (item.getTitle() == "Fix GPS") {
        getLocation();
    }
    if (item.getTitle() == "Share") {
        if (Locale.getDefault().getLanguage().equals("sv")){
        startActivity(Intent.createChooser(shareIntent(), "Dela denna app"));
        }else{
        startActivity(Intent.createChooser(shareIntent(), "Share this app"));
        }
    }
    return true;
}

private Intent shareIntent() {
        Intent shareIntent = new Intent(android.content.Intent.ACTION_SEND);
        shareIntent.setType("text/plain");      
    if (Locale.getDefault().getLanguage().equals("sv")){
        shareIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Testa denna android app...");
        return shareIntent.putExtra(android.content.Intent.EXTRA_TEXT, "index.php");
    }else{
        shareIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Try this cool android app...");
        return shareIntent.putExtra(android.content.Intent.EXTRA_TEXT, "index_en.php");         
    }

}


private Intent sharespotIntent() {
    Intent sharespotIntent = new Intent(android.content.Intent.ACTION_SEND);
    sharespotIntent.setType("text/plain");      
if (Locale.getDefault().getLanguage().equals("sv")){
    sharespotIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, " la just upp en ny varning i appen Polisradar");
    return sharespotIntent.putExtra(android.content.Intent.EXTRA_TEXT, "warn.php?lat=" + mostRecentLocation.getLatitude() + "&lng=" + mostRecentLocation.getLongitude() + "");
}else{
    sharespotIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, " just added a new warning in the app Policeradar");
    return sharespotIntent.putExtra(android.content.Intent.EXTRA_TEXT, "warn_en.php?lat=" + mostRecentLocation.getLatitude() + "&lng=" + mostRecentLocation.getLongitude() + "");       
    }
}

---

}

如果请求的名称不在数据库中，则方法Settings.Secure.getString（）可以返回null。但我不知道为什么找不到Settings.Secure.LOCATION\u PROVIDERS\u ALLOWED。但是，在检查提供程序是否为空字符串之前，代码不会（在getLocation（）中）检查该提供程序是否为null。我认为这是你第二次例外的原因

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试图在不支持代码中某些内容的操作系统版本上运行应用程序，也可能会导致框架中看似随机的错误。确保您的代码是根据清单中设置的minSdkVersion编译的，而不仅仅是targetSdkVersion。

请注意这个问题。我不知道这是否是您的问题，但我正在考虑在应用程序之间共享一些文件，并尝试修改我的AndroidManifest.xml文件中的属性。一旦我这样做了，我得到了与您报告的完全相同的错误，我的应用程序无法正常启动（似乎是由于AdRequest失败）。即使在从清单中删除sharedUserId属性之后，我仍然会收到错误，尽管我认为它来自首选项数据库

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底线是部署应用程序后不要更改其sharedUserId属性，否则您将需要一个卸载/重新安装周期才能使所有内容重新正常工作。

这似乎不是您的错。在例外情况的来源方面是否存在任何模式：某些设备、某些制造商、某些安卓版本等？不，我看不出报告中有哪些手机或安卓。在我自己使用android 2.2的手机（HTC Desire）上，我有时注意到应用程序有时会停止，但不是经常停止或崩溃，只是没有进入下一步。好的，我会尝试使其返回null，以便提供商不会返回null，我会报告它是如何运行的goes@Ted霍普-你认为这能奏效吗？如果（provider==null）provider=“”；请尝试“if（！（provider==null | | provider.equals（“”））{…}”。不，仍然会得到以下错误：由以下原因引起：java.lang.IllegalArgumentException:provider==nullim猜测其此行：String provider=Settings.Secure.getString（getContentResolver（），Settings.Secure.LOCATION\u PROVIDERS\u允许）；