android - 调用 WifiManager startScan 时抛出 SecurityException

Question

我正在使用 AlarmManager 启动的 PendingIntent(使用 setRepeating)开始 wifi 扫描(使用 IntentService) 每隔几分钟。在大多数设备和大多数情况下，这没有问题。但是，在多个设备上我收到以下错误(无法在任何测试设备上重现该错误。这是来自用户设备的崩溃日志):

java.lang.RuntimeException: Unable to start service com.myapp.android.service.MyService@44a9701 with Intent { act=com.myapp.android.ACTION_PERFORM_WIFI_SCAN flg=0x4 cmp=com.myapp/com.mayapp.android.service.MyService (has extras) }: java.lang.SecurityException: Permission Denial: broadcast from android asks to run as user -1 but is calling from user 0; this requires android.permission.INTERACT_ACROSS_USERS_FULL or android.permission.INTERACT_ACROSS_USERS
       at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3021)
       at android.app.ActivityThread.-wrap17(ActivityThread.java)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1443)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:148)
       at android.app.ActivityThread.main(ActivityThread.java:5415)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:725)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:615)
Caused by: java.lang.SecurityException: Permission Denial: broadcast from android asks to run as user -1 but is calling from user 0; this requires android.permission.INTERACT_ACROSS_USERS_FULL or android.permission.INTERACT_ACROSS_USERS
       at android.os.Parcel.readException(Parcel.java:1599)
       at android.os.Parcel.readException(Parcel.java:1552)
       at android.net.wifi.IWifiManager$Stub$Proxy.startScan(IWifiManager.java:1045)
       at android.net.wifi.WifiManager.startScan(WifiManager.java:1088)
       ...

我正在从我的应用程序创建 PendingIntent，所以我看不出 WifiManager 抛出 SecurityException 的原因(特别是因为这种情况很少发生).

PendingIntent代码启动的IntentService如下:

mContext.registerReceiver(mWifiScanReceiver, new IntentFilter(
                    WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));

boolean ok = mWifiManager.startScan();

关于可能导致此问题的任何想法？

Answer 1

发生这种情况是因为 android m 的新应用权限。请参阅 wifimanager 的 getScanResults() for api 23 源代码上方的注释-

/**
     * Return the results of the latest access point scan.
     * @return the list of access points found in the most recent scan. An app must hold
     * {@link android.Manifest.permission#ACCESS_COARSE_LOCATION ACCESS_COARSE_LOCATION} or
     * {@link android.Manifest.permission#ACCESS_FINE_LOCATION ACCESS_FINE_LOCATION} permission
     * in order to get valid results.
     */
public List<ScanResult> getScanResults() {
        try {
            return mService.getScanResults(mContext.getOpPackageName());
        } catch (RemoteException e) {
            return null;
        }
    }

因此，您必须向用户询问运行时权限。将这些权限放在您的 list 中-

  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
  <uses-permission android:name="android.permission.INTERNET"/>
  <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

从 api 23 开始，您需要获得访问用户位置的权限才能使用它。我建议您使用基于 api 级别的权限检查，并仅在授予权限后才启动 Intent 。像这样的——

if (Build.VERSION.SDK_INT >= 23) {
int hasReadLocationPermission = checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION);
      if (hasReadLocationPermission != PackageManager.PERMISSION_GRANTED) {
        if (!ActivityCompat.shouldShowRequestPermissionRationale(HomeActivity.this, Manifest.permission.ACCESS_FINE_LOCATION)) {
          showMessageOKCancel("You need to allow access to GPS",
              new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                  ActivityCompat.requestPermissions(HomeActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, GPS_ENABLE_REQUEST);
                }
              });
          return;
        }
        ActivityCompat.requestPermissions(HomeActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, GPS_ENABLE_REQUEST);
        return;
      }
      if (locationManager != null && !locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
        gotoGPSEnableScreen();
      } else {
        //Permissions granted and gps is on
        launchService(true);
      }
}

进一步检查结果-

@Override
  public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    switch (requestCode) {
      case GPS_ENABLE_REQUEST:
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
          if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
            gotoGPSEnableScreen();
          }
        } else {
          launchService(false);
        }
      default:
        return;
    }
  }

更新:

android.permission.INTERACT_ACROSS_USERS_FULL 是签名级权限。只需在您的 list 中添加此 android:protectionLevel="signature"即可。

更多细节你可以检查这个

http://developer.android.com/guide/topics/manifest/permission-element.html

<permission android:name="android.permission.INTERACT_ACROSS_USERS_FULL" android:protectionLevel="signature"/>