比较简单的数学题，求3的范围<= Abs[6 - x] <= 5. Not hard to solve by hand, and Mathematica nails it, with the answer 1 <= x <= 3 || 9 <= x <= 11. The
仅限 Unix 从线程导入线程 从信号导入信号、警报、sigwait、SIGALRM 类检查（线程）： def __init__(自身): 超级().__init__() 信号（SIGALRM，检查.hand...
我尝试从 Google 获取我的 GCM 注册 ID。 我的代码： 字符串SENDER_ID =“722*****53”; /** * 向 GCM 服务器异步注册应用程序。 * * 存储注册信息... 我尝试从 Google 获取我的 GCM 注册 ID。 我的代码： String SENDER_ID = "722******53"; /** * Registers the application with GCM servers asynchronously. * <p> * Stores the registration ID and the app versionCode in the application's * shared preferences. */ private void registerInBackground() { new AsyncTask<Void, Void, String>() { @Override protected String doInBackground(Void... params) { String msg = ""; try { if (gcm == null) { gcm = GoogleCloudMessaging.getInstance(context); } regid = gcm.register(SENDER_ID); msg = "Device registered, registration ID=" + regid; // You should send the registration ID to your server over // HTTP, so it // can use GCM/HTTP or CCS to send messages to your app. sendRegistrationIdToBackend(); // For this demo: we don't need to send it because the // device will send // upstream messages to a server that echo back the message // using the // 'from' address in the message. // Persist the regID - no need to register again. storeRegistrationId(context, regid); } catch (IOException ex) { msg = "Error :" + ex.getMessage(); // If there is an error, don't just keep trying to register. // Require the user to click a button again, or perform // exponential back-off. } return msg; } @Override protected void onPostExecute(String msg) { mDisplay.append(msg + "\n"); } }.execute(null, null, null); } 我收到错误： 03-01 19:15:36.261: E/AndroidRuntime(3467): FATAL EXCEPTION: AsyncTask #1 03-01 19:15:36.261: E/AndroidRuntime(3467): java.lang.RuntimeException: An error occured while executing doInBackground() 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.os.AsyncTask$3.done(AsyncTask.java:299) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.setException(FutureTask.java:219) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.run(FutureTask.java:239) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.lang.Thread.run(Thread.java:841) 03-01 19:15:36.261: E/AndroidRuntime(3467): Caused by: java.lang.SecurityException: Not allowed to start service Intent { act=com.google.android.c2dm.intent.REGISTER pkg=com.google.android.gms (has extras) } without permission com.google.android.c2dm.permission.RECEIVE 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.app.ContextImpl.startServiceAsUser(ContextImpl.java:1800) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.app.ContextImpl.startService(ContextImpl.java:1772) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.content.ContextWrapper.startService(ContextWrapper.java:480) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.google.android.gms.gcm.GoogleCloudMessaging.b(Unknown Source) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.google.android.gms.gcm.GoogleCloudMessaging.register(Unknown Source) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.example.gcm.DemoActivity$1.doInBackground(DemoActivity.java:177) 03-01 19:15:36.261: E/AndroidRuntime(3467): at com.example.gcm.DemoActivity$1.doInBackground(DemoActivity.java:1) 03-01 19:15:36.261: E/AndroidRuntime(3467): at android.os.AsyncTask$2.call(AsyncTask.java:287) 03-01 19:15:36.261: E/AndroidRuntime(3467): at java.util.concurrent.FutureTask.run(FutureTask.java:234) 03-01 19:15:36.261: E/AndroidRuntime(3467): ... 4 more 这是我的清单： <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.manyexampleapp" android:installLocation="preferExternal" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="11" android:targetSdkVersion="18" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <uses-permission android:name="android.permission.GET_ACCOUNTS" /> <uses-permission android:name="android.permission.WAKE_LOCK" /> <uses-permission android:name="com.example.manyexampleapp.c2dm.permission.RECEIVE" /> <uses-permission android:name="com.example.manyexampleapp.gcm.permission.C2D_MESSAGE" /> <permission android:name="com.example.manyexampleapp.gcm.permission.C2D_MESSAGE" android:protectionLevel="signature" /> <application android:name="com.zoomer.ifs.BaseApplication" android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" /> <activity android:name="com.zoomer.ifs.MainActivity" android:label="@string/app_name" android:configChanges="orientation|keyboardHidden|screenSize" android:launchMode="singleTop"> <!-- <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> --> </activity> <!-- PUSH --> <!-- WakefulBroadcastReceiver that will receive intents from GCM services and hand them to the custom IntentService. The com.google.android.c2dm.permission.SEND permission is necessary so only GCM services can send data messages for the app. --> <receiver android:name="com.example.gcm.GcmBroadcastReceiver" android:permission="com.google.android.c2dm.permission.SEND" > <intent-filter> <!-- Receives the actual messages. --> <action android:name="com.google.android.c2dm.intent.RECEIVE" /> <category android:name="com.example.manyexampleapp" /> </intent-filter> </receiver> <service android:name="com.example.gcm.GcmIntentService" /> <activity android:name="com.example.gcm.DemoActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <!-- DB --> <activity android:name="com.example.db.DbActivity" android:label="@string/app_name" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.http.RestGetActivity" android:label="@string/app_name" android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen" > </activity> <activity android:name="com.example.fb.FacebookLoginActivity" 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="com.example.http.SendFeedbackActivity" 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="com.zoomer.general.SearchNearbyOffersActivity" android:label="@string/app_name" > <intent-filter> </intent-filter> </activity> <activity android:name="com.facebook.LoginActivity" android:label="@string/app_name" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.manyexampleapp.StoresListActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.fb.ShareActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.notifications.NotificationsActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.example.fb2.no_use.MainActivity" > <intent-filter> </intent-filter> </activity> <activity android:name="com.zoomer.offers.OffersListActivity" > <!-- <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> --> </activity> <activity android:name="com.example.http.SearchNearbyOffersActivity" > <!-- <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> --> </activity> <service android:name="com.example.geo.LocationService" android:enabled="true" /> <receiver android:name="com.example.manyexampleapp.BootReceiver" > <intent-filter> <action android:name="android.intent.action.BOOT_COMPLETED" /> <action android:name="com.example.manyexampleapp.LocationService.LOCATION_BROAD_MSG" /> </intent-filter> </receiver> <meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/app_id" /> </application> </manifest> 改变 <uses-permission android:name="com.example.manyexampleapp.c2dm.permission.RECEIVE" /> 到 <!-- This app has permission to register and receive data message. --> <uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" /> 您收到异常是因为您尚未定义所需的权限 如果应用程序开发后安装了播放服务， 可能会发生 com.google.android.c2dm.permission.RECEIVE 权限已被授予但 android 仍在抱怨同样的错误。 在这种情况下，您必须完全重新安装开发的应用程序才能使此权限发挥作用。 我认为你必须检查 Kotlin 版本兼容性。