andoid的theme报错，求帮忙 ?报错

报错： java.lang.RuntimeException: Unable to start receiver com.example.broadcastbestpractice.ForceOfflineReceiver: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme
(or descendant) with this activity.

全部活动继承的是import android.support.v7.app.AppCompatActivity;

 /**
 * Created by Administrator on 2016/6/15.
 */
public class BaseActivity extends AppCompatActivity {

配置文件：

     package="com.example.broadcastbestpractice">

    <!-- To auto-complete the email text field in the login form with the user's emails -->
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.READ_PROFILE" />
    <uses-permission android:name="android.permission.READ_CONTACTS" />
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat">

        <activity android:name=".LoginActivity"
            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=".MainActivity">

        </activity>

        <receiver android:name=".ForceOfflineReceiver">
            <intent-filter>
                <action android:name="com.example.broadcastbestpractice.FORCE_OFFLINE"/>
            </intent-filter>

        </receiver>
    </application>

接收器：

 package com.example.broadcastbestpractice;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;

import android.support.v7.app.AlertDialog;
import android.view.WindowManager;

/**
 * Created by Administrator on 2016/6/15.
 */
public class ForceOfflineReceiver extends BroadcastReceiver {
    @Override

    public void onReceive(final Context context, Intent intent) {
       AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(context);

        dialogBuilder.setTitle("Warning");
        dialogBuilder.setMessage("You are forced to be offline.Please try to login again.");

        dialogBuilder.setCancelable(false);
        dialogBuilder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                ActivityCollector.finishAll();

                Intent intent = new Intent(context,LoginActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(intent);
            }
        });

        AlertDialog alertDialog = dialogBuilder.create();//创建对话框

        //设置对话框类型
        alertDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
        alertDialog.show();
    }
}