Android V 广播注册和配置注意事项问题

现象

在Android V平台上，应用注册非Protected广播时，如果没有加导出flag会抛出异常导致进程crash。

E/AndroidRuntime: FATAL EXCEPTION: main

        java.lang.SecurityException: com.demo.myapplication: One of RECEIVER_EXPORTED or RECEIVER_NOT_EXPORTED should be specified when a receiver isn't being registered exclusively for system broadcasts

                at android.os.Parcel.createExceptionOrNull(Parcel.java:3057)

官方的protected-broadcast参考

AndroidManifest.xml - OpenGrok cross reference for /frameworks/base/core/res/AndroidManifest.xml (aospxref.com)

平台规则

在Android 13 或更高版本为目标平台的应用内，在调用registerReceiver()时必须指定导出行为（exported true or false），如果未指定导出行为，可能会导致应用崩溃。

android:exported="true"

参考：广播概览  |  Background work  |  Android Developers

代码实现

接收广播

应用可以通过两种方式接收广播：通过清单声明的接收器 和上下文注册的接收器

1、【静态】声明广播接收器法

1、指定 <receiver> 元素。

<!-- If this receiver listens for broadcasts sent from the system or fromother apps, even other apps that you own, set android:exported to "true". -->
<receiver android:name=".MyBroadcastReceiver" android:exported="false"><intent-filter><action android:name="APP_SPECIFIC_BROADCAST" /></intent-filter>
</receiver>

intent 过滤器指定您的接收器所订阅的广播操作。 

2、创建 BroadcastReceiver 子类并实现 onReceive(Context, Intent)。通过 以下示例中的广播接收器会记录日志并显示内容 以下内容：

public class MyBroadcastReceiver extends BroadcastReceiver {private static final String TAG = "MyBroadcastReceiver";@Overridepublic void onReceive(Context context, Intent intent) {StringBuilder sb = new StringBuilder();sb.append("Action: " + intent.getAction() + "\n");sb.append("URI: " + intent.toUri(Intent.URI_INTENT_SCHEME).toString() + "\n");String log = sb.toString();Log.d(TAG, log);ActivityNameBinding binding =ActivityNameBinding.inflate(layoutInflater);val view = binding.root;setContentView(view);Snackbar.make(view, log, Snackbar.LENGTH_LONG).show();}}

系统软件包管理器会在应用安装时注册接收器。 然后，接收器将成为应用的单独入口点，这意味着 确保系统可以启动应用并传递广播（如果应用未 。

系统会创建一个新的 BroadcastReceiver 组件 对象来处理它接收的每个广播。仅此对象有效 在调用 onReceive(Context, Intent) 期间有效。将代码添加到 返回时，系统会将该组件 活动状态。

2、【动态】上下文注册的接收器（常用）

上下文注册的接收器可以接收广播，前提是它们的注册 上下文有效。例如，如果您在一个 Activity 上下文，只要 activity 不被销毁，您就会收到广播。如果您 注册到应用上下文，那么，只要应用 正在运行。

先创建 BroadcastReceiver和IntentFilter，再通过调用registerReceiver()方法来注册接收器。
 

RECEIVER_EXPORTED 导出flag定义

源码：

Context.java - OpenGrok cross reference for /frameworks/base/core/java/android/content/Context.java (aospxref.com)

    /*** <p>For apps targeting {@link android.os.Build.VERSION_CODES#UPSIDE_DOWN_CAKE},* either {@link #RECEIVER_EXPORTED} or {@link #RECEIVER_NOT_EXPORTED} must be* specified if the receiver is not being registered for <a* href="{@docRoot}guide/components/broadcasts#system-broadcasts">system broadcasts</a>* or a {@link SecurityException} will be thrown. See {@link* #registerReceiver(BroadcastReceiver, IntentFilter, int)} to register a receiver with* flags.*//*** Flag for {@link #registerReceiver}: The receiver can receive broadcasts from other Apps.* Has the same behavior as marking a statically registered receiver with "exported=true"*/public static final int RECEIVER_EXPORTED = 0x2;/*** @deprecated Use {@link #RECEIVER_NOT_EXPORTED} or {@link #RECEIVER_EXPORTED} instead.* @hide*/@Deprecated@TestApipublic static final int RECEIVER_EXPORTED_UNAUDITED = RECEIVER_EXPORTED;/*** Flag for {@link #registerReceiver}: The receiver cannot receive broadcasts from other Apps.* Has the same behavior as marking a statically registered receiver with "exported=false"*/public static final int RECEIVER_NOT_EXPORTED = 0x4;

整改方案※

运行时注册的广播接收器必须指定导出行为。

1、查看服务或应用内是否注册动态广播，且该广播属于非Procted系统广播

protected-broadcast

2、按照监听情况，在调用registerReceiver时添加标志位参数RECEIVER_EXPORTED 或RECEIVER_NOT_EXPORTED

//RECEIVER_EXPORTED or RECEIVER_NOT_EXPORTEDBroadcastReceiver br = new MyBroadcastReceiver();//系统广播
//写法1
//IntentFilter filter = new IntentFilter();
//filter.addAction(CarrierConfigManager.ACTION_CARRIER_CONFIG_CHANGED);//写法2
//IntentFilter intentFilter = new IntentFilter(TelephonyIntents.ACTION_SIM_STATE_CHANGED);
//registerReceiver(mSimStateReceiver, intentFilter);//写法3：自定义
IntentFilter filter = new IntentFilter("com.demo.myintentfilter");
boolean isListenBroadcaseFromOtherAps = false;int receiverFlags;
if (isListenBroadcaseFromOtherAps) {receiverFlags = RECEIVER_EXPORTED;
} else {receiverFlags = RECEIVER_NOT_EXPORTED;
}ContextCompat.registerReceiver(context, br, filter, receiverFlags)

源码kotlin参考：

 源码Java参考：

ScreenshotHelper.java - OpenGrok cross reference for /frameworks/base/core/java/com/android/internal/util/ScreenshotHelper.java (aospxref.com)

    public ScreenshotHelper(Context context) {mContext = context;IntentFilter filter = new IntentFilter(ACTION_USER_SWITCHED);mContext.registerReceiver(mBroadcastReceiver, filter, Context.RECEIVER_EXPORTED);}

如上参考：Android 14 之 动态注册Broadcast必须声明exported属性以 Android 14 为目标并动态 - 掘金 (juejin.cn)