Android 14 之 动态注册Broadcast必须声明exported属性

以 Android 14 为目标并动态注册广播应用和服务需要指定exported属性

下面是Android版本对于Broadcast的限制演进。

版本	改动点	目的
Android 8	不再支持在配置清单中注册任意隐式Intent的Receiver	避免频繁地广播Intent，导致应用频繁唤醒，过度耗电
Android 13以前	设备上的任何应用都可以向动态注册的接收器发送广播	避免静态注册广播的问题
Android 13	应用可以通过动态代码声明RECEIVER_EXPORTED或 RECEIVER_NOT_EXPORTED是否接收外部程序发送的广播	增加了拒绝选择项，提高运行时接收器的安全性
Android 14	必须得要为动态注册的广播接收器声明是否接收外部广播，否则系统就会抛出异常	进一步收缩广播安全性

• 在 Android 13以前的版本中，设备上的任何应用都可以向动态注册的广播接收器发送广播，除非该接收器受签名权限的保护。

 // This broadcast receiver should be able to receive broadcasts from other apps.
    // This option causes the same behavior as setting the broadcast receiver's
    // "exported" attribute to true in your app's manifest.
  context.registerReceiver(sharedBroadcastReceiver, intentFilter,
        RECEIVER_EXPORTED)

    // For app safety reasons, this private broadcast receiver should **NOT**
    // be able to receive broadcasts from other apps.
    context.registerReceiver(privateBroadcastReceiver, intentFilter,
        RECEIVER_NOT_EXPORTED)

测试（Android 14 不注册情况下会报以下错误）

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.cao.myapplication, PID: 19589
    java.lang.SecurityException: com.cao.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)
        at android.os.Parcel.createException(Parcel.java:3041)
        at android.os.Parcel.readException(Parcel.java:3024)
        at android.os.Parcel.readException(Parcel.java:2966)
        at android.app.IActivityManager$Stub$Proxy.registerReceiverWithFeature(IActivityManager.java:5393)
        at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:1851)
        at android.app.ContextImpl.registerReceiver(ContextImpl.java:1791)
        at android.app.ContextImpl.registerReceiver(ContextImpl.java:1779)
        at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:754)
        at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:754)
        at com.cao.myapplication.MainActivity.onCreate$lambda$0(MainActivity.kt:36)

• 正常示例

val br: BroadcastReceiver = MyBroadcastReceiver()
val filter = IntentFilter("com.example.myintentfilter")
val listenToBroadcastsFromOtherApps = false
val receiverFlags = if (listenToBroadcastsFromOtherApps) {
    ContextCompat.RECEIVER_EXPORTED
} else {
    ContextCompat.RECEIVER_NOT_EXPORTED
}
ContextCompat.registerReceiver(context, br, filter, receiverFlags)