val intent = Intent()
        intent.action = "com.example.firstapp.TEST_BROADCAST_RECEIVER"
       
//        intent.component = ComponentName(
//            packageName,
//            "com.example.firstapp.components.TestBroadcastReceiverActivity"
//        )

        intent.setPackage(packageName)
        
        sendBroadcast(intent)

这样修改就可以收到了。