我有一个Arduino,它将读数推送到数据库,我有一个Android应用程序,可以检索读数并在TextView中显示它.
我的应用程序一直在获取TextView的所有内容,键和值.
我如何才能解决这个问题并且只显示最后一个值?
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// Initialize Firebase App
FirebaseApp.initializeApp(this)
// Inflate layout
Binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(R.layout.activity_landing)
// Initialize Firebase Database query
val query = FirebaseDatabase.getInstance("https://voltageread-22aa9-default-rtdb.firebaseio.com/")
.reference
.orderByKey()
.limitToLast(1)
// Fetch data from Firebase Realtime Database and save it in a variable
query.addListenerForSingleValueEvent(object : ValueEventListener {
override fun onDataChange(snapshot: DataSnapshot) {
if (snapshot.exists() && snapshot.value != null) {
val lastChildSnapshot = snapshot.children.lastOrNull()
if (lastChildSnapshot != null) {
val data = lastChildSnapshot.value.toString()
if (!data.isNullOrEmpty()) {
Log.d("Firebase", "Data received: $data ")
// Update the UI with the received data
Binding.voltage.text = data.substringAfter('=')
}
}
}
}
override fun onCancelled(error: DatabaseError) {
Log.e("Firebase", "Data fetching cancelled: ${error.message} ")
}
})
我试过使用内置的电池板,但似乎什么都不起作用