Merge pull request #203 from myofficework000/FirebaseRealtimeDatabase

Firebase realtime database

app/src/main/java/com/example/jetpack_compose_all_in_one/third_party_lib/firebase/realtime_db/Note.kt

@@ -0,0 +1,7 @@
+package com.example.jetpack_compose_all_in_one.third_party_lib.firebase.realtime_db
+
+data class Note(
+    val title: String? = null,
+    val date: String? = null,
+    val content: String? = null
+)

app/src/main/java/com/example/jetpack_compose_all_in_one/third_party_lib/firebase/realtime_db/NoteComposables.kt

@@ -0,0 +1,83 @@
+package com.example.jetpack_compose_all_in_one.third_party_lib.firebase.realtime_db
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.Button
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextField
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+
+@Composable
+fun NoteScreen(viewModel: NoteViewModel) {
+    val notes by viewModel.notes.collectAsState()
+
+    Column {
+        NoteList(notes = notes)
+        UserInput {title, date, content ->
+            viewModel.sendNote(title, date, content)
+        }
+    }
+
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun UserInput(onNoteSent: (String, String, String) -> Unit) {
+    var title by remember { mutableStateOf("") }
+    var date by remember { mutableStateOf("") }
+    var content by remember { mutableStateOf("") }
+
+    Column {
+        TextField(
+            value = title,
+            onValueChange = {title = it},
+            label = { Text(text = "Title")}
+        )
+        TextField(
+            value = date,
+            onValueChange = {date = it},
+            label = { Text(text = "Date")}
+        )
+        TextField(
+            value = content,
+            onValueChange = {content = it},
+            label = { Text(text = "Content")}
+        )
+        Button(onClick = {
+            onNoteSent(title, date, content)
+        }) {
+            Text(text = "Save")
+        }
+    }
+}
+
+@Composable
+fun NoteList(notes: List<Note>) {
+    LazyColumn {
+        items(notes) { note ->
+            NoteItem(note)
+        }
+    }
+}
+
+@Composable
+fun NoteItem(note: Note) {
+    Column(
+        modifier = Modifier
+            .padding(8.dp)
+    ) {
+        Text(text = "Title: ${note.title.orEmpty()}")
+        Text(text = "Date: ${note.date.orEmpty()}")
+        Text(text = note.title.orEmpty())
+    }
+}

app/src/main/java/com/example/jetpack_compose_all_in_one/third_party_lib/firebase/realtime_db/NoteRepository.kt

@@ -0,0 +1,34 @@
+package com.example.jetpack_compose_all_in_one.third_party_lib.firebase.realtime_db
+
+import android.util.Log
+import com.google.firebase.database.DataSnapshot
+import com.google.firebase.database.DatabaseError
+import com.google.firebase.database.FirebaseDatabase
+import com.google.firebase.database.ValueEventListener
+import com.google.firebase.database.ktx.getValue
+
+class NoteRepository {
+
+    private val database = FirebaseDatabase.getInstance().getReference("notes")
+
+    fun saveNote(note: Note) {
+        val noteId = database.push().key
+        noteId?.let {
+            database.child(it).setValue(note)
+        }
+    }
+
+    fun getNoteUpdates(action: (List<Note>) -> Unit) {
+        database.addValueEventListener(object : ValueEventListener {
+            override fun onDataChange(snapshot: DataSnapshot) {
+                val note = snapshot.children.mapNotNull { it.getValue<Note>() }
+                action(note)
+            }
+
+            override fun onCancelled(error: DatabaseError) {
+                Log.i("MessageRepo", "Failed to read notes", error.toException())
+            }
+        })
+    }
+
+}

app/src/main/java/com/example/jetpack_compose_all_in_one/third_party_lib/firebase/realtime_db/NoteViewModel.kt

@@ -0,0 +1,26 @@
+package com.example.jetpack_compose_all_in_one.third_party_lib.firebase.realtime_db
+
+import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+class NoteViewModel(private val repository: NoteRepository) : ViewModel() {
+
+    private val _notes = MutableStateFlow<List<Note>>(emptyList())
+    val notes: StateFlow<List<Note>> = _notes
+
+    init {
+        loadNotes()
+    }
+
+    private fun loadNotes() {
+        repository.getNoteUpdates { note ->
+            _notes.value = note
+        }
+    }
+
+    fun sendNote(title: String, date: String, content: String) {
+        val note = Note(title, date, content)
+        repository.saveNote(note)
+    }
+}

app/src/main/java/com/example/jetpack_compose_all_in_one/third_party_lib/firebase/realtime_db/NoteViewModelFactory.kt

@@ -0,0 +1,13 @@
+package com.example.jetpack_compose_all_in_one.third_party_lib.firebase.realtime_db
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+
+class NoteViewModelFactory(private val repository: NoteRepository) : ViewModelProvider.Factory {
+    override fun <T : ViewModel> create(modelClass: Class<T>): T {
+        if (modelClass.isAssignableFrom(NoteViewModel::class.java)) {
+            return NoteViewModel(repository) as T
+        }
+        throw IllegalArgumentException("Unknown viewmodel class")
+    }
+}