[Section 1] compose basic

app/build.gradle.kts

@@ -66,4 +66,14 @@ dependencies {
     androidTestImplementation("androidx.compose.ui:ui-test-junit4")
     debugImplementation("androidx.compose.ui:ui-tooling")
     debugImplementation("androidx.compose.ui:ui-test-manifest")
+    implementation ("androidx.compose.material3:material3:1.1.2")
+
+    // Navigation
+    implementation("androidx.navigation:navigation-compose:2.7.5")
+
+    // ViewModel
+    implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.6.2")
+
+    // LiveData
+    implementation("androidx.compose.runtime:runtime-livedata:1.5.4")
 }

app/src/main/java/com/example/modernprograming_jetpackcompose/MainActivity.kt

@@ -3,18 +3,59 @@ package com.example.modernprograming_jetpackcompose
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
-import androidx.compose.material3.Surface
-import com.example.modernprograming_jetpackcompose.ui.theme.ModernPrograming_JetpackComposeTheme
+import androidx.compose.foundation.layout.Column
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextField
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.State
+import androidx.compose.runtime.livedata.observeAsState
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewmodel.compose.viewModel
 
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContent {
-            ModernPrograming_JetpackComposeTheme {
-                Surface() {
-
-                }
-            }
+            HomeScreen()
         }
     }
-}
+}
+
+@Composable
+fun HomeScreen(viewModel: MainViewModel = viewModel()) {
+    val text3: State<String> = viewModel.liveData.observeAsState("")
+
+    Column {
+        Text(text = text3.value)
+        TextField(value = text3.value, onValueChange = { viewModel.changeValue(it) })
+//        Button(onClick = {
+//            viewModel.changeValue(text3.value)
+//        }) {
+//            Text(text = "클릭")
+//        }
+    }
+}
+
+class MainViewModel : ViewModel() {
+    private val _value = mutableStateOf("Hello World")
+    val value: State<String> = _value
+
+    // LiveData 사용하기
+    private val _liveData = MutableLiveData<String>()
+    val liveData: LiveData<String> get() = _liveData
+
+    fun changeValue(value: String) {
+        _liveData.value = value
+    }
+}
+
+
+@Preview(showBackground = true)
+@Composable
+fun DefaultPreview() {
+
+}