// LazyColumn Example
// Source code file: MainActivity.kt
// Display numbers 1 to 20 in a LazyColumn.
// A Column renders all items, even the ones
// not in the viewport, whereas a LazyColumn
// only renders items in the viewport for better
// performance. A LazyColumn is scrollable by
// default.

package it372.ssmith.lazycolumn
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.rememberScrollState
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContent {
            Layout( )
        }
    }
}

@Composable
fun Layout( ) {

    // A Column needs a variable to keep track
    // of the scroll state.
    var scrollState = rememberScrollState( )

    LazyColumn(modifier = Modifier
        .padding(20.dp)
        .fillMaxSize( )) {
        repeat(20) {
            item {
                Text(
                    text = "$it",
                    modifier = Modifier
                        .padding(20.dp),
                    fontSize = 50.sp
                )
            }
        }
    }
}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    Layout( )
}