Multiple choices in a list with compose

Jetpack Compose is Android’s modern toolkit for building native UI. It simplifies and accelerates UI development on Android. Quickly bring your app to life with less code, powerful tools, and intuitive Kotlin APIs.

you have a list with compose it is easier and if you want to do multiple choices in a list with compose you have to use rememberSaveable.

When you use compose you have to set up the gradl like this:

kotlinOptions {
jvmTarget = ‘1.8’
useIR = true
}
buildFeatures {
compose true
}
composeOptions {
kotlinCompilerExtensionVersion “1.0.0-beta08”
}
}

dependencies {

implementation ‘androidx.core:core-ktx:1.5.0’
implementation ‘androidx.appcompat:appcompat:1.3.0’
implementation ‘com.google.android.material:material:1.3.0’
implementation ‘androidx.constraintlayout:constraintlayout:2.0.4’
testImplementation ‘junit:junit:4.13.2’
androidTestImplementation ‘androidx.test.ext:junit:1.1.2’
androidTestImplementation ‘androidx.test.espresso:espresso-core:3.3.0’

// Compose
implementation “org.jetbrains.kotlin:kotlin-stdlib:1.0.0-beta08”
implementation “androidx.activity:activity-compose:1.3.0-beta01”
implementation “androidx.compose.runtime:runtime:1.0.0-beta08”
implementation “androidx.compose.ui:ui:1.0.0-beta08”
implementation “androidx.compose.foundation:foundation:1.0.0-beta08”
implementation “androidx.compose.foundation:foundation-layout:1.0.0-beta08”
implementation “androidx.compose.material:material:1.0.0-beta08”
implementation “androidx.compose.runtime:runtime-livedata:1.0.0-beta08”
implementation “androidx.compose.ui:ui-tooling:1.0.0-beta08”
implementation “com.google.android.material:compose-theme-adapter:1.0.0-beta08”
}
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While remember helps you retain state across recompositions, the state is not retained across configuration changes. For this, you must use rememberSaveable. rememberSaveable automatically saves any value that can be saved in a Bundle. For other values, you can pass in a custom saver object.

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.activity.compose.setContent
import androidx.compose.animation.animateColorAsState
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxHeight
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.itemsIndexed
import androidx.compose.material.Surface
import androidx.compose.material.TabRowDefaults.Divider
import androidx.compose.material.Text
import androidx.compose.material.Checkbox
import androidx.compose.runtime.*
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MyApp {
                MyScreenContent()
            }
        }
    }
}

@Composable
fun MyApp(content: @Composable () -> Unit) {
    Surface(color = Color.White) {
        content()
    }
}

@Composable
fun MyScreenContent(
    names: List<String> = List(15) { "Item #$it" },
    completed: MutableList<Boolean> = MutableList(15) { false }
) {
    Column(modifier = Modifier.fillMaxHeight()) {
        NameList(names, Modifier.weight(1f), completed)
    }
}

@Composable
fun NameList(names: List<String>, modifier: Modifier, completed: MutableList<Boolean>) {
    LazyColumn(modifier = modifier) {
        itemsIndexed(items = names) { index: Int, item: String ->
            Greeting(name = item, completed, index)
            Divider(color = Color.Black)
        }
    }
}

@Composable
fun Greeting(name: String, completedList: MutableList<Boolean>, index: Int) {
    var isSelected by rememberSaveable { mutableStateOf(completedList[index]) }
    val backgroundColor by animateColorAsState(if (isSelected) Color.Blue else Color.Transparent)

    Row {
        Text(
            text = "Hello $name!",
            modifier = Modifier
                .padding(24.dp)
        )
        Checkbox(
                checked = isSelected,
                onCheckedChange = {
                    isSelected = !isSelected
                    completedList[index] = !isSelected
                },
                modifier = Modifier
                    .background(color = backgroundColor)
            )
        }
    }


@Preview("MyScreen preview")
@Composable
fun DefaultPreview() {
    MyApp {
        MyScreenContent()
    }
}

you can download in Github