TODO

todo.kt

package com.example.androidvsios

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.animation.AnimatedVisibility
import androidx.compose.animation.ExperimentalAnimationApi
import androidx.compose.foundation.Image
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.material.*
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Add
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.snapshots.SnapshotStateList
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.ColorFilter
import androidx.compose.ui.unit.dp
import com.example.androidvsios.ui.theme.AndroidvsIOSTheme

@OptIn(ExperimentalAnimationApi::class)
class MainActivity : ComponentActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        window.statusBarColor = android.graphics.Color.parseColor("#FE9F71")

        setContent {

            val todosState = remember { initialTodos() }

            AndroidvsIOSTheme {
                Scaffold(
                    topBar = {
                        AddingTopAppBar(
                            onClick = { addItem(todosState) }
                        )
                    },
                    content = {
                        LazyColumn {
                            items(todosState) { todo ->
                                ListItem(
                                    todo = todo,
                                    onClick = { expandItem(todo, todosState) }
                                )
                            }
                        }
                    }
                )
            }
        }
    }

    @Composable
    private fun AddingTopAppBar(
        onClick: () -> Unit
    ) {
        TopAppBar(
            backgroundColor = Color(0xFFFE9F71)
        ) {
            Spacer(Modifier.weight(1f))
            Text(
                modifier = Modifier.align(Alignment.CenterVertically),
                text = "TO DO",
                color = Color.White,
                style = MaterialTheme.typography.h4
            )
            Spacer(Modifier.weight(1f))
            Image(
                modifier = Modifier
                    .padding(end = 8.dp)
                    .align(Alignment.CenterVertically)
                    .clickable(onClick = onClick),
                imageVector = Icons.Filled.Add,
                contentDescription = "add",
                colorFilter = ColorFilter.tint(Color.White)
            )
        }
    }

    @Composable
    private fun ListItem(
        todo: Todo,
        onClick: () -> Unit
    ) {
        Surface(
            Modifier
                .clickable(onClick = onClick)
                .fillMaxWidth()
                .padding(start = 16.dp, end = 16.dp, top = 16.dp),
            color = todo.color,
            elevation = 4.dp
        ) {
            Column(
                modifier = Modifier.padding(16.dp)
            ) {
                Text(
                    text = todo.title,
                    color = Color.White,
                    style = MaterialTheme.typography.body1
                )
                AnimatedVisibility(visible = todo.expanded) {
                    Text(
                        modifier = Modifier.padding(top = 8.dp),
                        text = todo.description,
                        color = Color.White,
                        style = MaterialTheme.typography.caption
                    )
                }
            }
        }
    }

    private fun expandItem(
        currentItem: Todo,
        listItems: SnapshotStateList<Todo>
    ) {
        val newList: List<Todo> = listItems.map { item ->
            if (currentItem != item) item
            else item.copy(expanded = !item.expanded)
        }
        listItems.clear()
        listItems.addAll(newList)
    }

    private fun addItem(listItems: SnapshotStateList<Todo>) {
        listItems.add(
            Todo(
                title = "NEUE AUFGABE",
                description = "Es gibt viel zu tun",
                expanded = false,
                color = Color(0xFFbc8cbe)
            )
        )
    }
}

fun initialTodos() = mutableStateListOf(
    Todo(
        title = "PUTZEN",
        description = "Am besten mit dem Staubsauger",
        expanded = false,
        color = Color(0xFFF48786L)
    ),
    Todo(
        title = "EINKAUFEN",
        description = "Essen und Trinken",
        expanded = false,
        color = Color(0xFFF39AC0)
    )
)

data class Todo(
    val title: String,
    val description: String,
    val expanded: Boolean,
    val color: Color
)