Sliding Bottom Sheet in Android using Jetpack Compose

Bottom Sheet is a material design component that slides up from the bottom of the screen to display additional content for the application. It is like a message that is invoked or appears upon user actions. A Bottom Sheet is widely used in modern applications. For example, a Bottom Sheet appears inside a game where there are in-app purchases to be made.

In this article, we will show you how you could create a Simple Sliding Bottom Sheet in Android using Jetpack Compose. Follow the below steps once the IDE is ready.

Step by Step Implementation

Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. While choosing the template, select Empty Compose Activity. If you do not find this template, try upgrading the Android Studio to the latest version. We demonstrated the application in Kotlin, so make sure you select Kotlin as the primary language while creating a New Project.

Step 2: Working with the MainActivity.kt file

Go to the MainActivity.kt file and refer to the following code. Below is the code for the MainActivity.kt file. Comments are added inside the code to understand the code in more detail.

Kotlin

package com.geeksforgeeks.jcbottomsheet

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.runtime.Composable
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import kotlinx.coroutines.launch

class MainActivity : ComponentActivity() {
    @ExperimentalMaterialApi
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            // Calling the composable function
            // to display element and its contents
            MainContent()
        }
    }
}

// Creating a composable
// function to display Top Bar
@ExperimentalMaterialApi
@Composable
fun MainContent() {
    Scaffold(
        topBar = { TopAppBar(title = { Text("GFG | Bottom Sheet", color = Color.White) }, backgroundColor = Color(0xff0f9d58)) },
        content = { MyContent() }
    )
}

// Creating a composable function to
// create a Button and a Bottom Sheet
// Calling this function as content
// in the above function
@ExperimentalMaterialApi
@Composable
fun MyContent(){

    // Declaring a Boolean value to
    // store bottom sheet collapsed state
    val bottomSheetScaffoldState = rememberBottomSheetScaffoldState(bottomSheetState =
      BottomSheetState(BottomSheetValue.Collapsed))

    // Declaring Coroutine scope
    val coroutineScope = rememberCoroutineScope()

    // Creating a Bottom Sheet
    BottomSheetScaffold(
        scaffoldState = bottomSheetScaffoldState,
        sheetContent =  {
            Box(Modifier.fillMaxWidth().height(200.dp).background(Color(0XFF0F9D58))) {
                Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally) {
                    Text(text = "Hello Geek!", fontSize = 20.sp, color = Color.White)
                }
            }
        },
        sheetPeekHeight = 0.dp
    ){}

    Column(
        Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally) {

        // Creating a button that changes
        // bottomSheetScaffoldState value upon click
        // when bottomSheetScaffoldState is collpased,
        // it expands and vice-versa
        Button(onClick = {
            coroutineScope.launch {
                if (bottomSheetScaffoldState.bottomSheetState.isCollapsed){
                    bottomSheetScaffoldState.bottomSheetState.expand()
                }else{
                    bottomSheetScaffoldState.bottomSheetState.collapse()
                }
            }
        }, colors = ButtonDefaults.buttonColors(backgroundColor = Color(0XFF0F9D58))) {
            Text(text = "Click Me", color = Color.White)
        }
    }
}

// For displaying preview in
// the Android Studio IDE emulator
@ExperimentalMaterialApi
@Preview(showBackground = true)
@Composable
fun DefaultPreview() {
    MainContent()
}

Output:

You can see in the below video that the Bottom Sheet slides up when the Button is clicked.