Android Jetpack Compose – Close Application By Button
When we are implementing an AlertDialog within the android application for asking for permissions within the android application. In that case, we provide 2 options either to grant permissions or close the application. In this article, we will take a look at How to quit an android application programmatically using Jetpack Compose.
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: Adding a new color to the Color.kt file
Navigate to app > java > your app’s package name > ui.theme > Color.kt file and add the below code to it.
Kotlin
package com.example.newcanaryproject.ui.theme import androidx.compose.ui.graphics.Color val Purple200 = Color( 0xFF0F9D58 ) val Purple500 = Color( 0xFF0F9D58 ) val Purple700 = Color( 0xFF3700B3 ) val Teal200 = Color( 0xFF03DAC5 ) // on below line we are adding different colors val greenColor = Color( 0xFF0F9D58 ) |
Step 3: 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.example.newcanaryproject import android.app.Activity import android.content.Context import android.content.pm.ActivityInfo import android.hardware.camera2.CameraManager import android.net.ConnectivityManager import android.os.Build import android.os.Bundle import android.provider.Settings.* import android.widget.Toast import androidx.activity.ComponentActivity import androidx.activity.compose.setContent import androidx.annotation.RequiresApi import androidx.compose.foundation.layout.* import androidx.compose.material.* import androidx.compose.runtime.Composable import androidx.compose.runtime.mutableStateOf import androidx.compose.runtime.remember import androidx.compose.ui.Alignment import androidx.compose.ui.Modifier import androidx.compose.ui.graphics.Color import androidx.compose.ui.platform.LocalContext import androidx.compose.ui.text.TextStyle import androidx.compose.ui.text.font.FontFamily import androidx.compose.ui.text.font.FontWeight import androidx.compose.ui.text.style.TextAlign import androidx.compose.ui.unit.dp import androidx.compose.ui.unit.sp import androidx.core.content.ContextCompat.getSystemService import com.example.newcanaryproject.ui.theme.NewCanaryProjectTheme import com.example.newcanaryproject.ui.theme.greenColor import java.lang.System.exit class MainActivity : ComponentActivity() { @RequiresApi (Build.VERSION_CODES.M) override fun onCreate(savedInstanceState: Bundle?) { super .onCreate(savedInstanceState) setContent { NewCanaryProjectTheme { // on below line we are specifying background // color for our application Surface( // on below line we are specifying // modifier and color for our app modifier = Modifier.fillMaxSize(), color = MaterialTheme.colors.background ) { // on the below line we are specifying // the theme as the scaffold. Scaffold( // in scaffold we are specifying the top bar. topBar = { // inside top bar we are // specifying background color. TopAppBar(backgroundColor = greenColor, // along with that we are // specifying title for our top bar. title = { // in the top bar we are // specifying tile as a text Text( // on below line we are specifying // text to display in top app bar. text = "GFG" , // on below line we are specifying // modifier to fill max width. modifier = Modifier.fillMaxWidth(), // on below line we are specifying // text alignment. textAlign = TextAlign.Center, // on below line we are specifying // color for our text. color = Color.White ) }) }) { // on below line we are calling our // method to display UI closeApplication(LocalContext.current) } } } } } } @Composable fun closeApplication(context: Context) { // on below line we are creating a column, Column( // on below line we are // adding a modifier to it, modifier = Modifier .fillMaxSize() // on below line we are // adding a padding. .padding(all = 30 .dp), horizontalAlignment = Alignment.CenterHorizontally, verticalArrangement = Arrangement.Center, ) { // on below line we are creating a text // for displaying torch status. Text( text = "Close Application Programmatically in Android" , // on below line we are // displaying a text color color = Color.Black, // on below line we are // setting font weight fontWeight = FontWeight.Bold, // on below line we are // setting font family fontFamily = FontFamily.Default, // on below line adding // text alignment textAlign = TextAlign.Center, // on below line we are setting // font size and padding. fontSize = 20 .sp, modifier = Modifier.padding( 5 .dp) ) // on below line we are adding a spacer Spacer(modifier = Modifier.height( 20 .dp)) // on below line creating a button // to close application Button(onClick = { // on below line we are creating and // initializing variable for activity val activity: MainActivity = MainActivity() // on below line we are finishing activity. activity.finish() java.lang.System.exit( 0 ) }) { Text(text = "Close Application" ) } } } |
Now run your application to see the output of it.
Output:
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