Alert dialogs help developers to show important messages or updates to mobile app users. In this Jetpack Compose tutorial, let’s learn how to show a simple alert dialog.
AlertDialog is the function we have to use for this purpose. It helps to show an alert dialog with buttons.
@Composable
fun AlertExample() {
val dialogVisibility = remember { mutableStateOf(true) }
if (dialogVisibility.value) {
AlertDialog(
onDismissRequest = {
dialogVisibility.value = false
},
title = {
Text(text = " Alert Title")
},
text = {
Text("This is a Jetpack Compose tutorial on AlertDialog.")
},
buttons = {
Row(
modifier = Modifier.padding(10.dp),
horizontalArrangement = Arrangement.Center
) {
Button(
modifier = Modifier.fillMaxWidth(),
onClick = { dialogVisibility.value = false }
) {
Text("Okay")
}
}
}
)
}
}
In the above code snippet, the dialogVisibilty variable controls the visibility of the AlertDialog. The use of title, text, buttons, and onDismissRequest parameters is self-explanatory.
Following is the complete code for this AlertDialog example.
package com.example.myapplication
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
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.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.example.myapplication.ui.theme.MyApplicationTheme
class MainActivity : ComponentActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
MyApplicationTheme {
Surface(
color = MaterialTheme.colors.background,
modifier = Modifier.fillMaxWidth().fillMaxHeight()
) {
AlertExample()
}
}
}
}
}
@Composable
fun AlertExample() {
val dialogVisibility = remember { mutableStateOf(true) }
if (dialogVisibility.value) {
AlertDialog(
onDismissRequest = {
dialogVisibility.value = false
},
title = {
Text(text = " Alert Title")
},
text = {
Text("This is a Jetpack Compose tutorial on AlertDialog.")
},
buttons = {
Row(
modifier = Modifier.padding(10.dp),
horizontalArrangement = Arrangement.Center
) {
Button(
modifier = Modifier.fillMaxWidth(),
onClick = { dialogVisibility.value = false }
) {
Text("Okay")
}
}
}
)
}
}
@Preview(showBackground = true)
@Composable
fun DefaultPreview() {
MyApplicationTheme {
AlertExample()
}
}Following is the output.
That’s how we show a AlertDialog in Jetpack Compose.
