How to get Context in Jetpack Compose

Question

fun createListItem(itemIndex: Int) {
    Padding(left = 8.dp, right = 8.dp, top = 8.dp, bottom = 8.dp) {
        FlexRow(crossAxisAlignment = CrossAxisAlignment.Center) {
            expanded(1.0f) {
                Text("Item $itemIndex")
            }
            inflexible {
                Button(
                    "Button $itemIndex",
                    style = ContainedButtonStyle(),
                    onClick = {
                        Toast.makeText(
                            this@MainActivity,
                            "Item name $itemIndex",
                            Toast.LENGTH_SHORT
                        ).show()
                    })
            }
        }
    }
}

I try to make Toast in a normal way. but I got the error I tried a lot of multiples source but failed.

Protanopia

You might want to explain exactly what your problem was. I have used Toast in onClick handlers in Compose without a problem. If you were getting a compile error, please provide the complete details of the error. If you were getting a runtime error, please edit your question and post the stack trace. – Rosalba

FYI: while the answers below are valid, the compose team now recommends using Snackbar over Toast in Compose: kotlinlang.slack.com/archives/CJLTWPH7S/…. – Carew

Answer 1

Update March 2021: The previous answer has been deprecated. You should now use:

val context = LocalContext.current

---

Previous answer for reference:

You can access to context with define ambientContext.

Example:

val context = ContextAmbient.current

Kapoor

compose is declarative & as a tree, so if you have complex trees and you need some state that could not provided from root component, you can use ambient or memo – Kapoor

Is there any doc that explains the use of this unaryPlus operator? I can't find anything solid to understand what it is and how to use it @Raka – Jointworm

When I add val context = +ambient(ContextAmbient) to Clickable then get java.lang.IllegalStateException: Composition requires an active composition context – Manton

please show your code (by gist.github.com) @AlexZezekalo – Kapoor

@RakaAdiNugroho I found out that I used a wrong place for getting context: firstly I wrote <code>val context = +ambient(ContextAmbient)<code> inside Clickable and it was the reason of that exception. Then I put this line out of the Clickable to the head of the function and everything became Ok. My fault. – Manton

LocalContext.current can not be used in coroutine scope. This happens typically, when Android forces you to do something in a different thread, than the UI thread. – Tish

I haven't seen this explicitly stated, but it appears Ambient has been removed/rename something else? I found this: lcdsmao.dev/… describing what it was. This seems related: developer.android.com/jetpack/androidx/releases/compose-runtime Renamed Ambients to match the Ambient -> CompositionLocal rename. Ambients used to be named AmbientFoo, now CompositionLocals are named LocalFoo. (I2d55d) I found ambients in old sample code: github.com/android/compose-samples/tree/main/Jetchat – Spurn

Answer 2

ContextAmbient and AmbientContext has been deprecated.

You can replace them with LocalContext

Example:

val context = LocalContext.current

Alerion

How can I use this val context = LocalContext.current as a global variable in my Activity? – Edelweiss

@gauravkumar I think the most you can do is declaring it as the first line in setContent method because it only works inside composable function. If you need a context outside setContent, just use this. – Ripply

Android changes faster than the speed of light.😁. I have never used ContextAmbient and AmbientContext in my life. – Riobard

Answer 3

ContextAmbient.current is deprecated as of alpha-09.

AmbientContext.current is deprecated. I think as of alpha-11.

LocalContext.current is how you get the context in a composable now.

Isogamy

Answer 4

The way to do this has been updated. It's now:

val context = LocalContext.current

LocalContext docs

Misconstruction

Answer 5

LocalContext.current - is the right approach. But the problem is you can't use LocalContext.current inside @Composable function

You need to create separate function to use Context

Sample code

@Composable
fun DoneButton() {
    val context = LocalContext.current
    Button(onClick = { showToast(context, "Button clicked")}) {
        Text(name = "Done")
    }
}

fun showToast(context: Context, msg: String) {
    Toast.makeText(context, msg, Toast.LENGTH_LONG).show()
}

Joyajoyan

Answer 6

ContextAmbient and AmbientContext is deprecated

Update

Now Jetpack way to do this has been updated. It's now:

val context = LocalContext.current

Tribute

What about Application context? – Monied

@Monied Once you have the local context, context.getApplicationContext() – Hamza

Answer 7

ContextAmbient.current has been deprecated, use val context = LocalContext.current instead.

Piccard

Answer 8

Some useful if you need get context as Activity from last Android Studio template:

val view = LocalView.current
(view.context as Activity).<activity method>

Better solution

fun Context.getActivity(): Activity? = when (this) {
    is Activity -> this
    is ContextWrapper -> baseContext.getActivity()
    else -> null
}

val activity = LocalContext.current.getActivity()

Hospers

It is not safe as the context may not be an activity. – Pareto

@EmadRazavi Agree, I updated my answer – Hospers

Answer 9

For getting context in jetpack compose:

val context = ContextAmbient.current

Working on 0.1.0-dev14

How to use it in TOAST:

@Composable
fun cardViewImplementer(item: Int) {
   val context = ContextAmbient.current
   Card(
     shape = RoundedCornerShape(10.dp),
     modifier = Modifier.padding(10.dp)
   ) {
     Box(
        modifier = Modifier
            .fillMaxWidth()
            .drawShadow(5.dp)
            .clickable(onClick = {
                Toast.makeText(context, "Clicked $item", Toast.LENGTH_SHORT).show()
            }), children = {

        })
}

For accessing the Resource:

Text("Read this string: "+context.getString(R.string.name))

Necrotomy

Answer 10

Issues with compose_version = '1.0.0-alpha12' ? AmbientContext is now LocalContext

Michaelamichaele

Answer 11

val context = LocalContext.current
Toast.makeText(context,"Hello Compose",Toast.LENGTH_LONG).show()

Dubious

Answer 12

You can use the LocalUriHandler:

val handler = LocalUriHandler.currenthandler 

Button( 
    onClick = { handler.openUri("https://www.stackoverflow.com") } 
) {    
     Text("Open") 
} 

Exocarp