正しい位置情報権限の扱い

パーミッションは必須です

3種類の位置情報パーミッション

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<!-- only if truly needed: -->
<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />

Composeでパーミッションをリクエストする

import androidx.activity.compose.rememberLauncherForActivityResult
import androidx.activity.result.contract.ActivityResultContracts

val launcher = rememberLauncherForActivityResult(
    ActivityResultContracts.RequestMultiplePermissions()
) { result ->
    val fine = result[Manifest.permission.ACCESS_FINE_LOCATION] == true
    val coarse = result[Manifest.permission.ACCESS_COARSE_LOCATION] == true
    // react to the user's choice
}

リクエストを起動する

Button(onClick = {
    launcher.launch(
        arrayOf(
            Manifest.permission.ACCESS_FINE_LOCATION,
            Manifest.permission.ACCESS_COARSE_LOCATION
        )
    )
}) {
    Text("Enable location")
}

すでに許可されているか確認する

import androidx.core.content.ContextCompat
import android.content.pm.PackageManager

fun hasFineLocation(context: Context): Boolean {
    return ContextCompat.checkSelfPermission(
        context,
        Manifest.permission.ACCESS_FINE_LOCATION
    ) == PackageManager.PERMISSION_GRANTED
}

正確な位置情報とおおよその位置情報

// Request both — the system shows a Precise/Approximate toggle
launcher.launch(
    arrayOf(
        Manifest.permission.ACCESS_FINE_LOCATION,
        Manifest.permission.ACCESS_COARSE_LOCATION
    )
)
// If only COARSE comes back granted, you got approximate location.

理由を説明する

import androidx.core.app.ActivityCompat

val shouldExplain = ActivityCompat.shouldShowRequestPermissionRationale(
    activity,
    Manifest.permission.ACCESS_FINE_LOCATION
)
if (shouldExplain) {
    // show a dialog: "We use your location to find nearby stores"
}

恒久的な拒否に対応する

import android.content.Intent
import android.provider.Settings
import android.net.Uri

fun openAppSettings(context: Context) {
    val intent = Intent(
        Settings.ACTION_APPLICATION_DETAILS_SETTINGS,
        Uri.fromParts("package", context.packageName, null)
    )
    context.startActivity(intent)
}

Accompanist Permissionsを使う

import com.google.accompanist.permissions.rememberMultiplePermissionsState

val permissions = rememberMultiplePermissionsState(
    listOf(
        Manifest.permission.ACCESS_FINE_LOCATION,
        Manifest.permission.ACCESS_COARSE_LOCATION
    )
)

if (permissions.allPermissionsGranted) {
    // show the map / read location
} else {
    Button(onClick = { permissions.launchMultiplePermissionRequest() }) {
        Text("Grant location")
    }
}

バックグラウンド位置情報のルール

// Step 1: request foreground first and confirm it's granted.
// Step 2: only then request background:
launcher.launch(
    arrayOf(Manifest.permission.ACCESS_BACKGROUND_LOCATION)
)
// On Android 11+ this sends the user to settings to pick "Allow all the time".

権限で制御する地図

@Composable
fun LocationGate(permissions: MultiplePermissionsState) {
    when {
        permissions.allPermissionsGranted -> MapScreen()
        else -> Column {
            Text("We need location to show nearby places.")
            Button(onClick = { permissions.launchMultiplePermissionRequest() }) {
                Text("Allow location")
            }
        }
    }
}

クイックチェック

まとめ