Confirming exit from app

app/src/main/java/org/koitharu/kotatsu/main/ui/MainActivity.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.MenuItem
 import android.view.View
 import android.view.ViewGroup.MarginLayoutParams
+import android.widget.Toast
 import androidx.activity.result.ActivityResultCallback
 import androidx.annotation.IdRes
 import androidx.appcompat.view.ActionMode
@@ -20,6 +21,8 @@ import com.google.android.material.appbar.AppBarLayout.LayoutParams.*
 import com.google.android.material.navigation.NavigationBarView
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import org.koin.android.ext.android.get
 import org.koin.androidx.viewmodel.ext.android.viewModel
@@ -60,6 +63,8 @@ class MainActivity :
 	View.OnFocusChangeListener,
 	SearchSuggestionListener, NavigationBarView.OnItemSelectedListener {
 
+	private var isConfirmingExit: Boolean = false
+
 	private val viewModel by viewModel<MainViewModel>()
 	private val searchSuggestionViewModel by viewModel<SearchSuggestionViewModel>()
 	private val voiceInputLauncher = registerForActivityResult(VoiceInputContract(), VoiceInputCallback())
@@ -131,6 +136,7 @@ class MainActivity :
 				setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
 				runOnCommit { onSearchClosed() }
 			}
+			shouldHandleExitConfirmation() -> lifecycleScope.launch { resetExitConfirmation() }
 			else -> super.onBackPressed()
 		}
 	}
@@ -147,6 +153,19 @@ class MainActivity :
 		return super.onOptionsItemSelected(item)
 	}
 
+	private suspend fun resetExitConfirmation() {
+		isConfirmingExit = true
+		val toast = Toast.makeText(this, R.string.confirm_exit, Toast.LENGTH_LONG)
+		toast.show()
+		delay(2000)
+		toast.cancel()
+		isConfirmingExit = false
+	}
+
+	private fun shouldHandleExitConfirmation(): Boolean {
+		return !isConfirmingExit
+	}
+
 	override fun onClick(v: View) {
 		when (v.id) {
 			R.id.fab -> viewModel.openLastReader()

app/src/main/res/values/strings.xml

@@ -337,4 +337,5 @@
 	<string name="changelog">Changelog</string>
 	<string name="explore">Explore</string>
 	<string name="tools">Tools</string>
+	<string name="confirm_exit">Press back again to exit</string>
 </resources>