Hide error when text is entered (#14)

app/src/main/java/gq/kirmanak/mealient/ui/ViewExtensions.kt

@@ -4,12 +4,15 @@ import android.app.Activity
 import android.os.Build
 import android.view.View
 import android.view.WindowInsets
+import android.widget.TextView
 import androidx.annotation.RequiresApi
 import androidx.appcompat.app.AppCompatActivity
+import androidx.core.widget.doAfterTextChanged
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.asLiveData
 import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.channels.ChannelResult
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.channels.onClosed
 import kotlinx.coroutines.channels.onFailure
@@ -22,9 +25,7 @@ fun SwipeRefreshLayout.refreshesLiveData(): LiveData<Unit> {
     val callbackFlow: Flow<Unit> = callbackFlow {
         val listener = SwipeRefreshLayout.OnRefreshListener {
             Timber.v("Refresh requested")
-            trySend(Unit)
-                .onFailure { Timber.e(it, "refreshesFlow: can't send refresh callback") }
-                .onClosed { Timber.e(it, "refreshesFlow: flow has been closed") }
+            trySend(Unit).logErrors("refreshesFlow")
         }
         Timber.v("Adding refresh request listener")
         setOnRefreshListener(listener)
@@ -60,4 +61,22 @@ fun AppCompatActivity.setActionBarVisibility(isVisible: Boolean) {
     Timber.v("setActionBarVisibility() called with: isVisible = $isVisible")
     supportActionBar?.apply { if (isVisible) show() else hide() }
         ?: Timber.w("setActionBarVisibility: action bar is null")
+}
+
+@ExperimentalCoroutinesApi
+fun TextView.textChangesFlow(): Flow<CharSequence?> = callbackFlow {
+    Timber.v("textChangesFlow() called")
+    val textWatcher = doAfterTextChanged {
+        trySend(it).logErrors("textChangesFlow")
+    }
+    awaitClose {
+        Timber.d("textChangesFlow: flow is closing")
+        removeTextChangedListener(textWatcher)
+    }
+}
+
+fun <T> ChannelResult<T>.logErrors(methodName: String): ChannelResult<T> {
+    onFailure { Timber.e(it, "$methodName: can't send event") }
+    onClosed { Timber.e(it, "$methodName: flow has been closed") }
+    return this
 }

app/src/main/java/gq/kirmanak/mealient/ui/auth/AuthenticationFragment.kt

@@ -9,14 +9,20 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
 import androidx.lifecycle.Observer
+import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
 import com.google.android.material.textfield.TextInputLayout
 import dagger.hilt.android.AndroidEntryPoint
 import gq.kirmanak.mealient.R
 import gq.kirmanak.mealient.data.auth.impl.AuthenticationError.*
 import gq.kirmanak.mealient.databinding.FragmentAuthenticationBinding
+import gq.kirmanak.mealient.ui.textChangesFlow
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.first
 import timber.log.Timber
 
+@ExperimentalCoroutinesApi
 @AndroidEntryPoint
 class AuthenticationFragment : Fragment() {
     private var _binding: FragmentAuthenticationBinding? = null
@@ -107,13 +113,23 @@ class AuthenticationFragment : Fragment() {
         Timber.v("checkIfInputIsEmpty() called with: input = $input, inputLayout = $inputLayout, errorText = $errorText")
         val text = input.text?.toString()
         Timber.d("Input text is \"$text\"")
-        if (text.isNullOrBlank()) {
+        if (text.isNullOrEmpty()) {
             inputLayout.error = errorText()
+            viewLifecycleOwner.lifecycleScope.launchWhenResumed {
+                waitUntilNotEmpty(input)
+                inputLayout.error = null
+            }
             return null
         }
         return text
     }
 
+    private suspend fun waitUntilNotEmpty(input: EditText) {
+        Timber.v("waitUntilNotEmpty() called with: input = $input")
+        input.textChangesFlow().filterNotNull().first { it.isNotEmpty() }
+        Timber.v("waitUntilNotEmpty() returned")
+    }
+
     override fun onDestroyView() {
         super.onDestroyView()
         Timber.v("onDestroyView() called")