Implement right-to-left support

Author: farmerbb

app/src/main/AndroidManifest.xml

@@ -42,6 +42,7 @@
         android:icon="@mipmap/ic_launcher"
         android:label="${appName}"
         android:theme="@style/Theme.Notepad"
+        android:supportsRtl="true"
         tools:ignore="AppLinkUrlError">
 
         <activity-alias

app/src/main/java/com/farmerbb/notepad/data/PreferenceManager.kt

@@ -89,6 +89,7 @@ class PreferenceManager private constructor(
     val showDate get() = Prefs.ShowDate.asFlow
     val directEdit get() = Prefs.DirectEdit.asFlow
     val markdown get() = Prefs.Markdown.asFlow
+    val rtlSupport get() = Prefs.RtlSupport.asFlow
     val firstRunComplete get() = Prefs.FirstRun.mapToFlow(::toBoolean)
     val firstViewComplete get() = Prefs.FirstLoad.mapToFlow(::toBoolean)
     val showDoubleTapMessage get() = Prefs.ShowDoubleTapMessage.asFlow

app/src/main/java/com/farmerbb/notepad/model/Prefs.kt

@@ -29,6 +29,7 @@ object PrefKeys {
     val ShowDate = booleanPreferencesKey("show_date")
     val DirectEdit = booleanPreferencesKey("direct_edit")
     val Markdown = booleanPreferencesKey("markdown")
+    val RtlSupport = booleanPreferencesKey("rtl_support")
     val ShowDoubleTapMessage = booleanPreferencesKey("show_double_tap_message")
     val FirstRun = intPreferencesKey("first-run")
     val FirstLoad = intPreferencesKey("first-load")
@@ -75,6 +76,11 @@ object Prefs {
         defaultValue = false
     )
 
+    object RtlSupport: PreferenceRequest<Boolean>(
+        key = PrefKeys.RtlSupport,
+        defaultValue = false
+    )
+
     object ShowDoubleTapMessage: PreferenceRequest<Boolean>(
         key = PrefKeys.ShowDoubleTapMessage,
         defaultValue = true

app/src/main/java/com/farmerbb/notepad/ui/components/IconButtons.kt

@@ -19,6 +19,7 @@ import androidx.compose.material.Icon
 import androidx.compose.material.IconButton
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ArrowBack
+import androidx.compose.material.icons.filled.ArrowForward
 import androidx.compose.material.icons.filled.Delete
 import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.MoreVert
@@ -28,14 +29,21 @@ import androidx.compose.material.icons.filled.SdCard
 import androidx.compose.material.icons.filled.SelectAll
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalLayoutDirection
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.LayoutDirection
 import com.farmerbb.notepad.R
 
 @Composable
 fun BackButton(onClick: () -> Unit = {}) {
+    val imageVector = when(LocalLayoutDirection.current) {
+        LayoutDirection.Rtl -> Icons.Filled.ArrowForward
+        else -> Icons.Filled.ArrowBack
+    }
+
     IconButton(onClick = onClick) {
         Icon(
-            imageVector = Icons.Filled.ArrowBack,
+            imageVector = imageVector,
             contentDescription = null,
             tint = Color.White
         )

app/src/main/java/com/farmerbb/notepad/ui/components/NotepadTheme.kt

@@ -0,0 +1,40 @@
+/* Copyright 2022 Braden Farmer
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.farmerbb.notepad.ui.components
+
+import androidx.compose.material.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.unit.LayoutDirection
+
+@Composable
+fun NotepadTheme(
+    rtlSupport: Boolean,
+    content: @Composable () -> Unit
+) {
+    val layoutDirection = when(rtlSupport) {
+        true -> LayoutDirection.Rtl
+        false -> LayoutDirection.Ltr
+    }
+
+    MaterialTheme {
+        CompositionLocalProvider(
+            LocalLayoutDirection provides layoutDirection,
+            content = content
+        )
+    }
+}

app/src/main/java/com/farmerbb/notepad/ui/routes/AppSettings.kt

@@ -117,6 +117,11 @@ fun NotepadPreferenceScreen(
                 title = stringResource(id = R.string.pref_title_markdown),
                 singleLineTitle = false,
                 enabled = !directEdit
+            ),
+            SwitchPreference(
+                request = Prefs.RtlSupport,
+                title = stringResource(id = R.string.rtl_support),
+                singleLineTitle = false
             )
         ),
         contentPadding = PaddingValues(8.dp),

app/src/main/java/com/farmerbb/notepad/ui/routes/NotepadComposeApp.kt

@@ -37,7 +37,6 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.material.Divider
 import androidx.compose.material.FloatingActionButton
 import androidx.compose.material.Icon
-import androidx.compose.material.MaterialTheme
 import androidx.compose.material.Scaffold
 import androidx.compose.material.TopAppBar
 import androidx.compose.material.icons.Icons
@@ -84,6 +83,7 @@ import com.farmerbb.notepad.ui.components.FirstViewDialog
 import com.farmerbb.notepad.ui.components.MultiSelectButton
 import com.farmerbb.notepad.ui.components.NoteListMenu
 import com.farmerbb.notepad.ui.components.NoteViewEditMenu
+import com.farmerbb.notepad.ui.components.NotepadTheme
 import com.farmerbb.notepad.ui.components.SaveButton
 import com.farmerbb.notepad.ui.components.SaveDialog
 import com.farmerbb.notepad.ui.components.SelectAllButton
@@ -104,6 +104,7 @@ fun NotepadComposeAppRoute() {
     val configuration = LocalConfiguration.current
 
     val isLightTheme by vm.prefs.isLightTheme.collectAsState()
+    val rtlSupport by vm.prefs.rtlSupport.collectAsState()
     val draftId by vm.savedDraftId.collectAsState()
 
     LaunchedEffect(Unit) {
@@ -112,7 +113,7 @@ fun NotepadComposeAppRoute() {
 
     if (draftId == null) return
 
-    MaterialTheme {
+    NotepadTheme(rtlSupport) {
         NotepadComposeApp(
             vm = vm,
             isMultiPane = configuration.screenWidthDp >= 600,

app/src/main/java/com/farmerbb/notepad/ui/routes/StandaloneEditor.kt

@@ -1,7 +1,6 @@
 package com.farmerbb.notepad.ui.routes
 
 import androidx.activity.compose.BackHandler
-import androidx.compose.material.MaterialTheme
 import androidx.compose.material.Scaffold
 import androidx.compose.material.TopAppBar
 import androidx.compose.runtime.Composable
@@ -20,6 +19,7 @@ import com.farmerbb.notepad.ui.components.AppBarText
 import com.farmerbb.notepad.ui.components.BackButton
 import com.farmerbb.notepad.ui.components.DeleteButton
 import com.farmerbb.notepad.ui.components.DeleteDialog
+import com.farmerbb.notepad.ui.components.NotepadTheme
 import com.farmerbb.notepad.ui.components.SaveButton
 import com.farmerbb.notepad.ui.components.SaveDialog
 import com.farmerbb.notepad.ui.components.StandaloneEditorMenu
@@ -36,8 +36,9 @@ fun StandaloneEditorRoute(
     val vm: NotepadViewModel = getViewModel()
     val systemUiController = rememberSystemUiController()
     val isLightTheme by vm.prefs.isLightTheme.collectAsState()
+    val rtlSupport by vm.prefs.rtlSupport.collectAsState()
 
-    MaterialTheme {
+    NotepadTheme(rtlSupport) {
         StandaloneEditor(
             vm = vm,
             initialText = initialText,

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

@@ -56,4 +56,5 @@
     <string name="no_notes_to_export">لم تُحَدَّد ملاحظاتٌ لتصديرها</string>
     <string name="no_notes_to_delete">لم تُحَدَّد ملاحظاتٌ لحذفها</string>
     <string name="check_for_updates">تحقّق من التحديثات</string>
+    <string name="rtl_support">Right-to-left support</string>
 </resources>

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

@@ -74,6 +74,7 @@
     <string name="no_notes_to_export">এক্সপোর্ট করার জন্য কোন নোট নির্বাচন করা হয়নি</string>
     <string name="no_notes_to_delete">মুছে ফেলার জন্য কোন নোট নির্বাচন করা হয়নি</string>
     <string name="check_for_updates">হালনাগাদ আছে কি না দেখুন</string>
+    <string name="rtl_support">Right-to-left support</string>
 
     <string-array name="sort_by_list">
         <item>তারিখ (একদম নতুন)</item>