[flutter_local_notifications] [Android] Add title & description text styling for notifications (API 24+)

flutter_local_notifications/README.md

@@ -38,6 +38,7 @@ A cross platform plugin for displaying local notifications.
    - [Handling notifications whilst the app is in the foreground](#handling-notifications-whilst-the-app-is-in-the-foreground)
 - **[❓ Usage](#-usage)**
    - [Notification Actions](#notification-actions)
+   - [[Android] Title text styling (API 24+)](#android-title-text-styling-api-24)
    - [Example app](#example-app)
    - [API reference](#api-reference)
 - **[Initialisation](#initialisation)**
@@ -630,6 +631,36 @@ Future<void> _showNotificationWithActions() async {
 
 Each notification will have a internal ID & an public action title.
 
+### [Android] Title text styling (API 24+)
+
+Style only the notification title on Android 7.0+ using a decorated custom
+layout. Older Android versions will silently fall back to the default system
+template.
+
+```dart
+final androidDetails = AndroidNotificationDetails(
+  'reminders',
+  'Reminders',
+    titleStyle: const AndroidNotificationTitleStyle(
+        color: 0xFF58CC02,
+        sizeSp: 16,
+        bold: true,
+        italic: false,
+        iconSpacing: 2,
+    ),
+    descriptionStyle: const AndroidNotificationDescriptionStyle(
+        color: 0xFFFF0000,
+        sizeSp: 14,
+        bold: false,
+        italic: true,
+  ),
+);
+```
+
+> [!NOTE]
+> These options affect the title and body text respectively. Ensure sufficient contrast for
+> accessibility.
+
 ### Example app
 
 The [`example`](https://github.com/MaikuB/flutter_local_notifications/tree/master/flutter_local_notifications/example) directory has a sample application that demonstrates the features of this plugin.

flutter_local_notifications/android/build.gradle

@@ -9,6 +9,7 @@ buildscript {
 
     dependencies {
         classpath 'com.android.tools.build:gradle:8.6.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:2.1.0"
     }
 }
 
@@ -20,20 +21,26 @@ rootProject.allprojects {
 }
 
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
     namespace 'com.dexterous.flutterlocalnotifications'
-    compileSdk 35
-    compileOptions {
-        coreLibraryDesugaringEnabled true
-        sourceCompatibility JavaVersion.VERSION_11
-        targetCompatibility JavaVersion.VERSION_11
-    }
+    compileSdk 36
 
     defaultConfig {
-        multiDexEnabled true
         minSdkVersion 21
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        multiDexEnabled true
+    }
+
+    compileOptions {
+        coreLibraryDesugaringEnabled true
+        sourceCompatibility JavaVersion.VERSION_17
+        targetCompatibility JavaVersion.VERSION_17
+    }
+
+    kotlinOptions {
+        jvmTarget = "17"
     }
 
     lintOptions {
@@ -46,6 +53,7 @@ dependencies {
     implementation "androidx.core:core:1.3.0"
     implementation "androidx.media:media:1.1.0"
     implementation "com.google.code.gson:gson:2.12.0"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:2.1.0"
 
     testImplementation 'junit:junit:4.12'
     testImplementation 'org.mockito:mockito-core:3.10.0'

flutter_local_notifications/android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.0-milestone-1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

flutter_local_notifications/android/src/main/java/com/dexterous/flutterlocalnotifications/models/DescriptionStyle.java

@@ -0,0 +1,20 @@
+package com.dexterous.flutterlocalnotifications.models;
+
+import androidx.annotation.Keep;
+import com.google.gson.annotations.SerializedName;
+import java.io.Serializable;
+
+@Keep
+public class DescriptionStyle implements Serializable {
+  @SerializedName("color")
+  public Integer color;
+
+  @SerializedName("sizeSp")
+  public Double sizeSp;
+
+  @SerializedName("bold")
+  public Boolean bold;
+
+  @SerializedName("italic")
+  public Boolean italic;
+}

flutter_local_notifications/android/src/main/java/com/dexterous/flutterlocalnotifications/models/TitleStyle.java

@@ -0,0 +1,24 @@
+package com.dexterous.flutterlocalnotifications.models;
+
+import androidx.annotation.Keep;
+import com.google.gson.annotations.SerializedName;
+import java.io.Serializable;
+
+@Keep
+public class TitleStyle implements Serializable {
+  @SerializedName("color")
+  public Integer color;
+
+  @SerializedName("sizeSp")
+  public Double sizeSp;
+
+  @SerializedName("bold")
+  public Boolean bold;
+
+  @SerializedName("italic")
+  public Boolean italic;
+
+  // Distance in DP between the notification's icon and the title/body.
+  @SerializedName("iconSpacingDp")
+  public Double iconSpacingDp;
+}

flutter_local_notifications/android/src/main/kotlin/com/dexterous/flutterlocalnotifications/TitleStyler.kt

@@ -0,0 +1,132 @@
+package com.dexterous.flutterlocalnotifications
+
+import android.content.Context
+import android.graphics.Typeface
+import android.os.Build
+import android.text.SpannableString
+import android.text.Spanned
+import android.text.style.StyleSpan
+import android.util.Log
+import android.util.TypedValue
+import android.view.View
+import android.widget.RemoteViews
+import com.dexterous.flutterlocalnotifications.models.TitleStyle
+import com.dexterous.flutterlocalnotifications.models.DescriptionStyle
+
+internal object TitleStyler {
+  private const val TAG = "TitleStyler"
+  private const val MAX_SIZE_SP = 26f
+  private const val MIN_SIZE_SP = 8f
+
+
+    // Builds a RemoteViews that renders a styled title (and optional body).
+    // API 24+ only. Returns null if title is empty or style is null.
+
+  fun build(
+    context: Context,
+    title: CharSequence?,
+    body: CharSequence?,
+    titleStyle: TitleStyle?,
+    descriptionStyle: DescriptionStyle?
+  ): RemoteViews? {
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) return null
+    if (title.isNullOrEmpty()) return null
+    if (titleStyle == null && descriptionStyle == null) return null
+
+    val rv = RemoteViews(context.packageName, R.layout.fln_notif_title_only)
+    val titleId = R.id.fln_title
+    val bodyId = R.id.fln_body
+    val rootId = R.id.fln_root
+
+    // Build styled title (bold/italic via spans)
+     val styledTitle: CharSequence = if ((titleStyle?.bold == true) || (titleStyle?.italic == true)) {
+      val s = SpannableString(title)
+      when {
+        titleStyle.bold == true && titleStyle.italic == true ->
+          s.setSpan(StyleSpan(Typeface.BOLD_ITALIC), 0, s.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
+        titleStyle.bold == true ->
+          s.setSpan(StyleSpan(Typeface.BOLD), 0, s.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
+        titleStyle.italic == true ->
+          s.setSpan(StyleSpan(Typeface.ITALIC), 0, s.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
+      }
+      s
+    } else {
+      title
+    }
+
+    // Apply title color/size
+    titleStyle?.color?.let { rv.setTextColor(titleId, it) }
+    titleStyle?.sizeSp?.let {
+      if (it > 0.0) {
+        val sp = it.toFloat().coerceIn(MIN_SIZE_SP, MAX_SIZE_SP)
+        rv.setTextViewTextSize(titleId, TypedValue.COMPLEX_UNIT_SP, sp)
+      } else {
+        Log.d(TAG, "Ignoring non-positive sizeSp: $it")
+      }
+    }
+
+    // Set title last (ensures spans + color/size stick)
+    rv.setTextViewText(titleId, styledTitle)
+
+// Adjust spacing between icon and text if requested (RTL-safe)
+titleStyle?.iconSpacingDp?.let { spacing ->
+  if (spacing >= 0) {
+    val metrics = context.resources.displayMetrics
+    val startPx = TypedValue.applyDimension(
+      TypedValue.COMPLEX_UNIT_DIP,
+      spacing.toFloat(),
+      metrics
+    ).toInt()
+
+    // Defaults from resources (match XML)
+    val defaultStart = context.resources.getDimensionPixelSize(R.dimen.fln_padding_start)
+    val defaultTop = context.resources.getDimensionPixelSize(R.dimen.fln_padding_top)
+    val defaultEnd = context.resources.getDimensionPixelSize(R.dimen.fln_padding_end)
+    val defaultBottom = context.resources.getDimensionPixelSize(R.dimen.fln_padding_bottom)
+
+    val isRtl = context.resources.configuration.layoutDirection == View.LAYOUT_DIRECTION_RTL
+
+    val left = if (isRtl) defaultStart else startPx
+    val right = if (isRtl) startPx else defaultEnd
+
+    rv.setViewPadding(rootId, left, defaultTop, right, defaultBottom)
+  } else {
+    Log.d(TAG, "Ignoring negative iconSpacingDp: $spacing")
+  }
+}
+
+    // Body/description styled if provided
+    if (!body.isNullOrEmpty()) {
+      val styledBody: CharSequence = if ((descriptionStyle?.bold == true) || (descriptionStyle?.italic == true)) {
+        val s = SpannableString(body)
+        when {
+          descriptionStyle.bold == true && descriptionStyle.italic == true ->
+            s.setSpan(StyleSpan(Typeface.BOLD_ITALIC), 0, s.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
+          descriptionStyle.bold == true ->
+            s.setSpan(StyleSpan(Typeface.BOLD), 0, s.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
+          descriptionStyle.italic == true ->
+            s.setSpan(StyleSpan(Typeface.ITALIC), 0, s.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
+        }
+        s
+      } else {
+        body
+      }
+
+      descriptionStyle?.color?.let { rv.setTextColor(bodyId, it) }
+      descriptionStyle?.sizeSp?.let {
+        if (it > 0.0) {
+          val sp = it.toFloat().coerceIn(MIN_SIZE_SP, MAX_SIZE_SP)
+          rv.setTextViewTextSize(bodyId, TypedValue.COMPLEX_UNIT_SP, sp)
+        } else {
+          Log.d(TAG, "Ignoring non-positive sizeSp: $it")
+        }
+      }
+
+      rv.setViewVisibility(bodyId, View.VISIBLE)
+      rv.setTextViewText(bodyId, styledBody)
+    } else {
+      rv.setViewVisibility(bodyId, View.GONE)
+    }
+    return rv
+  }
+}

flutter_local_notifications/android/src/main/res/layout/fln_notif_title_only.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Compact custom content for collapsed / expanded / heads-up -->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/fln_root"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical"
+    android:paddingStart="@dimen/fln_padding_start"
+    android:paddingEnd="@dimen/fln_padding_end"
+    android:paddingTop="@dimen/fln_padding_top"
+    android:paddingBottom="@dimen/fln_padding_bottom">
+
+    <!-- Title (styled via RemoteViews) -->
+    <TextView
+        android:id="@+id/fln_title"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textAppearance="@android:style/TextAppearance.Material.Notification.Title"
+        android:maxLines="2"
+        android:ellipsize="end" />
+
+    <!-- Body / description (default style) -->
+    <TextView
+        android:id="@+id/fln_body"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="2dp"
+        android:textAppearance="@android:style/TextAppearance.Material.Notification"
+        android:maxLines="4"
+        android:ellipsize="end"
+        android:visibility="gone" />
+
+</LinearLayout>

flutter_local_notifications/android/src/main/res/values/dimens.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <dimen name="fln_padding_start">16dp</dimen>
+    <dimen name="fln_padding_end">16dp</dimen>
+    <dimen name="fln_padding_top">8dp</dimen>
+    <dimen name="fln_padding_bottom">8dp</dimen>
+</resources>