<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.deneme_kaynak">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:name="${applicationName}"
        android:label="deneme_kaynak"
        android:icon="@mipmap/launcher_icon"
        android:requestLegacyExternalStorage="true"
        android:usesCleartextTraffic="true">

        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:exported="true"
            android:hardwareAccelerated="true"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:windowSoftInputMode="adjustResize">
            <!-- Specifies an Android theme to apply to this Activity as soon as
                 the Android process has started. This theme is visible to the user
                 while the Flutter UI initializes. After that, this theme continues
                 to determine the Window background behind the Flutter UI. -->
            <meta-data
                android:name="io.flutter.embedding.android.NormalTheme"
                android:resource="@style/NormalTheme" />
            <meta-data
                android:name="io.flutter.embedding.android.SplashScreenDrawable"
                android:resource="@drawable/launch_background"
                />
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!-- Don't delete the meta-data below.
             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED"></action>
            </intent-filter>
        </receiver>
        <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationReceiver" />

        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />
    </application>
</manifest>

ERROR

FAILURE: Build failed with an exception.

• What went wrong: Execution failed for task ':app:generateDebugBuildConfig'.

Error while evaluating property 'namespace' of task ':app:generateDebugBuildConfig' Failed to calculate the value of task ':app:generateDebugBuildConfig' property 'namespace'. > Failed to calculate the value of property 'namespace'. > org.xml.sax.SAXParseException; systemId: file:/Users/ddo/Desktop/projects/yedek/deneme_kaynak/android/app/src/main/AndroidManifest.xml; lineNumber: 27; columnNumber: 56; Attribute "exported" bound to namespace "http://schemas.android.com/apk/res/android" was already specified for element "activity".

• Try:

Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at

  EDIT

  You need to add for this element as well

  <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver" android:exported="true">
  

  its applicable to all services , activity and receiver declared in manifets file : https://cafonsomota.medium.com/android-12-dont-forget-to-set-android-exported-on-your-activities-services-and-receivers-3bee33f37beb

  This is how manifest file looks :

  <manifest xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      package="com.example.deneme_kaynak">
  
      <uses-permission android:name="android.permission.INTERNET" />
      <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
      <uses-permission android:name="android.permission.VIBRATE" />
      <uses-permission android:name="android.permission.WAKE_LOCK" />
      <uses-permission android:name="android.permission.CAMERA" />
      <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  
      <application
          android:name="${applicationName}"
          android:label="deneme_kaynak"
          android:icon="@mipmap/launcher_icon"
          android:requestLegacyExternalStorage="true"
          android:usesCleartextTraffic="true">
  
          <activity
              android:name=".MainActivity"
              android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
              android:exported="true"
              android:hardwareAccelerated="true"
              android:launchMode="singleTop"
              android:theme="@style/LaunchTheme"
              android:windowSoftInputMode="adjustResize">
              <!-- Specifies an Android theme to apply to this Activity as soon as
                   the Android process has started. This theme is visible to the user
                   while the Flutter UI initializes. After that, this theme continues
                   to determine the Window background behind the Flutter UI. -->
              <meta-data
                  android:name="io.flutter.embedding.android.NormalTheme"
                  android:resource="@style/NormalTheme" />
              <meta-data
                  android:name="io.flutter.embedding.android.SplashScreenDrawable"
                  android:resource="@drawable/launch_background"
                  />
              <intent-filter>
                  <action android:name="android.intent.action.MAIN" />
                  <category android:name="android.intent.category.LAUNCHER" />
              </intent-filter>
          </activity>
          <!-- Don't delete the meta-data below.
               This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
          <receiver android:name="com.dexterous.flutterlocalnotifications.ScheduledNotificationBootReceiver" android:exported="true">
              <intent-filter>
                  <action android:name="android.intent.action.BOOT_COMPLETED"></action>
              </intent-filter>
          </receiver>
        
  
          <meta-data
              android:name="flutterEmbedding"
              android:value="2" />
      </application>
  </manifest>