我试图在内部存储器中保存文件，但没有获得成功。我遵循this文件。我也试图在内部存储器中保存录制的音频文件。当我搜索保存文件在设备中，所以没有到达那里。下面的代码清单我有使用。

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
package="com.example.untitled1">

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<!--<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" tools:ignore="ScopedStorage" />-->
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAG" />
<uses-permission android:name="android.permission.ACCESS_MEDIA_LOCATION"/>

<application
    android:label="untitled1"
    android:name="${applicationName}"
    android:icon="@mipmap/ic_launcher">
    <activity
        android:name=".MainActivity"
        android:exported="true"
        android:launchMode="singleTop"
        android:theme="@style/LaunchTheme"
        android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
        android:hardwareAccelerated="true"
        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"
          />
        <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 -->
    <meta-data
        android:name="flutterEmbedding"
        android:value="2" />
</application>

请帮助我解决我的代码有什么问题。