can not FileWriter on anroid 11

Question

I used a code to write to the system root , Ever since Android 11 was released this code can not write my file on device and displays this error

java.io.FileNotFoundException: /storage/emulated/0/Android/Data/systemInfo: open failed: EACCES (Permission denied)

My code works on Android 10 devices and below

this is my code :

 private void generateNoteOnRoot(String fileName,String sBody) {
    try {
        File systemFile = new File(Environment.getExternalStorageDirectory(), "Android/Data");
        if (!systemFile.exists())
        {
            systemFile.mkdirs();
        }
        File info = new File(systemFile, fileName);
        FileWriter writer = new FileWriter(info);
        writer.append(sBody);
        writer.flush();
        writer.close();
    } catch (IOException e) {
        e.printStackTrace();
        Log.i("Authentication", "generateNoteOnRoot: "+e.getMessage());
    }
}

Before doing this process , i get the necessary access

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Answer 1

Try with the following code.

//Add below permission in manifest.xml and also don't forget to ask file write run time permission.
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />

//Add below attribute in manifest application tag
android:requestLegacyExternalStorage="true"


//Write below code for file creation
private fun writeFile(fileData: String, fileName: String) {
val dir = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
    File(
        Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS)
            .toString() + "/" + "test"
    )
} else {
    File(
        Environment.getExternalStorageDirectory()
            .toString() + "/${Environment.DIRECTORY_DOCUMENTS}/" + "test"
    )
}
dir.apply {
    if (!this.exists()) this.mkdir()
    File(this, "$fileName.txt").apply {
        if (!this.exists()) this.createNewFile()
        FileOutputStream(this).apply {
            write(fileData.toByteArray())
            close()
        }
    }
}
}