How to write exif data to image in Android?

You need first to copy the exif files located here google exif to your project, then use the following code :

    ExifInterface exif = new ExifInterface();    exif.readExif(exifVar.getAbsolutePath());    exif.setTagValue(ExifInterface.TAG_USER_COMMENT, mString);    exif.forceRewriteExif(exifVar.getAbsolutePath())); 

ExifInterface used here is the new one you've just added.

You're using exifVar.toString(). This returns just the filename, not the path to the image. As your app is probably not in the folder with pictures, you should use exifVar.getAbsolutePath().

If you're not taking the picture at the same time you're running the program, the Path won't be right. Use this code instead:

File[] files = directory.listFiles();if(files.length==0) {    // No images available    return;}File newestFile = files[files.length-1];File exifVar =  new File(directory.getPath() + File.separator + newestFile.getName());

Off-Topic:

According to your huge import list:

import android.content.*;

imports

android.content.Context,android.content.DialogInterface andandroid.content.Intent

That makes your code quite a bit shorter. Just saying

Make sure you set the write to sd permission (both static and dynamic),Also for Android 10, you need to set this:android:requestLegacyExternalStorage="true"

to the manifest application