How to set ringtone in Android from my activity?

provide intent for ringtone selection.

final Uri currentTone= RingtoneManager.getActualDefaultRingtoneUri(MainActivity.this, RingtoneManager.TYPE_ALARM);
                Intent intent = new Intent(RingtoneManager.ACTION_RINGTONE_PICKER);
                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_TYPE, RingtoneManager.TYPE_RINGTONE);
                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_TITLE, "Select Tone");
                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_EXISTING_URI, currentTone);
                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_SHOW_SILENT, false);
                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_SHOW_DEFAULT, true);
                startActivityForResult(intent, 999);

then catch the result of selection in onActivityResult.

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(requestCode == 999 && resultCode == RESULT_OK){
            Uri uri = data.getParcelableExtra(RingtoneManager.EXTRA_RINGTONE_PICKED_URI);
            txtView.setText("From :" + uri.getPath());
            //Set selected ringtone here.
            RingtoneManager.setActualDefaultRingtoneUri(
                    this,
                    RingtoneManager.TYPE_RINGTONE,
                    uri
            );
        }
    }

I have try these code its help

  private void setRingtone(Context context, String path) {
    if (path == null) {
        return;
    }
    File file = new File(path);
    ContentValues contentValues = new ContentValues();
    contentValues.put(MediaStore.MediaColumns.DATA, file.getAbsolutePath());
    String filterName = path.substring(path.lastIndexOf("/") + 1);
    contentValues.put(MediaStore.MediaColumns.TITLE, filterName);
    contentValues.put(MediaStore.MediaColumns.MIME_TYPE, "audio/mp3");
    contentValues.put(MediaStore.MediaColumns.SIZE, file.length());
    contentValues.put(MediaStore.Audio.Media.IS_RINGTONE, true);
    Uri uri = MediaStore.Audio.Media.getContentUriForPath(path);
    Cursor cursor = context.getContentResolver().query(uri, null, MediaStore.MediaColumns.DATA + "=?", new String[]{path}, null);
    if (cursor != null && cursor.moveToFirst() && cursor.getCount() > 0) {
        String id = cursor.getString(0);
        contentValues.put(MediaStore.Audio.Media.IS_RINGTONE, true);
        context.getContentResolver().update(uri, contentValues, MediaStore.MediaColumns.DATA + "=?", new String[]{path});
        Uri newuri = ContentUris.withAppendedId(uri, Long.valueOf(id));
        try {
            RingtoneManager.setActualDefaultRingtoneUri(context, RingtoneManager.TYPE_RINGTONE, newuri);
            Toast.makeText(context, "Set as Ringtone Successfully.", Toast.LENGTH_SHORT).show();
        } catch (Throwable t) {
            t.printStackTrace();
        }
        cursor.close();
    }
}

If the accepted answer is not working then use this:

MediaStore.Audio.Media.INTERNAL_CONTENT_URI

instead of this:

MediaStore.Audio.Media.getContentUriForPath()

while inserting values into the database.

For example :

// Defining ringtone.....
ContentValues values = new ContentValues();
values.put(MediaStore.MediaColumns.DATA, file.getAbsolutePath());
values.put(MediaStore.MediaColumns.TITLE, "Sonify");
values.put(MediaStore.MediaColumns.MIME_TYPE, "audio/mp3");
values.put(MediaStore.Audio.Media.IS_RINGTONE, true);
values.put(MediaStore.Audio.Media.IS_NOTIFICATION,false);
values.put(MediaStore.Audio.Media.IS_ALARM, false);
values.put(MediaStore.Audio.Media.IS_MUSIC, false);

// Setting ringtone....
getContentResolver().delete(MediaStore.Audio.Media.INTERNAL_CONTENT_URI,MediaStore.Audio.Media.TITLE + " = \"Sonify\"",null); 
// To avoid duplicate inserts
Uri ringUri = getContentResolver().insert(MediaStore.Audio.Media.INTERNAL_CONTENT_URI, values);
RingtoneManager.setActualDefaultRingtoneUri(this, RingtoneManager.TYPE_ALARM, ringUri);

Dont forgot to add

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

Use this function to set Ringtone

private void setAsRingtone(String musicId) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (Settings.System.canWrite(this)) {
            Uri uri = ContentUris.withAppendedId(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, Long.parseLong(musicId));
            RingtoneManager.setActualDefaultRingtoneUri(
                    this,
                    RingtoneManager.TYPE_RINGTONE,
                    uri
            );
            Toast.makeText(this, "Ring set successfully", Toast.LENGTH_SHORT).show();
        } else {
            Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_WRITE_SETTINGS);
            intent.setData(Uri.parse("package:" + getPackageName()));
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        }
    }
}

Music Id can be obtained from Cursor. Hope you know it, or Check it here