MainActivity.java

package com.example.qrcode;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.journeyapps.barcodescanner.BarcodeEncoder;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        EditText editText=findViewById(R.id.edit_text);
        Button button=findViewById(R.id.button);
        ImageView imageview=findViewById(R.id.qr_code);


        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                MultiFormatWriter multiFormatWriter=new MultiFormatWriter();
                try{

                    BitMatrix bitMatrix=multiFormatWriter.encode(editText.getText().toString(), BarcodeFormat.QR_CODE,600,600);

                    BarcodeEncoder barcodeEncoder=new BarcodeEncoder();
                    Bitmap bitmap=barcodeEncoder.createBitmap(bitMatrix);

                    imageview.setImageBitmap(bitmap);
                }catch(WriterException e){
                    throw new RuntimeException(e);
                }
            }
        });
    }
}