public class QRUtil {
    /**
     * 生成二维码
     * @param content 二维码内容
     * @param width 宽度
     * @param height 高度
     * @param logo 图标
     * @return Bitmap
     */
    public static Bitmap createQRImage(String content, int width, int height, Bitmap logo) {
        try {
            if (content == null || "".equals(content)) {
                return null;
            }
            Map<EncodeHintType, Object> hints = new HashMap<>();
            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            hints.put(EncodeHintType.MARGIN, 1);

            BitMatrix bitMatrix = null;
            try {
                bitMatrix = new QRCodeWriter().encode(content, BarcodeFormat.QR_CODE, width, height, hints);
            } catch (WriterException e) {
                e.printStackTrace();
            }
            int[] pixels = new int[width * height];
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    if (bitMatrix.get(x, y)) {
                        pixels[y * width + x] = 0xff000000;
                    } else {
                        pixels[y * width + x] = 0xffffffff;
                    }
                }
            }

            Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
            bitmap.setPixels(pixels, 0, width, 0, 0, width, height);

            if (logo != null) {
                bitmap = addLogo(bitmap, logo);
            }
            return bitmap;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 向二维码中心添加图标
     * @param src 原(二维码)图
     * @param logo 图标 Bitmap
     * @return Bitmap
     */
    private static Bitmap addLogo(Bitmap src, Bitmap logo) {
        if (src == null) {
            return null;
        }

        if (logo == null) {
            return src;
        }

        int srcWidth = src.getWidth();
        int srcHeight = src.getHeight();
        int logoWidth = logo.getWidth();
        int logoHeight = logo.getHeight();

        if (srcWidth == 0 || srcHeight == 0) {
            return null;
        }

        if (logoWidth == 0 || logoHeight == 0) {
            return src;
        }

        float scaleFactor = srcWidth * 1.0f / 5 / logoWidth;
        Bitmap bitmap = Bitmap.createBitmap(srcWidth, srcHeight, Bitmap.Config.ARGB_8888);
        try {
            Canvas canvas = new Canvas(bitmap);
            canvas.drawBitmap(src, 0, 0, null);
            canvas.scale(scaleFactor, scaleFactor, srcWidth / (float) 2, srcHeight / (float) 2);
            canvas.drawBitmap(logo, (srcWidth - logoWidth) / (float) 2, (srcHeight - logoHeight) / (float) 2, null);
            canvas.save();
            canvas.restore();
        } catch (Exception e) {
            bitmap = null;
            e.getStackTrace();
        }

        return bitmap;
    }
}

public class MainActivity extends AppCompatActivity implements View.OnClickListener, TextWatcher {

    private static final int REQUEST_EXTERNAL_STORAGE = 1;
    private static String[] PERMISSIONS_STORAGE = {
            "android.permission.READ_EXTERNAL_STORAGE",
            "android.permission.WRITE_EXTERNAL_STORAGE"
    };

    private ImageView iv_qr;
    private EditText et_content;

    private int PICK_RESULT_CODE = 1;

    private Bitmap logoBM = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        try {
            int permission = ActivityCompat.checkSelfPermission(MainActivity.this, "android.permission.WRITE_EXTERNAL_STORAGE");
            if (permission != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        iv_qr = findViewById(R.id.iv_qr);
        et_content = findViewById(R.id.et_content);
        et_content.addTextChangedListener(this);

        findViewById(R.id.btn_pick_icon).setOnClickListener(this);
    }

    public void enableChanges() {
        int devWid = getResources().getDisplayMetrics().widthPixels;
        iv_qr.setImageBitmap(QRUtil.createQRImage(et_content.getText().toString(), devWid, devWid, logoBM));
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_pick_icon:
                Intent PickIntent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                startActivityForResult(PickIntent, PICK_RESULT_CODE);
                break;
        }
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        enableChanges();
    }

    @Override
    public void afterTextChanged(Editable s) {

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PICK_RESULT_CODE && resultCode == RESULT_OK && null != data) {
            String imagePath = null;
            Uri uri = data.getData();
            String[] project = {MediaStore.Images.Media.DATA};
            Cursor cursor = getContentResolver().query(uri, project, null, null, null);
            assert cursor != null;
            if (cursor.moveToFirst()) {
                ;
                int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
                imagePath = cursor.getString(column_index);
            }
            cursor.close();
            logoBM = BitmapFactory.decodeFile(imagePath);
            enableChanges();
        }
    }
}