/**
 * 二维码生成工具类
 */
public class QRCodeUtil {
 /**
  * 生成二维码Bitmap
  *
  * @param content 内容
  * @param widthPix 图片宽度
  * @param heightPix 图片高度
  * @param logoBm 二维码中心的Logo图标（可以为null）
  * @param filePath 用于存储二维码图片的文件路径
  * @return 生成二维码及保存文件是否成功
  */
 public static boolean createQRImage(String content, int widthPix, int heightPix, Bitmap logoBm, String filePath) {
  try {
   if (content == null || "".equals(content)) {
    return false;
   }
   //配置参数
   Map<encodehinttype, object=""> hints = new HashMap<>();
   hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
   //容错级别
   hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
   //设置空白边距的宽度
//   hints.put(EncodeHintType.MARGIN, 2); //default is 4
   // 图像数据转换，使用了矩阵转换
   BitMatrix bitMatrix = new QRCodeWriter().encode(content, BarcodeFormat.QR_CODE, widthPix, heightPix, hints);
   int[] pixels = new int[widthPix * heightPix];
   // 下面这里按照二维码的算法，逐个生成二维码的图片，
   // 两个for循环是图片横列扫描的结果
   for (int y = 0; y < heightPix; y++) {
    for (int x = 0; x < widthPix; x++) {
     if (bitMatrix.get(x, y)) {
      pixels[y * widthPix + x] = 0xff000000;
     } else {
      pixels[y * widthPix + x] = 0xffffffff;
     }
    }
   }
   // 生成二维码图片的格式，使用ARGB_8888
   Bitmap bitmap = Bitmap.createBitmap(widthPix, heightPix, Bitmap.Config.ARGB_8888);
   bitmap.setPixels(pixels, 0, widthPix, 0, 0, widthPix, heightPix);
   if (logoBm != null) {
    bitmap = addLogo(bitmap, logoBm);
   }
   //必须使用compress方法将bitmap保存到文件中再进行读取。直接返回的bitmap是没有任何压缩的，内存消耗巨大！
   return bitmap != null && bitmap.compress(Bitmap.CompressFormat.JPEG, 100, new FileOutputStream(filePath));
  } catch (WriterException | IOException e) {
   e.printStackTrace();
  }
  return false;
 }
 /**
  * 在二维码中间添加Logo图案
  */
 private static Bitmap addLogo(Bitmap src, Bitmap logo) {
  if (src == null) {
   return null;
  }
  if (logo == null) {
   return src;
  }
  //获取图片的宽高
  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;
  }
  //logo大小为二维码整体大小的1/5
  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 / 2, srcHeight / 2);
   canvas.drawBitmap(logo, (srcWidth - logoWidth) / 2, (srcHeight - logoHeight) / 2, null);
   canvas.save(Canvas.ALL_SAVE_FLAG);
   canvas.restore();
  } catch (Exception e) {
   bitmap = null;
   e.getStackTrace();
  }
  return bitmap;
 }
}</encodehinttype,>

/**
 * 二维码生成
 */
public class MainActivity extends ActionBarActivity {
 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
 
  //内容
  final EditText contentET = (EditText) findViewById(R.id.create_qr_content);
  //显示二维码图片
  final ImageView imageView = (ImageView) findViewById(R.id.create_qr_iv);
  //是否添加Logo
  final CheckBox addLogoCB = (CheckBox) findViewById(R.id.create_qr_addLogo);
  Button createQrBtn = (Button) findViewById(R.id.create_qr_btn);
 
  createQrBtn.setOnClickListener(new View.OnClickListener() {
 
   @Override
   public void onClick(View v) {
    final String filePath = getFileRoot(MainActivity.this) + File.separator
      + "qr_" + System.currentTimeMillis() + ".jpg";
 
    //二维码图片较大时，生成图片、保存文件的时间可能较长，因此放在新线程中
    new Thread(new Runnable() {
     @Override
     public void run() {
      boolean success = QRCodeUtil.createQRImage(contentET.getText().toString().trim(), 800, 800,
        addLogoCB.isChecked() ? BitmapFactory.decodeResource(getResources(), R.mipmap.qr_logo) : null,
        filePath);
 
      if (success) {
       runOnUiThread(new Runnable() {
        @Override
        public void run() {
         imageView.setImageBitmap(BitmapFactory.decodeFile(filePath));
        }
       });
      }
     }
    }).start();
 
   }
  });
 }
 
 //文件存储根目录
 private String getFileRoot(Context context) {
  if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
   File external = context.getExternalFilesDir(null);
   if (external != null) {
    return external.getAbsolutePath();
   }
  }
  return context.getFilesDir().getAbsolutePath();
 }
}

context.getExternalFilesDir(null)

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

@Override 
public Bitmap generateBitmap(String content, int width, int height) { 
 QRCodeWriter qrCodeWriter = new QRCodeWriter(); 
 Map<EncodeHintType, String> hints = new HashMap<>(); 
 hints.put(EncodeHintType.CHARACTER_SET, "utf-8");//默认 
  hints.put(EncodeHintType.MARGIN, "1");//无白色边框 
 try { 
  BitMatrix encode = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, width, height, hints); 
  int[] pixels = new int[width * height]; 
  for (int i = 0; i < height; i++) { 
   for (int j = 0; j < width; j++) { 
    if (encode.get(j, i)) { 
     pixels[i * width + j] = 0x00000000; 
    } else { 
     pixels[i * width + j] = 0xffffffff; 
    } 
   } 
  } 
  return Bitmap.createBitmap(pixels, 0, width, width, height, Bitmap.Config.RGB_565); 
 } catch (WriterException e) { 
  e.printStackTrace(); 
 } 
 return null; 
} 
@Override 
public Bitmap addLogo(Bitmap qrBitmap, Bitmap logoBitmap) { 
 int qrBitmapWidth = qrBitmap.getWidth(); 
 int qrBitmapHeight = qrBitmap.getHeight(); 
 int logoBitmapWidth = logoBitmap.getWidth(); 
 int logoBitmapHeight = logoBitmap.getHeight(); 
 Bitmap blankBitmap = Bitmap.createBitmap(qrBitmapWidth, qrBitmapHeight, Bitmap.Config.ARGB_8888); 
 Canvas canvas = new Canvas(blankBitmap); 
 canvas.drawBitmap(qrBitmap, 0, 0, null); 
 canvas.save(Canvas.ALL_SAVE_FLAG); 
 float scaleSize = 1.0f; 
 while ((logoBitmapWidth / scaleSize) > (qrBitmapWidth / 3.5) || (logoBitmapHeight / scaleSize) > (qrBitmapHeight / 3.5)) { 
  scaleSize *= 2; 
 } 
 float sx = 1.0f / scaleSize; 
 canvas.scale(sx, sx, qrBitmapWidth / 2, qrBitmapHeight / 2); 
 canvas.drawBitmap(logoBitmap, (qrBitmapWidth - logoBitmapWidth) / 2, (qrBitmapHeight - logoBitmapHeight) / 2, null); 
 canvas.restore(); 
 return blankBitmap; 
}