生成和解析二维码(zxing)

首先在gradle中引入zxing：

compile 'com.google.zxing:core:3.1.0'

然后是工具类：

/**
* 解析二维码的工具类<br/>
* 1.必须在项目中引入zxing
* 2.支持生成二维码
* 3.解析图片中的二维码
* 4.把二维码保存到本地
* Created by hsji on 2016/1/14.
*/
public class QRCodeUtils
{
private static final String TAG = QRCodeUtils.class.getSimpleName();
public static final String CHARSET_UTF_8 = "UTF-8";
public static final String CHARSET_GBK = "GBK";

/**
* 默认生成方法
*
* @param context
* @param content
* @return
*/
public static final Bitmap encodeAsBitmap(Context context, String content)
{
//默认二维码的宽度为屏幕宽度的一半
int size = Math.min(context.getResources().getDisplayMetrics().widthPixels, context.getResources().getDisplayMetrics().heightPixels) / 2;
return encodeAsBitmap(content, CHARSET_UTF_8, size);
}

/**
* 生成二维码
*
* @param content    字符串内容
* @param encodeType 编码格式
* @param size       二维码的尺寸
* @return
*/
public static final Bitmap encodeAsBitmap(String content, String encodeType, int size)
{
if (TextUtils.isEmpty(content))
{
return null;
}
Map<EncodeHintType, Object> hints = null;
hints = new EnumMap<>(EncodeHintType.class);
//指定编码格式
hints.put(EncodeHintType.CHARACTER_SET, encodeType);
//指定纠错等级 L:7%  M:15%  Q:25%  H:30%
hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
BitMatrix result;
try
{
result = new MultiFormatWriter().encode(content, BarcodeFormat.QR_CODE, size, size, hints);
} catch (IllegalArgumentException e)
{
e.printStackTrace();
return null;
} catch (WriterException e)
{
e.printStackTrace();
return null;
}

int[] pixels = new int[size * size];
for (int y = 0; y < size; y++)
{
int offset = y * size;
for (int x = 0; x < size; x++)
{
pixels[offset + x] = result.get(x, y) ? 0x000000 : 0xffffff;
}
}
//没有透明度  节省内存
return Bitmap.createBitmap(pixels, size, size, Bitmap.Config.RGB_565);
}

/**
* 解析二维码
*
* @param path
* @return
*/
public static String decode(String path)
{
if (TextUtils.isEmpty(path))
{
return null;
}
Hashtable<DecodeHintType, String> hints = new Hashtable<DecodeHintType, String>();
//设置编码格式
hints.put(DecodeHintType.CHARACTER_SET, CHARSET_UTF_8);
Bitmap src = BitmapFactory.decodeFile(path);
int[] pixels = new int[src.getWidth() * src.getHeight()];
src.getPixels(pixels, 0, src.getWidth(), 0, 0, src.getWidth(), src.getHeight());
RGBLuminanceSource source = new RGBLuminanceSource(src.getWidth(), src.getHeight(), pixels);
BinaryBitmap bb = new BinaryBitmap(new HybridBinarizer(source));
MultiFormatReader reader = new MultiFormatReader();
try
{
Result result = reader.decode(bb, hints);
return result.getText();
} catch (NotFoundException e)
{
e.printStackTrace();
}
return null;
}

/**
* 保存二维码到本地<br/>
* 直接保存二维码得到的是一张黑图（我也不知道什么原因）
*
* @param src
* @param path
* @return
*/
public static final boolean saveQRCode(Bitmap src, String path)
{
Bitmap target = Bitmap.createBitmap(src.getWidth(), src.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(target);
canvas.drawBitmap(src, 0.0f, 0.0f, new Paint());
BufferedOutputStream bos = null;
try
{
File file = new File(path);
if (file.exists())
{
file.delete();
}
bos = new BufferedOutputStream(new FileOutputStream(file));
target.compress(Bitmap.CompressFormat.PNG, 100, bos);
} catch (Exception e)
{
e.printStackTrace();
return false;
} finally
{
if (bos != null)
{
try
{
bos.flush();
bos.close();
} catch (Exception e)
{
e.printStackTrace();
}
}
if (target != null && !target.isRecycled())
{
target.recycle();
target = null;
}
}
return true;
}
}

最后是使用方法：

//生成二维码 显示在ImageView中
iv.setImageBitmap(QRCodeUtils.encodeAsBitmap(this, "https://www.baidu.com"));
//生成二维码并保存   之后在解析此二维码
if (FileUtils.isExternalFileSystemAccessible())
{
if (QRCodeUtils.saveQRCode(QRCodeUtils.encodeAsBitmap(this, "https://www.baidu.com"), Environment.getExternalStorageDirectory() + "/qrcode.png"))
{
Toast.makeText(this, "二维码保存成功！", Toast.LENGTH_SHORT).show();
mTextViewResult.setText(QRCodeUtils.decode(Environment.getExternalStorageDirectory() + "/qrcode.png"));
}
} else
{
Toast.makeText(this, "存储空间暂不可用！", Toast.LENGTH_SHORT).show();
}