用HTML5 可以实现二维码扫描识别的功能吗
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可以。实现基本步骤：
操作摄像头，获取图片。
技术要点：MediaStream、GetUserMedia、File api。
利用canvas使用相关算法分析图片识别图片得出结果。
技术要点：getImageData
* 涉及到的技术点浏览器们（包括移动端）支持各异，现阶段要开发并投产还不太现实
* 识别算法是一个难点，不过谢谢github，谢谢开源社区，@Shou Jiesong 的答案中有phonegap的插件地址，支持各种码。 参考技术A 搜索答案
用html5 可以实现二维码扫描识别的功能吗
sSAN2vkI | 浏览 5809 次 2015-03-22 13:06
2015-03-22 19:53最佳答案
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Barcode Example</title>
<script type="text/javascript" >
// 扩展API加载完毕后调用onPlusReady回调函数
document.addEventListener( "plusready", onPlusReady, false );
// 扩展API加载完毕，现在可以正常调用扩展API
function onPlusReady()
var e = document.getElementById("scan");
e.removeAttribute( "disabled" );
// 从图片中扫描
function scanImg()
plus.barcode.scan( '_www/barcode.png', function (type,result)
alert( "Scan success:("+type+")"+result );
, function (error)
alert( error.message );
);
</script>
<style type="text/css">
*
-webkit-user-select: none;
html,body
margin: 0px;
padding: 0px;
height: 100%;
</style>
</head>
<body >
<input id="scan" type='button' disabled="disabled" onclick='scanImg()' value='扫描图片'></input>
</body>
</html> 参考技术B 这个如果是手机的上的话，主要是依靠app自身的后台调用实现的，这个主要不是前端的技术。html5 只是网页的标签等展示。但具体的功能还是要依靠js或者是后端来实现。 参考技术C <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Barcode Example</title>
<script type="text/javascript" >
// 扩展API加载完毕后调用onPlusReady回调函数
document.addEventListener( "plusready", onPlusReady, false );
// 扩展API加载完毕，现在可以正常调用扩展API
function onPlusReady()
var e = document.getElementById("scan");
e.removeAttribute( "disabled" );
// 从图片中扫描
function scanImg()
plus.barcode.scan( '_www/barcode.png', function (type,result)
alert( "Scan success:("+type+")"+result );
, function (error)
alert( error.message );
);
</script>
<style type="text/css">
*
-webkit-user-select: none;
html,body
margin: 0px;
padding: 0px;
height: 100%;
</style>
</head>
<body >
<input id="scan" type='button' disabled="disabled" onclick='scanImg()' value='扫描图片'></input>
</body>
</html>
Android 基于google Zxing实现二维码的生成，识别和长按识别的效果
最近项目用到了二维码的生成与识别，之前没有接触这块，然后就上网搜了搜，发现有好多这方面的资源，特别是google Zxing对二维码的封装，实现的已经不错了，可以直接拿过来引用，下载了他们的源码后，只做了少少的改动，就是在Demo中增加了长按识别的功能，网上虽然也有长按识别的Demo，但好多下载下来却无法运行，然后总结了一下，加在了下面的Demo中。
如图所示，引用时直接把用红色圈起来的包放在你项目所对应的文件夹下，当然一些资源文件，比如string.xml里项目的引用你自己添加上就是 当然别忘了放架包
下面来介绍这个Demo的主类
public class BarCodeTestActivity extends Activity {
private TextView resultTextView;
private EditText qrStrEditText;
private ImageView qrImgImageView;
private String time;
private File file = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
resultTextView = (TextView) this.findViewById(R.id.tv_scan_result);
qrStrEditText = (EditText) this.findViewById(R.id.et_qr_string);
qrImgImageView = (ImageView) this.findViewById(R.id.iv_qr_image);
Button scanBarCodeButton = (Button) this.findViewById(R.id.btn_scan_barcode);
scanBarCodeButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//打开扫描界面扫描条形码或二维码
Intent openCameraIntent = new Intent(BarCodeTestActivity.this,CaptureActivity.class);
startActivityForResult(openCameraIntent, 0);
}
});
qrImgImageView.setOnLongClickListener(new OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
// 长按识别二维码
saveCurrentImage();
return true;
}
});
Button generateQRCodeButton = (Button) this.findViewById(R.id.btn_add_qrcode);
generateQRCodeButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
try {
String contentString = qrStrEditText.getText().toString();
if (!contentString.equals("")) {
//根据字符串生成二维码图片并显示在界面上，第二个参数为图片的大小（350*350）
Bitmap qrCodeBitmap = EncodingHandler.createQRCode(contentString, 350);
qrImgImageView.setImageBitmap(qrCodeBitmap);
}else {
//提示文本不能是空的
Toast.makeText(BarCodeTestActivity.this, "Text can not be empty", Toast.LENGTH_SHORT).show();
}
} catch (WriterException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
//这种方法状态栏是空白，显示不了状态栏的信息
private void saveCurrentImage()
{
//获取当前屏幕的大小
int width = getWindow().getDecorView().getRootView().getWidth();
int height = getWindow().getDecorView().getRootView().getHeight();
//生成相同大小的图片
Bitmap temBitmap = Bitmap.createBitmap( width, height, Bitmap.Config.ARGB_8888 );
//找到当前页面的根布局
View view = getWindow().getDecorView().getRootView();
//设置缓存
view.setDrawingCacheEnabled(true);
view.buildDrawingCache();
//从缓存中获取当前屏幕的图片,创建一个DrawingCache的拷贝，因为DrawingCache得到的位图在禁用后会被回收
temBitmap = view.getDrawingCache();
SimpleDateFormat df = new SimpleDateFormat("yyyymmddhhmmss");
time = df.format(new Date());
if(Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())){
file = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/screen",time + ".png");
if(!file.exists()){
file.getParentFile().mkdirs();
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
temBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.flush();
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
new Thread(new Runnable() {
@Override
public void run() {
String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/screen/" + time + ".png";
final Result result = parseQRcodeBitmap(path);
runOnUiThread(new Runnable() {
public void run() {
if(null!=result){
resultTextView.setText(result.toString());
}else{
Toast.makeText(BarCodeTestActivity.this, "无法识别", Toast.LENGTH_LONG).show();
}
}
});
}
}).start();
//禁用DrawingCahce否则会影响性能 ,而且不禁止会导致每次截图到保存的是缓存的位图
view.setDrawingCacheEnabled(false);
}
}
//解析二维码图片,返回结果封装在Result对象中
private com.google.zxing.Result parseQRcodeBitmap(String bitmapPath){
//解析转换类型UTF-8
Hashtable<DecodeHintType, String> hints = new Hashtable<DecodeHintType, String>();
hints.put(DecodeHintType.CHARACTER_SET, "utf-8");
//获取到待解析的图片
BitmapFactory.Options options = new BitmapFactory.Options();
//如果我们把inJustDecodeBounds设为true，那么BitmapFactory.decodeFile(String path, Options opt)
//并不会真的返回一个Bitmap给你，它仅仅会把它的宽，高取回来给你
options.inJustDecodeBounds = true;
//此时的bitmap是null，这段代码之后，options.outWidth 和 options.outHeight就是我们想要的宽和高了
Bitmap bitmap = BitmapFactory.decodeFile(bitmapPath,options);
//我们现在想取出来的图片的边长（二维码图片是正方形的）设置为400像素
/**
options.outHeight = 400;
options.outWidth = 400;
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeFile(bitmapPath, options);
*/
//以上这种做法，虽然把bitmap限定到了我们要的大小，但是并没有节约内存，如果要节约内存，我们还需要使用inSimpleSize这个属性
options.inSampleSize = options.outHeight / 400;
if(options.inSampleSize <= 0){
options.inSampleSize = 1; //防止其值小于或等于0
}
/**
* 辅助节约内存设置
*
* options.inPreferredConfig = Bitmap.Config.ARGB_4444; // 默认是Bitmap.Config.ARGB_8888
* options.inPurgeable = true;
* options.inInputShareable = true;
*/
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeFile(bitmapPath, options);
//新建一个RGBLuminanceSource对象，将bitmap图片传给此对象
RGBLuminanceSource rgbLuminanceSource = new RGBLuminanceSource(bitmap);
//将图片转换成二进制图片
BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(rgbLuminanceSource));
//初始化解析对象
QRCodeReader reader = new QRCodeReader();
//开始解析
Result result = null;
try {
result = reader.decode(binaryBitmap, hints);
} catch (Exception e) {
// TODO: handle exception
}
return result;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
//处理扫描结果（在界面上显示）
if (resultCode == RESULT_OK) {
Bundle bundle = data.getExtras();
String scanResult = bundle.getString("result");
resultTextView.setText(scanResult);
}
}
}然后长按识别二维码调用了RGBLuminanceSource这个类
public class RGBLuminanceSource extends LuminanceSource {
private byte bitmapPixels[];
protected RGBLuminanceSource(Bitmap bitmap) {
super(bitmap.getWidth(), bitmap.getHeight());
// 首先，要取得该图片的像素数组内容
int[] data = new int[bitmap.getWidth() * bitmap.getHeight()];
this.bitmapPixels = new byte[bitmap.getWidth() * bitmap.getHeight()];
bitmap.getPixels(data, 0, getWidth(), 0, 0, getWidth(), getHeight());
// 将int数组转换为byte数组，也就是取像素值中蓝色值部分作为辨析内容
for (int i = 0; i < data.length; i++) {
this.bitmapPixels[i] = (byte) data[i];
}
}
@Override
public byte[] getMatrix() {
// 返回我们生成好的像素数据
return bitmapPixels;
}
@Override
public byte[] getRow(int y, byte[] row) {
// 这里要得到指定行的像素数据
System.arraycopy(bitmapPixels, y * getWidth(), row, 0, getWidth());
return row;
}
}
相机识别二维码调用了CaptureActivity这个类
public class CaptureActivity extends Activity implements Callback {
private CaptureActivityHandler handler;
private ViewfinderView viewfinderView;
private boolean hasSurface;
private Vector<BarcodeFormat> decodeFormats;
private String characterSet;
private InactivityTimer inactivityTimer;
private MediaPlayer mediaPlayer;
private boolean playBeep;
private static final float BEEP_VOLUME = 0.10f;
private boolean vibrate;
private Button cancelScanButton;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.camera);
CameraManager.init(getApplication());
viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
cancelScanButton = (Button) this.findViewById(R.id.btn_cancel_scan);
hasSurface = false;
inactivityTimer = new InactivityTimer(this);
}
@Override
protected void onResume() {
super.onResume();
SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
SurfaceHolder surfaceHolder = surfaceView.getHolder();
if (hasSurface) {
initCamera(surfaceHolder);
} else {
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
decodeFormats = null;
characterSet = null;
playBeep = true;
AudioManager audioService = (AudioManager) getSystemService(AUDIO_SERVICE);
if (audioService.getRingerMode() != AudioManager.RINGER_MODE_NORMAL) {
playBeep = false;
}
initBeepSound();
vibrate = true;
//quit the scan view
cancelScanButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
CaptureActivity.this.finish();
}
});
}
@Override
protected void onPause() {
super.onPause();
if (handler != null) {
handler.quitSynchronously();
handler = null;
}
CameraManager.get().closeDriver();
}
@Override
protected void onDestroy() {
inactivityTimer.shutdown();
super.onDestroy();
}
/**
* Handler scan result
* @param result
* @param barcode
*/
public void handleDecode(Result result, Bitmap barcode) {
inactivityTimer.onActivity();
playBeepSoundAndVibrate();
String resultString = result.getText();
//FIXME
if (resultString.equals("")) {
//扫描失败
Toast.makeText(CaptureActivity.this, "Scan failed!", Toast.LENGTH_SHORT).show();
}else {
// System.out.println("Result:"+resultString);
Intent resultIntent = new Intent();
Bundle bundle = new Bundle();
bundle.putString("result", resultString);
resultIntent.putExtras(bundle);
this.setResult(RESULT_OK, resultIntent);
}
CaptureActivity.this.finish();
}
private void initCamera(SurfaceHolder surfaceHolder) {
try {
CameraManager.get().openDriver(surfaceHolder);
} catch (IOException ioe) {
return;
} catch (RuntimeException e) {
return;
}
if (handler == null) {
handler = new CaptureActivityHandler(this, decodeFormats,
characterSet);
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (!hasSurface) {
hasSurface = true;
initCamera(holder);
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
hasSurface = false;
}
public ViewfinderView getViewfinderView() {
return viewfinderView;
}
public Handler getHandler() {
return handler;
}
public void drawViewfinder() {
viewfinderView.drawViewfinder();
}
private void initBeepSound() {
if (playBeep && mediaPlayer == null) {
// The volume on STREAM_SYSTEM is not adjustable, and users found it
// too loud,
// so we now play on the music stream.
setVolumeControlStream(AudioManager.STREAM_MUSIC);
mediaPlayer = new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mediaPlayer.setOnCompletionListener(beepListener);
AssetFileDescriptor file = getResources().openRawResourceFd(
R.raw.beep);
try {
mediaPlayer.setDataSource(file.getFileDescriptor(),
file.getStartOffset(), file.getLength());
file.close();
mediaPlayer.setVolume(BEEP_VOLUME, BEEP_VOLUME);
mediaPlayer.prepare();
} catch (IOException e) {
mediaPlayer = null;
}
}
}
private static final long VIBRATE_DURATION = 200L;
private void playBeepSoundAndVibrate() {
if (playBeep && mediaPlayer != null) {
mediaPlayer.start();
}
if (vibrate) {
Vibrator vibrator = (Vibrator) getSystemService(VIBRATOR_SERVICE);
vibrator.vibrate(VIBRATE_DURATION);
}
}
/**
* When the beep has finished playing, rewind to queue up another one.
*/
private final OnCompletionListener beepListener = new OnCompletionListener() {
public void onCompletion(MediaPlayer mediaPlayer) {
mediaPlayer.seekTo(0);
}
};
}下面是主布局mian文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@android:color/white"
android:orientation="vertical" >
<Button
android:id="@+id/btn_scan_barcode"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:text="Open camera" />
<LinearLayout
android:orientation="horizontal"
android:layout_marginTop="10dp"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@android:color/black"
android:textSize="18sp"
android:text="Scan result：" />
<TextView
android:id="@+id/tv_scan_result"
android:layout_width="fill_parent"
android:textSize="18sp"
android:textColor="@android:color/black"
android:layout_height="wrap_content" />
</LinearLayout>
<EditText
android:id="@+id/et_qr_string"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:hint="Input the text"/>
<Button
android:id="@+id/btn_add_qrcode"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Generate QRcode" />
<ImageView
android:id="@+id/iv_qr_image"
android:layout_width="250dp"
android:layout_height="250dp"
android:scaleType="fitXY"
android:layout_marginTop="10dp"
android:layout_gravity="center"/>
</LinearLayout>详细了解 的请下载demo自己看，Demo中解决了在竖拍解码时二维码被拉伸的现象。
不过我遇到了一个问题是 二维码的扫描框调大后，扫描的灵敏度降低了，希望知道的朋友给指导下
有兴趣的可以下载Demo看一看
http://download.csdn.net/detail/shihuiyun/9537714
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