Android Using ZXing Generate QR Code

2019-02-05 20:37发布

站内文章 / Java
61 0 0

问题:

I was having some problem when trying to generate QR code in Android Programming. Here is the Tutorial I followed. When my generate button on click, I am calling this method:

private void generateQR(){
    String qrInputText = "test";

    //Find screen size
    WindowManager manager = (WindowManager) getSystemService(WINDOW_SERVICE);
    Display display = manager.getDefaultDisplay();
    Point point = new Point();
    display.getSize(point);
    int width = point.x;
    int height = point.y;
    int smallerDimension = width < height ? width : height;
    smallerDimension = smallerDimension * 3/4;

    //Encode with a QR Code image
    QRCodeEncoder qrCodeEncoder = new QRCodeEncoder(
        qrInputText, 
        null, 
        Contents.Type.TEXT,  
        BarcodeFormat.QR_CODE.toString(), 
        smallerDimension
    );
    try {
        Bitmap bitmap = qrCodeEncoder.encodeAsBitmap();
        ImageView myImage = (ImageView) findViewById(R.id.ivImage);
        myImage.setImageBitmap(bitmap);
    } catch (WriterException e) {
        e.printStackTrace();
    }
}

And then for the QRCodeEncoder and Contents classes, I followed the one in the tutorial. However, when I click on generate, I am getting the error message as:

01-30 16:37:03.093: I/dalvikvm(1069): Could not find method com.google.zxing.BarcodeFormat.valueOf, referenced from method com.example.qrcodescan.QRCodeEncoder.encodeContents
01-30 16:37:03.093: W/dalvikvm(1069): VFY: unable to resolve static method 338: Lcom/google/zxing/BarcodeFormat;.valueOf (Ljava/lang/String;)Lcom/google/zxing/BarcodeFormat;
01-30 16:37:03.093: D/dalvikvm(1069): VFY: replacing opcode 0x71 at 0x0005
01-30 16:37:03.093: W/dalvikvm(1069): VFY: unable to resolve static field 287 (QR_CODE) in Lcom/google/zxing/BarcodeFormat;
01-30 16:37:03.093: D/dalvikvm(1069): VFY: replacing opcode 0x62 at 0x0011
01-30 16:37:03.093: W/dalvikvm(1069): VFY: unable to resolve static field 287 (QR_CODE) in Lcom/google/zxing/BarcodeFormat;
01-30 16:37:03.093: D/dalvikvm(1069): VFY: replacing opcode 0x62 at 0x0015
01-30 16:37:03.093: W/dalvikvm(1069): VFY: unable to resolve static field 294 (CHARACTER_SET) in Lcom/google/zxing/EncodeHintType;
01-30 16:37:03.093: D/dalvikvm(1069): VFY: replacing opcode 0x62 at 0x0018
01-30 16:37:03.093: E/dalvikvm(1069): Could not find class 'com.google.zxing.MultiFormatWriter', referenced from method com.example.qrcodescan.QRCodeEncoder.encodeAsBitmap
01-30 16:37:03.093: W/dalvikvm(1069): VFY: unable to resolve new-instance 150 (Lcom/google/zxing/MultiFormatWriter;) in Lcom/example/qrcodescan/QRCodeEncoder;
01-30 16:37:03.093: D/dalvikvm(1069): VFY: replacing opcode 0x22 at 0x001d
01-30 16:37:03.093: D/dalvikvm(1069): DexOpt: unable to opt direct call 0x0159 at 0x1f in Lcom/example/qrcodescan/QRCodeEncoder;.encodeAsBitmap
01-30 16:37:03.093: D/AndroidRuntime(1069): Shutting down VM
01-30 16:37:03.093: W/dalvikvm(1069): threadid=1: thread exiting with uncaught exception (group=0x40c341f8)
01-30 16:37:03.101: E/AndroidRuntime(1069): FATAL EXCEPTION: main
01-30 16:37:03.101: E/AndroidRuntime(1069): java.lang.NoClassDefFoundError: com.google.zxing.BarcodeFormat
01-30 16:37:03.101: E/AndroidRuntime(1069):     at com.example.qrcodescan.MainActivity.generateQR(MainActivity.java:95)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at com.example.qrcodescan.MainActivity.access$0(MainActivity.java:77)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at com.example.qrcodescan.MainActivity$2.onClick(MainActivity.java:54)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at android.view.View.performClick(View.java:3620)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at android.view.View$PerformClick.run(View.java:14292)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at android.os.Handler.handleCallback(Handler.java:605)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at android.os.Looper.loop(Looper.java:137)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at android.app.ActivityThread.main(ActivityThread.java:4512)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at java.lang.reflect.Method.invokeNative(Native Method)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at java.lang.reflect.Method.invoke(Method.java:511)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:982)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749)
01-30 16:37:03.101: E/AndroidRuntime(1069):     at dalvik.system.NativeStart.main(Native Method)

I did added the core.jar under libs folder. Any ideas? Thanks in advance.

回答1:

Here is how you can generate an image with QR code from a string -

First add the following line to build.gradle file in your Android Studio project:

dependencies {
    ....
    compile 'com.google.zxing:core:3.2.1'
}

Or if still using Eclipse with ADT-plugin add ZXing's core.jar from Maven repository to the libs subdir of your Eclipse ADT project (here fullscreen):

And then use the sample code from my MainActivity.java:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageView imageView = (ImageView) findViewById(R.id.qrCode);
    try {
        Bitmap bitmap = encodeAsBitmap(STR);
        imageView.setImageBitmap(bitmap);
    } catch (WriterException e) {
        e.printStackTrace();
    }
}

Bitmap encodeAsBitmap(String str) throws WriterException {
    BitMatrix result;
    try {
        result = new MultiFormatWriter().encode(str, 
            BarcodeFormat.QR_CODE, WIDTH, WIDTH, null);
    } catch (IllegalArgumentException iae) {
        // Unsupported format
        return null;
    }
    int w = result.getWidth();
    int h = result.getHeight();
    int[] pixels = new int[w * h];
    for (int y = 0; y < h; y++) {
        int offset = y * w;
        for (int x = 0; x < w; x++) {
            pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
        }
    }
    Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
    bitmap.setPixels(pixels, 0, width, 0, 0, w, h);
    return bitmap;
}


回答2:

ZXing library can provide easy way.

Origin is : Generate QRCode Android Example

add in dependencies

compile 'com.google.zxing:core:3.2.1'

Here is the method to conver string into QR Image 

private Bitmap TextToImageEncode(String Value) throws WriterException {
        BitMatrix bitMatrix;
        try {
            bitMatrix = new MultiFormatWriter().encode(
                    Value,
                    BarcodeFormat.DATA_MATRIX.QR_CODE,
                    QRcodeWidth, QRcodeWidth, null
            );

        } catch (IllegalArgumentException Illegalargumentexception) {

            return null;
        }
        int bitMatrixWidth = bitMatrix.getWidth();

        int bitMatrixHeight = bitMatrix.getHeight();

        int[] pixels = new int[bitMatrixWidth * bitMatrixHeight];

        for (int y = 0; y < bitMatrixHeight; y++) {
            int offset = y * bitMatrixWidth;

            for (int x = 0; x < bitMatrixWidth; x++) {

                pixels[offset + x] = bitMatrix.get(x, y) ?
                        getResources().getColor(R.color.black):getResources().getColor(R.color.white);
            }
        }
        Bitmap bitmap = Bitmap.createBitmap(bitMatrixWidth, bitMatrixHeight, Bitmap.Config.ARGB_4444);

        bitmap.setPixels(pixels, 0, 500, 0, 0, bitMatrixWidth, bitMatrixHeight);
        return bitmap;
    }

Save geneated qr image 

 public String saveImage(Bitmap myBitmap) {
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        myBitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
        File wallpaperDirectory = new File(
                Environment.getExternalStorageDirectory() + IMAGE_DIRECTORY);
        // have the object build the directory structure, if needed.

        if (!wallpaperDirectory.exists()) {
            Log.d("dirrrrrr", "" + wallpaperDirectory.mkdirs());
            wallpaperDirectory.mkdirs();
        }

        try {
            File f = new File(wallpaperDirectory, Calendar.getInstance()
                    .getTimeInMillis() + ".jpg");
            f.createNewFile();   //give read write permission
            FileOutputStream fo = new FileOutputStream(f);
            fo.write(bytes.toByteArray());
            MediaScannerConnection.scanFile(this,
                    new String[]{f.getPath()},
                    new String[]{"image/jpeg"}, null);
            fo.close();
            Log.d("TAG", "File Saved::--->" + f.getAbsolutePath());

            return f.getAbsolutePath();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        return "";

    }


回答3:

public static int white = 0xFFFFFFFF;
public static int black = 0xFF000000;
public final static int WIDTH = 500;


try
    {
        Bitmap bmp =  encodeAsBitmap("Life is a bitch");
        imgView.setImageBitmap(bmp);
    } catch (Exception e) {
        e.printStackTrace();
    }


Bitmap encodeAsBitmap(String str) throws WriterException {
    BitMatrix result;
    Bitmap bitmap=null;
    try
    {
        result = new MultiFormatWriter().encode(str,
                BarcodeFormat.QR_CODE, WIDTH, WIDTH, null);

        int w = result.getWidth();
        int h = result.getHeight();
        int[] pixels = new int[w * h];
        for (int y = 0; y < h; y++) {
            int offset = y * w;
            for (int x = 0; x < w; x++) {
                pixels[offset + x] = result.get(x, y) ? black:white;
            }
        }
        bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        bitmap.setPixels(pixels, 0, WIDTH, 0, 0, w, h);
    } catch (Exception iae) {
        iae.printStackTrace();
        return null;
    }
    return bitmap;
}


回答4:

Following code worked for me:

...
String QRcode = "...";
new generateQrcode(qrcodeImageview).execute(QRcode);
...
private class generateQrcode extends AsyncTask<String, Void, Bitmap> {
        public final static int WIDTH = 400;
        ImageView bmImage;

        public generateQrcode(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String Value = urls[0];
            com.google.zxing.Writer writer = new QRCodeWriter();
            Bitmap bitmap = null;
            BitMatrix bitMatrix = null;
            try {
                bitMatrix = writer.encode(Value, com.google.zxing.BarcodeFormat.QR_CODE, WIDTH, WIDTH,
                        ImmutableMap.of(EncodeHintType.MARGIN, 1));
                bitmap = Bitmap.createBitmap(400, 400, Bitmap.Config.ARGB_8888);
                for (int i = 0; i < 400; i++) {
                    for (int j = 0; j < 400; j++) {
                        bitmap.setPixel(i, j, bitMatrix.get(i, j) ? Color.BLACK
                                : Color.WHITE);
                    }
                }
            } catch (WriterException e) {
                e.printStackTrace();
            }
            return bitmap;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }


标签： java android zxing qr-code
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