如何为 Android 应用程序生成二维码？

Have you looked into ZXING? I've been using it successfully to create barcodes. You can see a full working example in the bitcoin application src

// this is a small sample use of the QRCodeEncoder class from zxing
try {
// generate a 150x150 QR code
Bitmap bm = encodeAsBitmap(barcode_content, BarcodeFormat.QR_CODE, 150, 150);


if(bm != null) {
image_view.setImageBitmap(bm);
}
} catch (WriterException e) { //eek }

zxing does not (only) provide a web API; really, that is Google providing the API, from source code that was later open-sourced in the project.

As Rob says here you can use the Java source code for the QR code encoder to create a raw barcode and then render it as a Bitmap.

I can offer an easier way still. You can call Barcode Scanner by Intent to encode a barcode. You need just a few lines of code, and two classes from the project, under android-integration. The main one is IntentIntegrator. Just call shareText().

with zxing this is my code for create QR

 QRCodeWriter writer = new QRCodeWriter();
try {
BitMatrix bitMatrix = writer.encode(content, BarcodeFormat.QR_CODE, 512, 512);
int width = bitMatrix.getWidth();
int height = bitMatrix.getHeight();
Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
bmp.setPixel(x, y, bitMatrix.get(x, y) ? Color.BLACK : Color.WHITE);
}
}
((ImageView) findViewById(R.id.img_result_qr)).setImageBitmap(bmp);


} catch (WriterException e) {
e.printStackTrace();
}

I used zxing-1.3 jar and I had to make some changes implementing code from other answers, so I will leave my solution for others. I did the following:

1) find zxing-1.3.jar, download it and add in properties (add external jar).

2) in my activity layout add ImageView and name it (in my example it was tnsd_iv_qr).

3) include code in my activity to create qr image (in this example I was creating QR for bitcoin payments):

    QRCodeWriter writer = new QRCodeWriter();
ImageView tnsd_iv_qr = (ImageView)findViewById(R.id.tnsd_iv_qr);
try {
ByteMatrix bitMatrix = writer.encode("bitcoin:"+btc_acc_adress+"?amount="+amountBTC, BarcodeFormat.QR_CODE, 512, 512);
int width = 512;
int height = 512;
Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
if (bitMatrix.get(x, y)==0)
bmp.setPixel(x, y, Color.BLACK);
else
bmp.setPixel(x, y, Color.WHITE);
}
}
tnsd_iv_qr.setImageBitmap(bmp);
} catch (WriterException e) {
//Log.e("QR ERROR", ""+e);


}

If someone is wondering, variable "btc_acc_adress" is a String (with BTC adress), amountBTC is a double, with, of course, transaction amount.

Here is my simple and working function to generate a Bitmap! I Use ZXing1.3.jar only! I've also set Correction Level to High!

PS: x and y are reversed, it's normal, because bitMatrix reverse x and y. This code works perfectly with a square image.

public static Bitmap generateQrCode(String myCodeText) throws WriterException {
Hashtable<EncodeHintType, ErrorCorrectionLevel> hintMap = new Hashtable<EncodeHintType, ErrorCorrectionLevel>();
hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H); // H = 30% damage


QRCodeWriter qrCodeWriter = new QRCodeWriter();


int size = 256;


ByteMatrix bitMatrix = qrCodeWriter.encode(myCodeText,BarcodeFormat.QR_CODE, size, size, hintMap);
int width = bitMatrix.width();
Bitmap bmp = Bitmap.createBitmap(width, width, Bitmap.Config.RGB_565);
for (int x = 0; x < width; x++) {
for (int y = 0; y < width; y++) {
bmp.setPixel(y, x, bitMatrix.get(x, y)==0 ? Color.BLACK : Color.WHITE);
}
}
return bmp;
}

EDIT

It's faster to use bitmap.setPixels(...) with a pixel int array instead of bitmap.setPixel one by one:

        BitMatrix bitMatrix = writer.encode(inputValue, BarcodeFormat.QR_CODE, size, size);
int width = bitMatrix.getWidth();
int height = bitMatrix.getHeight();
int[] pixels = new int[width * height];
for (int y = 0; y < height; y++) {
int offset = y * width;
for (int x = 0; x < width; x++) {
pixels[offset + x] = bitMatrix.get(x, y) ? BLACK : WHITE;
}
}


bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
bitmap.setPixels(pixels, 0, width, 0, 0, width, height);

Maybe this old topic but i found this library is very helpful and easy to use

QRGen

example for using it in android

 Bitmap myBitmap = QRCode.from("www.example.org").bitmap();
ImageView myImage = (ImageView) findViewById(R.id.imageView);
myImage.setImageBitmap(myBitmap);