直接上代码：

public class MainActivity extends Activity {    private TextView tv;    private ImageView iv;    private int QR_WIDTH, QR_HEIGHT;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        tv = (TextView) findViewById(R.id.tv);        iv = (ImageView) findViewById(R.id.iv);        QR_WIDTH = 300;        QR_HEIGHT = 300;        createImage();    }    // 生成QR图    private void createImage() {        try {            // 需要引入core包            QRCodeWriter writer = new QRCodeWriter();            String text = tv.getText().toString();            if (text == null || "".equals(text) || text.length() < 1) {                return;            }            // 把输入的文本转为二维码            BitMatrix martix = writer.encode(text, BarcodeFormat.QR_CODE,                    QR_WIDTH, QR_HEIGHT);            Hashtable
     
       hints = new Hashtable
      
       ();            hints.put(EncodeHintType.CHARACTER_SET, "utf-8");            BitMatrix bitMatrix = new QRCodeWriter().encode(text,                    BarcodeFormat.QR_CODE, QR_WIDTH, QR_HEIGHT, hints);            int[] pixels = new int[QR_WIDTH * QR_HEIGHT];            for (int y = 0; y < QR_HEIGHT; y++) {                for (int x = 0; x < QR_WIDTH; x++) {                    if (bitMatrix.get(x, y)) {                        pixels[y * QR_WIDTH + x] = 0xff000000;                    } else {                        pixels[y * QR_WIDTH + x] = 0xffffffff;                    }                }            }            Bitmap bitmap = Bitmap.createBitmap(QR_WIDTH, QR_HEIGHT,                    Bitmap.Config.ARGB_8888);            bitmap.setPixels(pixels, 0, QR_WIDTH, 0, 0, QR_WIDTH, QR_HEIGHT);            iv.setImageBitmap(bitmap);        } catch (WriterException e) {            e.printStackTrace();        }    }}
      
     

要注意，需要导入一个core.jar包。见附件