Android 二维码生成 带logo

首先需要下载 core-x.x.x.jar文件并依赖。

public class MainActivity extends AppCompatActivity {

    private ImageView ivQrCode;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ivQrCode = (ImageView) findViewById(R.id.iv_qr_code);

        findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                click();
            }
        });
    }


    private void click() {
        //生成二维码
        Bitmap qrCodeBitmap = generateBitmap(MainActivity.this, "这里是二维码的内容", 100, 100);
        //生成二维码中需要显示的图标
        Bitmap logoBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher_round);
        //生成带图标的二维码
        Bitmap qrCodeWithLogo = addLogo(qrCodeBitmap, logoBitmap);
        ivQrCode.setImageBitmap(qrCodeWithLogo);
    }


    //这个是生成二维码的Bitmap
    public Bitmap generateBitmap(Context context, String content, int widthDp, int heightDp) {

        int width = DensityUtils.dip2px(context, widthDp);
        int height = DensityUtils.dip2px(context, heightDp);
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        Map<EncodeHintType, String> hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
        try {
            BitMatrix encode = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, width, height, hints);
            int[] pixels = new int[width * height];
            for (int i = 0; i < height; i++) {
                for (int j = 0; j < width; j++) {
                    if (encode.get(j, i)) {
                        pixels[i * width + j] = 0x00000000;
                    } else {
                        pixels[i * width + j] = 0xffffffff;
                    }
                }
            }
            return Bitmap.createBitmap(pixels, 0, width, width, height, Bitmap.Config.RGB_565);
        } catch (WriterException e) {
            e.printStackTrace();
        }
        return null;
    }

    //给二维码加上图标
    public Bitmap addLogo(Bitmap qrBitmap, Bitmap logoBitmap) {
        int qrBitmapWidth = qrBitmap.getWidth();
        int qrBitmapHeight = qrBitmap.getHeight();
        int logoBitmapWidth = logoBitmap.getWidth();
        int logoBitmapHeight = logoBitmap.getHeight();
        Bitmap blankBitmap = Bitmap.createBitmap(qrBitmapWidth, qrBitmapHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(blankBitmap);
        canvas.drawBitmap(qrBitmap, 0, 0, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        float scaleSize = 1.0f;
        while ((logoBitmapWidth / scaleSize) > (qrBitmapWidth / 5) || (logoBitmapHeight / scaleSize) > (qrBitmapHeight / 5)) {
            scaleSize *= 2;
        }
        float sx = 1.0f / scaleSize;
        canvas.scale(sx, sx, qrBitmapWidth / 2, qrBitmapHeight / 2);
        canvas.drawBitmap(logoBitmap, (qrBitmapWidth - logoBitmapWidth) / 2, (qrBitmapHeight - logoBitmapHeight) / 2, null);
        canvas.restore();
        return blankBitmap;
    }
}

DensityUtils类的代码内容是：

public class DensityUtils {

    private static final float DOT_FIVE = 0.5f;
    
    /**
     * dip to px
     *
     * @param context
     * @param dip
     * @return
     */
    public static int dip2px(Context context, float dip) {
        float density = getDensity(context);
        return (int) (dip * density + DensityUtils.DOT_FIVE);
    }

    /**
     * px to dip
     *
     * @param context
     * @param px
     * @return
     */
    public static int px2dip(Context context, float px) {
        float density = getDensity(context);
        return (int) (px / density + DOT_FIVE);
    }

    private static DisplayMetrics sDisplayMetrics;

    /**
     * get screen width
     *
     * @param context
     * @return
     */
    public static int getDisplayWidth(Context context) {
        initDisplayMetrics(context);
        return sDisplayMetrics.widthPixels;
    }

    /**
     * get screen height
     *
     * @param context
     * @return
     */
    public static int getDisplayHeight(Context context) {
        initDisplayMetrics(context);
        return sDisplayMetrics.heightPixels;
    }

    /**
     * get screen density
     *
     * @param context
     * @return
     */
    public static float getDensity(Context context) {
        initDisplayMetrics(context);
        return sDisplayMetrics.density;
    }


    /**
     * get screen density dpi
     *
     * @param context
     * @return
     */
    public static int getDensityDpi(Context context) {
        initDisplayMetrics(context);
        return sDisplayMetrics.densityDpi;
    }

    /**
     * init display metrics
     *
     * @param context
     */
    private static synchronized void initDisplayMetrics(Context context) {
        sDisplayMetrics = context.getResources().getDisplayMetrics();
    }

    /**
     * is landscape
     *
     * @param context
     * @return
     */
    public static boolean isLandscape(Context context) {
        return context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE;
    }

    /**
     * is portrait
     *
     * @param context
     * @return
     */
    public static boolean isPortrait(Context context) {
        return context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT;
    }

    /**
     * get status height
     *
     * @param context
     * @return
     */
    public static int getStatusHeight(Context context) {

        int statusHeight = -1;
        try {
            Class<?> clazz = Class.forName("com.android.internal.R$dimen");
            Object object = clazz.newInstance();
            int height = Integer.parseInt(clazz.getField("status_bar_height")
                    .get(object).toString());
            statusHeight = context.getResources().getDimensionPixelSize(height);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return statusHeight;
    }

}