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;    }}