生成二维码

在libs里导zxing包（在软件里）
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private ImageView iv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iv = (ImageView) findViewById(R.id.iv);
        Button bt1 = (Button) findViewById(R.id.bt1);
        Button bt2 = (Button) findViewById(R.id.bt2);
        bt1.setOnClickListener(this);
        bt2.setOnClickListener(this);
    }
    //生成二维码
    private Bitmap generateBitmap(String content, int width, int height) {
        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);
            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;
    }
    /**
     * 给二维码图片加背景
     */
    public static Bitmap addBackground(Bitmap foreground, Bitmap background) {
        int bgWidth = background.getWidth();
        int bgHeight = background.getHeight();
        int fgWidth = foreground.getWidth();
        int fgHeight = foreground.getHeight();
        Bitmap newmap = Bitmap
                .createBitmap(bgWidth, bgHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(newmap);
        canvas.drawBitmap(background, 0, 0, null);
        canvas.drawBitmap(foreground, (bgWidth - fgWidth) / 2,
                (bgHeight - fgHeight) * 3 / 5 + 70, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        canvas.restore();
        return newmap;
    }
     * 添加图标
    private 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;
    }
    @Override
    public void onClick(View v) {
        Bitmap bitmap = null;
        switch (v.getId()) {
            case R.id.bt1:
                bitmap = generateBitmap("我爱你", 500, 500);
                //  Bitmap bitmap2 = addBackground(bitmap, BitmapFactory.decodeResource(getResources(), R.mipmap.b));
                iv.setImageBitmap(bitmap);
                break;
            case R.id.bt2:
                bitmap = generateBitmap("http://blog.youkuaiyun.com/lmj623565791/article/details/38067475/", 400, 400);
                Bitmap logo = BitmapFactory.decodeResource(getResources(), R.drawable.a);
                Bitmap bitmap1 = addLogo(bitmap, logo);
                iv.setImageBitmap(bitmap1);
                break;
        }
    }
}
XML:
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:gravity="center_horizontal"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >
    <Button
        android:id="@+id/bt1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="生成二维码"
        />
    <Button
        android:id="@+id/bt2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="自定义生成二维码"
        />
    <ImageView
        android:id="@+id/iv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</LinearLayout>