使用ZXing的 QRCodeWriter().encode方法生成的二维码往往边距有问题。

图片来自下方链接

详细原因已经有人分析过了。

我也用了一个简单粗暴但性能不高的方法：将二维码抠出来显示。以下是具体实现：
1、生成二维码矩阵:

BitMatrix bitMatrix = new QRCodeWriter().encode(url, BarcodeFormat.QR_CODE, widthPx, heightPx, hints);

2、找出二维码具体区域:

int width = bitMatrix.getWidth();
int height = bitMatrix.getHeight();

Rect bounds = new Rect();
bounds.left = Integer.MAX_VALUE;
bounds.top = Integer.MAX_VALUE;

for (int h = 0; h < height; h++) {
   for (int w = 0; w < width; w++) {
       if (bitMatrix.get(w, h)) {
           if (bounds.left > w) bounds.left = w;
           if (bounds.top > h) bounds.top = h;
       }
   }
}

for (int h = height - 1; h >= 0; h--) {
   for (int w = width - 1; w >= 0; w--) {
       if (bitMatrix.get(w, h)) {
           if (bounds.right < w) bounds.right = w;
           if (bounds.bottom < h) bounds.bottom = h;
       }
   }
}

3、生成Bitmap:

int[] pixels = new int[bounds.width() * bounds.height()];
int x = 0;
int y = 0;
for (int h = bounds.top; h < bounds.bottom; h++) {
    for (int w = bounds.left; w < bounds.right; w++) {
        pixels[y * bounds.width() + x] = bitMatrix.get(w, h) ? 0xff000000 : 0x00ffffff;
        x++;
    }
    x = 0;
    y++;
}

简单实现 代码没有优化。记录一下。