zxing 黑屏 无法显示图像问题 及中文乱码问题解决

修改zxing/camera/CameraConfigurationManager.java文件此函数findBestPreviewSizeValue（）为：

private static Point findBestPreviewSizeValue(CharSequence previewSizeValueString, Point screenResolution) {
    int bestX = 0;
    int bestY = 0;
    int diff = Integer.MAX_VALUE;
    
    int maybeOKX = 0;
    int maybeOKY = 0;
    float maybeOKScale = -1;
    for (String previewSize : COMMA_PATTERN.split(previewSizeValueString)) {

    	Print.d(TAG, "previewSize = " + previewSize);
      previewSize = previewSize.trim();
      int dimPosition = previewSize.indexOf('x');
      if (dimPosition < 0) {
        Log.w(TAG, "Bad preview-size: " + previewSize);
        continue;
      }

      int newX;
      int newY;
      
      try {
        newX = Integer.parseInt(previewSize.substring(0, dimPosition));
        newY = Integer.parseInt(previewSize.substring(dimPosition + 1));
      } catch (NumberFormatException nfe) {
        Log.w(TAG, "Bad preview-size: " + previewSize);
        continue;
      }

      int newDiff = Math.abs(newX - screenResolution.x) + Math.abs(newY - screenResolution.y);
      boolean isScaleRight = ((double)newX / (double)screenResolution.y == (double)newY / (double)screenResolution.x);
      Log.d(TAG, isScaleRight + "##" + newX + " / " + screenResolution.y + " == " + newY + " / " + screenResolution.x);
      
      
      if (newDiff == 0) {
        bestX = newX;
        bestY = newY;
        break;
      } else if (isScaleRight && newDiff < diff) {
        bestX = newX;
        bestY = newY;
        diff = newDiff;
      } else {
    	  float scale = Math.abs((float)((float)newX / (float)newY) - ((float)screenResolution.x - (float)screenResolution.y));
    	  if (maybeOKScale == -1 || scale < maybeOKScale) {
    		  maybeOKX = newX;
    		  maybeOKY = newY;
    		  maybeOKScale = scale;
    	  }
      }
    }

    if (bestX > 0 && bestY > 0) {
      return new Point(bestX, bestY);
    }
    
    Print.e(TAG, "return maybeOK....x = " + maybeOKX + ", y = " + maybeOKY);
    //640x480,1024x768
    return new Point(maybeOKX, maybeOKY);
//    return null;
  }

zxing生成二维码的中文乱码问题原因不详，解决方法：

修改core目录下的com.google.zxing.qrcode.encoder.Encoder.java文件，static final String DEFAULT_BYTE_MODE_ENCODING = "ISO8859-1";修改为UTF-8

然后重新打个zxingcore源码的jar包，直接在eclipse的export中就可以导出jar包了

网上有些讲解此类问题的文章，具体谷歌“zxing utf8 chinese”