Zxing掃描

在我們是Zxing框架進行二維碼掃描的時候，會發現，現在手機隨着分辨率的增加，那個掃描框會越來越小解決辦法：

1：找到CameraManager類，最上面四行參數就是設置寬高的，

 private static final int MIN_FRAME_WIDTH = (int)  DensityUtils.dp2px(MyApplication.getInstance(),180);
  private static final int MIN_FRAME_HEIGHT = (int)  DensityUtils.dp2px(MyApplication.getInstance(),180);
  private static final int MAX_FRAME_WIDTH = (int)  DensityUtils.dp2px(MyApplication.getInstance(),240);
  private static final int MAX_FRAME_HEIGHT = (int)  DensityUtils.dp2px(MyApplication.getInstance(),240);

第二個問題：每次掃描後圖片都會壓縮下

解決方法：在Zxing包下的camera包下找到CameraConfigurationManager.java類，修改：

搜索initFromCameraParameters 這個方法，在該方法下找到  Log.d(TAG, "Screen resolution: " + screenResolution);  這句話，在這句話下面添加這些代碼：

Point screenResolutionForCamera = new Point();  
        screenResolutionForCamera.x = screenResolution.x;  
        screenResolutionForCamera.y = screenResolution.y;  
        if (screenResolution.x < screenResolution.y) {  
        screenResolutionForCamera.x = screenResolution.y;  
        screenResolutionForCamera.y = screenResolution.x;  
        }  

然後下面有一行這樣的代碼：

cameraResolution = getCameraResolution(parameters, screenResolution);

中的screenResolution改爲  screenResolutionForCamera

第三個問題：調整掃描區域 優化取圖速度

Zxing 是google提供的二維碼掃描工程

Demo本身默認的掃圖區域最大隻有 360*480    需要拉開很遠的距離才能將整個二維碼掃描到

因此需要我們自己調整取圖大小

 

在CameraManager.java這個類中進行調整

默認的大小是 以下這4個參數 

//  private static final int MIN_FRAME_WIDTH = 240;
//  private static final int MIN_FRAME_HEIGHT = 240;
//  private static final int MAX_FRAME_WIDTH = 480;
//  private static final int MAX_FRAME_HEIGHT = 360;

參數實際在 getFramingRect() 方法中起作用

以下是原本Demo中提供的

/**
  * Calculates the framing rect which the UI should draw to show the user where to place the
  * barcode. This target helps with alignment as well as forces the user to hold the device
  * far enough away to ensure the image will be in focus.
  *
  * @return The rectangle to draw on screen in window coordinates.
  */
 public Rect getFramingRect() {
   Point screenResolution = configManager.getScreenResolution();
   if (framingRect == null) {
     if (camera == null) {
       return null;
     }

     //原生
     int width = screenResolution.x * 3 / 4;
     if (width < MIN_FRAME_WIDTH) {
       width = MIN_FRAME_WIDTH;
     } else if (width > MAX_FRAME_WIDTH) {
       width = MAX_FRAME_WIDTH;
     }
     int height = screenResolution.y * 3 / 4;
     if (height < MIN_FRAME_HEIGHT) {
       height = MIN_FRAME_HEIGHT;
     } else if (height > MAX_FRAME_HEIGHT) {
       height = MAX_FRAME_HEIGHT;
     }
     int leftOffset = (screenResolution.x - width) / 2;
     int topOffset = (screenResolution.y - height) / 2;
     framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
     Log.d(TAG, "Calculated framing rect: " + framingRect);
   }
   return framingRect;
 }

我將代碼改成了

public Rect getFramingRect() {
  Point screenResolution = configManager.getScreenResolution();
  if (framingRect == null) {
    if (camera == null) {
      return null;
    }

  //修改之後
   int width = screenResolution.x * 3 / 4;

  int leftOffset = (screenResolution.x - width) / 2;
  int topOffset = (screenResolution.y - width ) / 3;
  framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + width );


    Log.d(TAG, "Calculated framing rect: " + framingRect);
  }
  return framingRect;
}

當然...取圖改的這麼大   會多佔一點內存....相應的掃描的時候快得多