關於條碼掃描Zxing，需要掃描時直立顯示：

關於條碼掃描Zxing，需要掃描時直立顯示：

android提供的SDK（android.hardware.Camera）裡大概不能正常的使用直立顯示（portrait layout）加載照相機，當用直立顯示模式加載照相機時會產生以下情況：

1.照相機成像左傾90度(傾斜)；
2.照相機成像長寬比例不對(失比)。



基本上解決辦法如下：

1、在AndroidManifest.xml裡面配置一下 ，使CaptureActivity属性為portrait：android:screenOrientation="portrait"

2、如果只是單純的想改變照相機成像的方向，只需要在com.google.zxing.client.android.camera下的   CameraConfigurationManager類別中增加方法  

protected void setDisplayOrientation(Camera camera, int angle) {
        Method downPolymorphic;
　　 try {        
　　　　downPolymorphic = camera.getClass().getMethod("setDisplayOrientation", new Class[] { int.class });
           if (downPolymorphic != null)
　　　　downPolymorphic.invoke(camera, new Object[] { angle });
　　} catch (Exception e1) {         }
}

然後在方法void setDesiredCameraParameters(Camera camera)｛｝中調用， setDisplayOrientation(camera, 90);     具體位置在camera.setParameters(parameters);語句前面。

3、改變完方向你會發現方向改變可可分辨率會變得很低，接下來就是優化了

1）首先在類別CameraManager.java中把
rect.left = rect.left * cameraResolution.x / screenResolution.x;
rect.right = rect.right * cameraResolution.x / screenResolution.x;
rect.top = rect.top * cameraResolution.y / screenResolution.y;
rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;

替換成
rect.left = rect.left * cameraResolution.y / screenResolution.x;
rect.right = rect.right * cameraResolution.y / screenResolution.x;
rect.top = rect.top * cameraResolution.x / screenResolution.y;
rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;

（2）然後是在DecodeHandler類別中的方法private void decode(byte[] data,int width,int height){｝中添加

byte[] rotatedData = new byte[data.length];
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++)
rotatedData[x * height + height - y - 1] = data[x + y * width];

（3）再就是CameraConfigurationManager類別中的方法void initFromCameraParameters(Camera camera){｝中添加如下代碼：

Point screenResolutionForCamera = new Point();
screenResolutionForCamera.x = screenResolution.x;
screenResolutionForCamera.y = screenResolution.y;

// preview size is always something like 480*320, other 320*480
if (screenResolution.x < screenResolution.y) {
   screenResolutionForCamera.x = screenResolution.y;
  screenResolutionForCamera.y = screenResolution.x;