我创建了一个可以扫描二维码的应用程序，它适用于除三星Galaxy s4 之外的所有Android设备。
在使用Galaxy s4设备时，App不扫描任何QR码。
现在这个拥有Android 4.2.2版本的Galaxy s4，我也在其他具有相同Android版本（4.2.2）的设备中验证了我的应用程序，如Nexus-4，它可以正常使用它。
是否有其他硬件用于扫描Galaxy s4中的QR码？
需要帮助解决这个奇怪的问题！
以下是我在我的应用程序中使用的代码。
CameraManager.java
/**
* This object wraps the Camera service object and expects to be the only one talking to it. The
* implementation encapsulates the steps needed to take preview-sized images, which are used for
* both preview and decoding.
*
* @author dswitkin@google.com (Daniel Switkin)
*/
public final class CameraManager {
private static final String TAG = CameraManager.class.getSimpleName();
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;
private static CameraManager cameraManager;
static final int SDK_INT; // Later we can use Build.VERSION.SDK_INT
static {
int sdkInt;
try {
sdkInt = Integer.parseInt(Build.VERSION.SDK);
} catch (NumberFormatException nfe) {
// Just to be safe
sdkInt = 10000;
}
SDK_INT = sdkInt;
}
private final Context context;
private final CameraConfigurationManager configManager;
private Camera camera;
private Rect framingRect;
private Rect framingRectInPreview;
private boolean initialized;
private boolean previewing;
private boolean reverseImage;
private final boolean useOneShotPreviewCallback;
/**
* Preview frames are delivered here, which we pass on to the registered handler. Make sure to
* clear the handler so it will only receive one message.
*/
private final PreviewCallback previewCallback;
/** Autofocus callbacks arrive here, and are dispatched to the Handler which requested them. */
private final AutoFocusCallback autoFocusCallback;
/**
* Initializes this static object with the Context of the calling Activity.
*
* @param context The Activity which wants to use the camera.
*/
public static void init(Context context) {
if (cameraManager == null) {
cameraManager = new CameraManager(context);
}
}
/**
* Gets the CameraManager singleton instance.
*
* @return A reference to the CameraManager singleton.
*/
public static CameraManager get() {
return cameraManager;
}
private CameraManager(Context context) {
this.context = context;
this.configManager = new CameraConfigurationManager(context);
// Camera.setOneShotPreviewCallback() has a race condition in Cupcake, so we use the older
// Camera.setPreviewCallback() on 1.5 and earlier. For Donut and later, we need to use
// the more efficient one shot callback, as the older one can swamp the system and cause it
// to run out of memory. We can't use SDK_INT because it was introduced in the Donut SDK.
useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) > 3; // 3 = Cupcake
previewCallback = new PreviewCallback(configManager, useOneShotPreviewCallback);
autoFocusCallback = new AutoFocusCallback();
}
/**
* Opens the camera driver and initializes the hardware parameters.
*
* @param holder The surface object which the camera will draw preview frames into.
* @throws IOException Indicates the camera driver failed to open.
*/
public void openDriver(SurfaceHolder holder) throws IOException {
if (camera == null) {
camera = Camera.open();
if (camera == null) {
throw new IOException();
}
}
camera.setPreviewDisplay(holder);
if (!initialized) {
initialized = true;
configManager.initFromCameraParameters(camera);
}
configManager.setDesiredCameraParameters(camera);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
reverseImage = prefs.getBoolean(PreferencesActivity.KEY_REVERSE_IMAGE, false);
if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) {
FlashlightManager.enableFlashlight();
}
}
/**
* Closes the camera driver if still in use.
*/
public void closeDriver() {
if (camera != null) {
FlashlightManager.disableFlashlight();
camera.release();
camera = null;
// Make sure to clear these each time we close the camera, so that any scanning rect
// requested by intent is forgotten.
framingRect = null;
framingRectInPreview = null;
}
}
/**
* Asks the camera hardware to begin drawing preview frames to the screen.
*/
public void startPreview() {
if (camera != null && !previewing) {
camera.startPreview();
previewing = true;
}
}
/**
* Tells the camera to stop drawing preview frames.
*/
public void stopPreview() {
if (camera != null && previewing) {
if (!useOneShotPreviewCallback) {
camera.setPreviewCallback(null);
}
camera.stopPreview();
previewCallback.setHandler(null, 0);
autoFocusCallback.setHandler(null, 0);
previewing = false;
}
}
/**
* A single preview frame will be returned to the handler supplied. The data will arrive as byte[]
* in the message.obj field, with width and height encoded as message.arg1 and message.arg2,
* respectively.
*
* @param handler The handler to send the message to.
* @param message The what field of the message to be sent.
*/
public void requestPreviewFrame(Handler handler, int message) {
if (camera != null && previewing) {
previewCallback.setHandler(handler, message);
if (useOneShotPreviewCallback) {
camera.setOneShotPreviewCallback(previewCallback);
} else {
camera.setPreviewCallback(previewCallback);
}
}
}
/**
* Asks the camera hardware to perform an autofocus.
*
* @param handler The Handler to notify when the autofocus completes.
* @param message The message to deliver.
*/
public void requestAutoFocus(Handler handler, int message) {
if (camera != null && previewing) {
autoFocusCallback.setHandler(handler, message);
//Log.d(TAG, "Requesting auto-focus callback");
camera.autoFocus(autoFocusCallback);
}
}
/**
* 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() {
if (framingRect == null) {
if (camera == null) {
return null;
}
Point screenResolution = configManager.getScreenResolution();
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;
}
/**
* Like {@link #getFramingRect} but coordinates are in terms of the preview frame,
* not UI / screen.
*/
public Rect getFramingRectInPreview() {
if (framingRectInPreview == null) {
Rect rect = new Rect(getFramingRect());
Point cameraResolution = configManager.getCameraResolution();
Point screenResolution = configManager.getScreenResolution();
/* updated to allow for portrait instead of landscape
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; */
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;
framingRectInPreview = rect;
}
return framingRectInPreview;
}
/**
* Allows third party apps to specify the scanning rectangle dimensions, rather than determine
* them automatically based on screen resolution.
*
* @param width The width in pixels to scan.
* @param height The height in pixels to scan.
*/
public void setManualFramingRect(int width, int height) {
Point screenResolution = configManager.getScreenResolution();
if (width > screenResolution.x) {
width = screenResolution.x;
}
if (height > screenResolution.y) {
height = screenResolution.y;
}
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 manual framing rect: " + framingRect);
framingRectInPreview = null;
}
/**
* A factory method to build the appropriate LuminanceSource object based on the format
* of the preview buffers, as described by Camera.Parameters.
*
* @param data A preview frame.
* @param width The width of the image.
* @param height The height of the image.
* @return A PlanarYUVLuminanceSource instance.
*/
public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width, int height) {
Rect rect = getFramingRectInPreview();
int previewFormat = configManager.getPreviewFormat();
String previewFormatString = configManager.getPreviewFormatString();
switch (previewFormat) {
// This is the standard Android format which all devices are REQUIRED to support.
// In theory, it's the only one we should ever care about.
case PixelFormat.YCbCr_420_SP:
// This format has never been seen in the wild, but is compatible as we only care
// about the Y channel, so allow it.
case PixelFormat.YCbCr_422_SP:
return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
rect.width(), rect.height(), reverseImage);
default:
// The Samsung Moment incorrectly uses this variant instead of the 'sp' version.
// Fortunately, it too has all the Y data up front, so we can read it.
if ("yuv420p".equals(previewFormatString)) {
return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
rect.width(), rect.height(), reverseImage);
}
}
throw new IllegalArgumentException("Unsupported picture format: " +
previewFormat + '/' + previewFormatString);
}
}
PreviewCallback.java
final class PreviewCallback implements Camera.PreviewCallback {
private static final String TAG = PreviewCallback.class.getSimpleName();
private final CameraConfigurationManager configManager;
private final boolean useOneShotPreviewCallback;
private Handler previewHandler;
private int previewMessage;
PreviewCallback(CameraConfigurationManager configManager, boolean useOneShotPreviewCallback) {
this.configManager = configManager;
this.useOneShotPreviewCallback = useOneShotPreviewCallback;
}
void setHandler(Handler previewHandler, int previewMessage) {
this.previewHandler = previewHandler;
this.previewMessage = previewMessage;
}
public void onPreviewFrame(byte[] data, Camera camera) {
Point cameraResolution = configManager.getCameraResolution();
if (!useOneShotPreviewCallback) {
camera.setPreviewCallback(null);
}
if (previewHandler != null) {
Message message = previewHandler.obtainMessage(previewMessage, cameraResolution.x,
cameraResolution.y, data);
message.sendToTarget();
previewHandler = null;
} else {
Log.d(TAG, "Got preview callback, but no handler for it");
}
}
}
答案 0 :(得分：3)
在开始预览模式之前，您应该设置相机预览格式。 是的，Android文档说默认格式应为PixelFormat.YCbCr_420_SP = 17，但我看到一些设备不符合此规则。有些人使用 yuyv 打包422格式，它没有要复制的亮度块，就像你的代码一样，但需要重新调整字节。设置预览宽度和高度也是明智之举。您很可能不需要超过VGA分辨率来扫描QR码。
我的设备上的更新：，默认预览帧为1920x1080像素。请注意，这是16：9，而不是4：3的宽高比。我在你的代码中看到了对硬编码4：3的一些引用，但如果用这个假设来解释二维码，那么这就是失败的原因。