问题
This is my source code for barcode snanner which I post again. I edited my code. The problem is, when i run app, flash light is not turned on automatically. I added permission in manifest file, but flash light did not turn on. please help me where is the problem? I am using HTC wIldfire s mobile.
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 Camera camera;
private Rect framingRect;
private Rect framingRectInPreview;
private boolean initialized;
private boolean previewing;
/**
* 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) >
Build.VERSION_CODES.CUPCAKE;
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);
PreferenceManager.getDefaultSharedPreferences(context);
//ÊÇ·ñʹÓÃÇ°µÆ
// if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) {
// FlashlightManager.enableFlashlight();
// }
FlashlightManager.enableFlashlight();
}
}
/**
* Closes the camera driver if still in use.
*/
public void closeDriver() {
if (camera != null) {
FlashlightManager.disableFlashlight();
camera.release();
camera = 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() {
Point screenResolution = configManager.getScreenResolution();
if (framingRect == null) {
if (camera == null) {
return null;
}
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();
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;
}
final class FlashlightManager {
private static final String TAG = FlashlightManager.class.getSimpleName();
private static final Object iHardwareService;
private static final Method setFlashEnabledMethod;
static {
iHardwareService = getHardwareService();
setFlashEnabledMethod = getSetFlashEnabledMethod(iHardwareService);
if (iHardwareService == null) {
Log.v(TAG, "This device does supports control of a flashlight");
} else {
Log.v(TAG, "This device does not support control of a flashlight");
}
}
private FlashlightManager() {
}
private static Object getHardwareService() {
Class<?> serviceManagerClass = maybeForName("android.os.ServiceManager");
if (serviceManagerClass == null) {
return null;
}
Method getServiceMethod = maybeGetMethod(serviceManagerClass, "getService",
String.class);
if (getServiceMethod == null) {
return null;
}
Object hardwareService = invoke(getServiceMethod, null, "hardware");
if (hardwareService == null) {
return null;
}
Class<?> iHardwareServiceStubClass = maybeForName("android.os.IHardwareService$Stub");
if (iHardwareServiceStubClass == null) {
return null;
}
Method asInterfaceMethod = maybeGetMethod(iHardwareServiceStubClass, "asInterface",
IBinder.class);
if (asInterfaceMethod == null) {
return null;
}
return invoke(asInterfaceMethod, null, hardwareService);
}
private static Method getSetFlashEnabledMethod(Object iHardwareService) {
if (iHardwareService == null) {
return null;
}
Class<?> proxyClass = iHardwareService.getClass();
return maybeGetMethod(proxyClass, "setFlashlightEnabled", boolean.class);
}
private static Class<?> maybeForName(String name) {
try {
return Class.forName(name);
} catch (ClassNotFoundException cnfe) {
// OK
return null;
} catch (RuntimeException re) {
Log.w(TAG, "Unexpected error while finding class " + name, re);
return null;
}
}
private static Method maybeGetMethod(Class<?> clazz, String name, Class<?>...
argClasses) {
try {
return clazz.getMethod(name, argClasses);
} catch (NoSuchMethodException nsme) {
// OK
return null;
} catch (RuntimeException re) {
Log.w(TAG, "Unexpected error while finding method " + name, re);
return null;
}
}
private static Object invoke(Method method, Object instance, Object... args) {
try {
return method.invoke(instance, args);
} catch (IllegalAccessException e) {
Log.w(TAG, "Unexpected error while invoking " + method, e);
return null;
} catch (InvocationTargetException e) {
Log.w(TAG, "Unexpected error while invoking " + method, e.getCause());
return null;
} catch (RuntimeException re) {
Log.w(TAG, "Unexpected error while invoking " + method, re);
return null;
}
}
static void enableFlashlight() {
setFlashlight(true);
}
static void disableFlashlight() {
setFlashlight(false);
}
private static void setFlashlight(boolean active) {
if (iHardwareService != null) {
invoke(setFlashEnabledMethod, iHardwareService, active);
}
}
}
package com.zijunlin.Zxing.Demo.camera;
import android.content.Context;
import android.graphics.Point;
import android.hardware.Camera;
import android.os.Build;
import android.util.Log;
import android.view.Display;
import android.view.WindowManager;
import java.util.regex.Pattern;
final class CameraConfigurationManager {
private static final String TAG = CameraConfigurationManager.class.getSimpleName();
private static final int TEN_DESIRED_ZOOM = 27;
private static final int DESIRED_SHARPNESS = 30;
private static final Pattern COMMA_PATTERN = Pattern.compile(",");
private final Context context;
private Point screenResolution;
private Point cameraResolution;
private int previewFormat;
private String previewFormatString;
CameraConfigurationManager(Context context) {
this.context = context;
}
/**
* Reads, one time, values from the camera that are needed by the app.
*/
void initFromCameraParameters(Camera camera) {
Camera.Parameters parameters = camera.getParameters();
previewFormat = parameters.getPreviewFormat();
previewFormatString = parameters.get("preview-format");
Log.d(TAG, "Default preview format: " + previewFormat + '/' + previewFormatString);
WindowManager manager = (WindowManager)
context.getSystemService(Context.WINDOW_SERVICE);
Display display = manager.getDefaultDisplay();
screenResolution = new Point(display.getWidth(), display.getHeight());
Log.d(TAG, "Screen resolution: " + screenResolution);
cameraResolution = getCameraResolution(parameters, screenResolution);
Log.d(TAG, "Camera resolution: " + screenResolution);
}
/**
* Sets the camera up to take preview images which are used for both preview and
decoding.
* We detect the preview format here so that buildLuminanceSource() can build an
appropriate
* LuminanceSource subclass. In the future we may want to force YUV420SP as it's the
smallest,
* and the planar Y can be used for barcode scanning without a copy in some cases.
*/
void setDesiredCameraParameters(Camera camera) {
Camera.Parameters parameters = camera.getParameters();
Log.d(TAG, "Setting preview size: " + cameraResolution);
parameters.setPreviewSize(cameraResolution.x, cameraResolution.y);
setFlash(parameters);
setZoom(parameters);
//setSharpness(parameters);
camera.setParameters(parameters);
}
Point getCameraResolution() {
return cameraResolution;
}
Point getScreenResolution() {
return screenResolution;
}
int getPreviewFormat() {
return previewFormat;
}
String getPreviewFormatString() {
return previewFormatString;
}
private static Point getCameraResolution(Camera.Parameters parameters, Point
screenResolution) {
String previewSizeValueString = parameters.get("preview-size-values");
// saw this on Xperia
if (previewSizeValueString == null) {
previewSizeValueString = parameters.get("preview-size-value");
}
Point cameraResolution = null;
if (previewSizeValueString != null) {
Log.d(TAG, "preview-size-values parameter: " + previewSizeValueString);
cameraResolution = findBestPreviewSizeValue(previewSizeValueString,
screenResolution);
}
if (cameraResolution == null) {
// Ensure that the camera resolution is a multiple of 8, as the screen may not be.
cameraResolution = new Point(
(screenResolution.x >> 3) << 3,
(screenResolution.y >> 3) << 3);
}
return cameraResolution;
}
private static Point findBestPreviewSizeValue(CharSequence previewSizeValueString,
Point screenResolution) {
int bestX = 0;
int bestY = 0;
int diff = Integer.MAX_VALUE;
for (String previewSize : COMMA_PATTERN.split(previewSizeValueString)) {
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);
if (newDiff == 0) {
bestX = newX;
bestY = newY;
break;
} else if (newDiff < diff) {
bestX = newX;
bestY = newY;
diff = newDiff;
}
}
if (bestX > 0 && bestY > 0) {
return new Point(bestX, bestY);
}
return null;
}
private static int findBestMotZoomValue(CharSequence stringValues, int
tenDesiredZoom) {
int tenBestValue = 0;
for (String stringValue : COMMA_PATTERN.split(stringValues)) {
stringValue = stringValue.trim();
double value;
try {
value = Double.parseDouble(stringValue);
} catch (NumberFormatException nfe) {
return tenDesiredZoom;
}
int tenValue = (int) (10.0 * value);
if (Math.abs(tenDesiredZoom - value) < Math.abs(tenDesiredZoom - tenBestValue)) {
tenBestValue = tenValue;
}
}
return tenBestValue;
}
private void setFlash(Camera.Parameters parameters) {
// FIXME: This is a hack to turn the flash off on the Samsung Galaxy.
// And this is a hack-hack to work around a different value on the Behold II
// Restrict Behold II check to Cupcake, per Samsung's advice
//if (Build.MODEL.contains("Behold II") &&
// CameraManager.SDK_INT == Build.VERSION_CODES.CUPCAKE) {
if (Build.MODEL.contains("Behold II") && CameraManager.SDK_INT == 3) { // 3 = Cupcake
parameters.set("flash-value", 1);
} else {
parameters.set("flash-value", 2);
}
// This is the standard setting to turn the flash off that all devices should honor.
parameters.set("flash-mode", "off");
}
private void setZoom(Camera.Parameters parameters) {
String zoomSupportedString = parameters.get("zoom-supported");
if (zoomSupportedString != null && !Boolean.parseBoolean(zoomSupportedString)) {
return;
}
int tenDesiredZoom = TEN_DESIRED_ZOOM;
String maxZoomString = parameters.get("max-zoom");
if (maxZoomString != null) {
try {
int tenMaxZoom = (int) (10.0 * Double.parseDouble(maxZoomString));
if (tenDesiredZoom > tenMaxZoom) {
tenDesiredZoom = tenMaxZoom;
}
} catch (NumberFormatException nfe) {
Log.w(TAG, "Bad max-zoom: " + maxZoomString);
}
}
String takingPictureZoomMaxString = parameters.get("taking-picture-zoom-max");
if (takingPictureZoomMaxString != null) {
try {
int tenMaxZoom = Integer.parseInt(takingPictureZoomMaxString);
if (tenDesiredZoom > tenMaxZoom) {
tenDesiredZoom = tenMaxZoom;
}
} catch (NumberFormatException nfe) {
Log.w(TAG, "Bad taking-picture-zoom-max: " + takingPictureZoomMaxString);
}
}
String motZoomValuesString = parameters.get("mot-zoom-values");
if (motZoomValuesString != null) {
tenDesiredZoom = findBestMotZoomValue(motZoomValuesString, tenDesiredZoom);
}
String motZoomStepString = parameters.get("mot-zoom-step");
if (motZoomStepString != null) {
try {
double motZoomStep = Double.parseDouble(motZoomStepString.trim());
int tenZoomStep = (int) (10.0 * motZoomStep);
if (tenZoomStep > 1) {
tenDesiredZoom -= tenDesiredZoom % tenZoomStep;
}
} catch (NumberFormatException nfe) {
// continue
}
}
// Set zoom. This helps encourage the user to pull back.
// Some devices like the Behold have a zoom parameter
if (maxZoomString != null || motZoomValuesString != null) {
parameters.set("zoom", String.valueOf(tenDesiredZoom / 10.0));
}
// Most devices, like the Hero, appear to expose this zoom parameter.
// It takes on values like "27" which appears to mean 2.7x zoom
if (takingPictureZoomMaxString != null) {
parameters.set("taking-picture-zoom", tenDesiredZoom);
}
}
/*
private void setSharpness(Camera.Parameters parameters) {
int desiredSharpness = DESIRED_SHARPNESS;
String maxSharpnessString = parameters.get("sharpness-max");
if (maxSharpnessString != null) {
try {
int maxSharpness = Integer.parseInt(maxSharpnessString);
if (desiredSharpness > maxSharpness) {
desiredSharpness = maxSharpness;
}
} catch (NumberFormatException nfe) {
Log.w(TAG, "Bad sharpness-max: " + maxSharpnessString);
}
}
parameters.set("sharpness", desiredSharpness);
}
*/
}
<uses-permission android:name="android.permission.CAMERA"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-
permission>
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-permission android:name="android.permission.VIBRATE"/>
<uses-permission android:name="android.permission.FLASHLIGHT"/>
<uses-permission android:name="android.permission.INTERNET" />
回答1:
you can see simple flashlight operations in the example working code here: https://bitbucket.org/hqureshi/yafa its simple open source flashlight app for android.
来源：https://stackoverflow.com/questions/13342210/flash-light-is-not-turned-on