/* * Copyright (C) 2010 ZXing authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.fanxin.huangfangyi.main.widget.zxing.camera; import android.os.IBinder; import android.util.Log; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; /** * This class is used to activate the weak light on some camera phones (not flash) * in order to illuminate surfaces for scanning. There is no official way to do this, * but, classes which allow access to this function still exist on some devices. * This therefore proceeds through a great deal of reflection. * * See <a href="http://almondmendoza.com/2009/01/05/changing-the-screen-brightness-programatically/"> * http://almondmendoza.com/2009/01/05/changing-the-screen-brightness-programatically/</a> and * <a href="http://code.google.com/p/droidled/source/browse/trunk/src/com/droidled/demo/DroidLED.java"> * http://code.google.com/p/droidled/source/browse/trunk/src/com/droidled/demo/DroidLED.java</a>. * Thanks to Ryan Alford for pointing out the availability of this class. */ 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() { } //FIXME static void enableFlashlight() { setFlashlight(false); } static void disableFlashlight() { setFlashlight(false); } 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; } } private static void setFlashlight(boolean active) { if (iHardwareService != null) { invoke(setFlashEnabledMethod, iHardwareService, active); } } }