Android振动器 android.os.Vibrator
1.Java层 frameworks/base/core/java/android/os/Vibrator.java
Vibrator类的实力可以通过 getSystemService(VIBRATOR_SERVICE)获得实例。
两个方法:public abstract void vibrate(long milliseconds);/public abstract void vibrate(long[] pattern, int repeat); public abstract void cancel(); 查找路径:Activity.java-->ContextThemeWrapper.java-->ContextWrapper.java-->Context.java,getSystemService是Context.java类的抽象方法。其实现的类是ContextImpl.java,其中有段静态代码,注册所有context下能使用到的service。registerService(VIBRATOR_SERVICE, new ServiceFetcher() { public Object createService(ContextImpl ctx) { return new SystemVibrator(); }});
Vibrator类只是个抽象类,具体实现的代码位于 SystemVibrator。位于\frameworks\base\core\java\android\os\目录下。两个方法的实现代码如下:
@Override public void vibrate(long milliseconds) { if (mService == null) { Log.w(TAG, "Failed to vibrate; no vibrator service."); return; } try { mService.vibrate(milliseconds, mToken); } catch (RemoteException e) { Log.w(TAG, "Failed to vibrate.", e); } }
与
@Override public void vibrate(long[] pattern, int repeat) { if (mService == null) { Log.w(TAG, "Failed to vibrate; no vibrator service."); return; } // catch this here because the server will do nothing. pattern may // not be null, let that be checked, because the server will drop it // anyway if (repeat < pattern.length) { try { mService.vibratePattern(pattern, repeat, mToken); } catch (RemoteException e) { Log.w(TAG, "Failed to vibrate.", e); } } else { throw new ArrayIndexOutOfBoundsException(); } }
还有
@Override public void cancel() { if (mService == null) { return; } try { mService.cancelVibrate(mToken); } catch (RemoteException e) { Log.w(TAG, "Failed to cancel vibration.", e); } }
查看mService,其声明代码如下:
mService = IVibratorService.Stub.asInterface( ServiceManager.getService("vibrator"));
/*这里跟Binder机制有关。。。断片ing*/
定义是private final IVibratorService mService;
所以找找这个IVibratorService吧。 查找下\frameworks\base\core\java\android\os\IVibratorService.aidl,这里定义了接口。package android.os;/** {@hide} */interface IVibratorService{ boolean hasVibrator(); void vibrate(long milliseconds, IBinder token); void vibratePattern(in long[] pattern, int repeat, IBinder token); void cancelVibrate(IBinder token);}
具体的实现位于VibratorService.java。(\frameworks\base\services\java\com\android\server\)
public class VibratorService extends IVibratorService.Stub然后是vibrate方法:
public void vibrate(long milliseconds, IBinder token) { if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.VIBRATE) != PackageManager.PERMISSION_GRANTED) { throw new SecurityException("Requires VIBRATE permission"); } int uid = Binder.getCallingUid(); // We're running in the system server so we cannot crash. Check for a // timeout of 0 or negative. This will ensure that a vibration has // either a timeout of > 0 or a non-null pattern. if (milliseconds <= 0 || (mCurrentVibration != null && mCurrentVibration.hasLongerTimeout(milliseconds))) { // Ignore this vibration since the current vibration will play for // longer than milliseconds. return; } Vibration vib = new Vibration(token, milliseconds, uid); synchronized (mVibrations) { removeVibrationLocked(token); doCancelVibrateLocked(); mCurrentVibration = vib; startVibrationLocked(vib); } }然后是startVibrationLocked方法。
private void startVibrationLocked(final Vibration vib) { if (vib.mTimeout != 0) { doVibratorOn(vib.mTimeout); mH.postDelayed(mVibrationRunnable, vib.mTimeout); } else { // mThread better be null here. doCancelVibrate should always be // called before startNextVibrationLocked or startVibrationLocked. mThread = new VibrateThread(vib); mThread.start(); } }翻看了VibrateThread的run方法,最终还是调用了doVibratorOn方法。 所以看doVibratorOn方法:
private void doVibratorOn(long millis) { synchronized (mInputDeviceVibrators) { final int vibratorCount = mInputDeviceVibrators.size(); if (vibratorCount != 0) { for (int i = 0; i < vibratorCount; i++) { mInputDeviceVibrators.get(i).vibrate(millis); } } else { vibratorOn(millis); } } }|---------首先是vibratorCount这个,假如这个不为0,那么是调用 Vibrator的vibrate方法。。断片:vibratorCount这个表示什么意义! mInputDeviceVibrators的声明如下:
private final ArrayList里面的每一个元素都是一个Vibrator的实力,Vibrator是个抽闲类。 mInputDeviceVibrators会在VibratorService.java中的updateInputDeviceVibrators方法添加元素:mInputDeviceVibrators = new ArrayList ();
mInputDeviceVibrators.clear();if (mVibrateInputDevicesSetting) { int[] ids = mIm.getInputDeviceIds(); for (int i = 0; i < ids.length; i++) { InputDevice device = mIm.getInputDevice(ids[i]); Vibrator vibrator = device.getVibrator(); if (vibrator.hasVibrator()) { mInputDeviceVibrators.add(vibrator); } }}查看InputDevice类的getVibrator
public Vibrator getVibrator() { synchronized (mMotionRanges) { if (mVibrator == null) { if (mHasVibrator) { mVibrator = InputManager.getInstance().getInputDeviceVibrator(mId); } else { mVibrator = NullVibrator.getInstance(); } } return mVibrator; } }所以数组 mInputDeviceVibrators中的元素有两种,都是抽象类Vibrator的子类: 一种是InputDeviceVibrator类,一种就是NullVibrator类了。 先说说InputDeviceVibrator类。
private final class InputDeviceVibrator extends Vibrator { private final int mDeviceId; private final Binder mToken; public InputDeviceVibrator(int deviceId) { mDeviceId = deviceId; mToken = new Binder(); } @Override public boolean hasVibrator() { return true; } @Override public void vibrate(long milliseconds) { vibrate(new long[] { 0, milliseconds}, -1); } @Override public void vibrate(long[] pattern, int repeat) { if (repeat >= pattern.length) { throw new ArrayIndexOutOfBoundsException(); } try { mIm.vibrate(mDeviceId, pattern, repeat, mToken); } catch (RemoteException ex) { Log.w(TAG, "Failed to vibrate.", ex); } } @Override public void cancel() { try { mIm.cancelVibrate(mDeviceId, mToken); } catch (RemoteException ex) { Log.w(TAG, "Failed to cancel vibration.", ex); } } }这里关注public void vibrate(long[] pattern, int repeat)方法,最终调用mIm.vibrate(mDeviceId, pattern, repeat, mToken)。。坑爹的,mIm是个抽象类,又得去找其实例,然后穿越到InputManagerService.java,放看起vibrate方法:
public void vibrate(int deviceId, long[] pattern, int repeat, IBinder token) { if (repeat >= pattern.length) { throw new ArrayIndexOutOfBoundsException(); } VibratorToken v; synchronized (mVibratorLock) { v = mVibratorTokens.get(token); if (v == null) { v = new VibratorToken(deviceId, token, mNextVibratorTokenValue++); try { token.linkToDeath(v, 0); } catch (RemoteException ex) { // give up throw new RuntimeException(ex); } mVibratorTokens.put(token, v); } } synchronized (v) { v.mVibrating = true; nativeVibrate(mPtr, deviceId, pattern, repeat, v.mTokenValue); } }这里调用了JNI方法nativeVibrate,同样,InputDeviceVibrator的cancel方法也到了这里:
public void cancelVibrate(int deviceId, IBinder token) { VibratorToken v; synchronized (mVibratorLock) { v = mVibratorTokens.get(token); if (v == null || v.mDeviceId != deviceId) { return; // nothing to cancel } } cancelVibrateIfNeeded(v); }cancelVibrateIfNeeded方法最终调用nativeCancelVibrate方法。到达JNI层。 ||||||||| 再来看看NullVibrator类。。不过既然是Null。。。那就是Null实现。 自此,vibrate跟cancel到达的JNI层的接口是:
private static native void nativeVibrate(int ptr, int deviceId, long[] pattern, int repeat, int token); private static native void nativeCancelVibrate(int ptr, int deviceId, int token);|-------然后是vibratorCount为0的情况,直接调用vibratorOn,cancel同理。 自此,vibrate跟cancel到达的JNI层的接口是:
native static void vibratorOn(long milliseconds); native static void vibratorOff();
2.JNI层 --对于nativeVibrate/nativeCancelVibrate,其实现位于com_android_server_input_InputManagerService.cpp中.
static void nativeVibrate(JNIEnv* env, jclass clazz, jint ptr, jint deviceId, jlongArray patternObj, jint repeat, jint token) { NativeInputManager* im = reinterpret_cast-- 对于vibratorOn /vibratorOff,其实现位于com_android_server_VibratorService.cpp中(ptr); size_t patternSize = env->GetArrayLength(patternObj); if (patternSize > MAX_VIBRATE_PATTERN_SIZE) { ALOGI("Skipped requested vibration because the pattern size is %d " "which is more than the maximum supported size of %d.", patternSize, MAX_VIBRATE_PATTERN_SIZE); return; // limit to reasonable size } jlong* patternMillis = static_cast (env->GetPrimitiveArrayCritical( patternObj, NULL)); nsecs_t pattern[patternSize]; for (size_t i = 0; i < patternSize; i++) { pattern[i] = max(jlong(0), min(patternMillis[i], MAX_VIBRATE_PATTERN_DELAY_NSECS / 1000000LL)) * 1000000LL; } env->ReleasePrimitiveArrayCritical(patternObj, patternMillis, JNI_ABORT); im->getInputManager()->getReader()->vibrate(deviceId, pattern, patternSize, repeat, token);}static void nativeCancelVibrate(JNIEnv* env, jclass clazz, jint ptr, jint deviceId, jint token) { NativeInputManager* im = reinterpret_cast (ptr); im->getInputManager()->getReader()->cancelVibrate(deviceId, token);}
static JNINativeMethod method_table[] = { { "vibratorExists", "()Z", (void*)vibratorExists }, { "vibratorOn", "(J)V", (void*)vibratorOn }, { "vibratorOff", "()V", (void*)vibratorOff }};
static void vibratorOn(JNIEnv *env, jobject clazz, jlong timeout_ms){ // ALOGI("vibratorOn\n"); vibrator_on(timeout_ms);}static void vibratorOff(JNIEnv *env, jobject clazz){ // ALOGI("vibratorOff\n"); vibrator_off();}3.HAL层 vib rator_on/vibrator_off的定义位于头文件<hardware_legacy/vibrator.h>(\hardware\libhardware_legacy\include\hardware_legacy\)
/** * Turn on vibrator * * @param timeout_ms number of milliseconds to vibrate * * @return 0 if successful, -1 if error */int vibrator_on(int timeout_ms);/** * Turn off vibrator * * @return 0 if successful, -1 if error */int vibrator_off();HAL已经完成了实现。 \hardware\libhardware_legacy\vibrator\vibrator.c
/* * Copyright (C) 2008 The Android Open Source Project * * 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. */#include#include "qemu.h"#include #include #include #include #define THE_DEVICE "/sys/class/timed_output/vibrator/enable"int vibrator_exists(){ int fd;#ifdef QEMU_HARDWARE if (qemu_check()) { return 1; }#endif fd = open(THE_DEVICE, O_RDWR); if(fd < 0) return 0; close(fd); return 1;}static int sendit(int timeout_ms){ int nwr, ret, fd; char value[20];#ifdef QEMU_HARDWARE if (qemu_check()) { return qemu_control_command( "vibrator:%d", timeout_ms ); }#endif fd = open(THE_DEVICE, O_RDWR); if(fd < 0) return errno; nwr = sprintf(value, "%d\n", timeout_ms); ret = write(fd, value, nwr); close(fd); return (ret == nwr) ? 0 : -1;}int vibrator_on(int timeout_ms){ /* constant on, up to maximum allowed time */ return sendit(timeout_ms);}int vibrator_off(){ return sendit(0);}
这里使用的是Android的timed output机制,通过操纵/sys/class/timed_output/vibrator/enable节点启动或者停止启动器。
4.内核层 先看看timed output的驱动代码,位于Linux_Kernel_3x\drivers\staging\android\下。#ifndef _LINUX_TIMED_OUTPUT_H#define _LINUX_TIMED_OUTPUT_Hstruct timed_output_dev { const char *name; /* enable the output and set the timer */ void (*enable)(struct timed_output_dev *sdev, int timeout); /* returns the current number of milliseconds remaining on the timer */ int (*get_time)(struct timed_output_dev *sdev); /* private data */ struct device *dev; int index; int state;};extern int timed_output_dev_register(struct timed_output_dev *dev);extern void timed_output_dev_unregister(struct timed_output_dev *dev);#endif
所有的timed output实现都需要定义在结构体timed_output_dev中。
Timed Output驱动程序框架将为每个设备在/sys/class/timed_output/目录中建立一个子目录,设备子目录中的enable文件就是设备的控制文件。读enable文件表示获得剩余时间,写这个文件表示根据时间振动。 这个具体情况具体实现,参考: