电子商务网站策划书布局设计,网站布局优化怎么做,建设网站的建设费用包括什么科目,长春开发公司这一节主要了解一下Android输入事件源码#xff0c;Android输入系统的工作原理概括来说#xff0c;就是监控/dev/input/下的所有设备节点#xff0c;当某个节点有数据可读时#xff0c;将数据读出并进行一系列的加工#xff0c;然后在所有的窗口中寻找合适的事件接收者Android输入系统的工作原理概括来说就是监控/dev/input/下的所有设备节点当某个节点有数据可读时将数据读出并进行一系列的加工然后在所有的窗口中寻找合适的事件接收者并派发给它。 整体含有几个关键因素:
Linux内核:接受输入设备的中断并将原始事件的数据写入设备节点中。
设备节点:作为内核与IMS的桥梁它将原始事件的数据暴露给用户空间以便IMS可以从中读取事件。
EventHub:直接访问所有的设备节点。并且正如其名字所描述的它通过一个名为getEvents()的函数将所有输入系统相关的待处理的底层事件返回给使用者。这些事件包括原始输入事件、设备节点的增删等。
InputReader是IMS中的关键组件之一。它运行于一个独立的线程中负责管理输入设备的列表与配置以及进行输入事件的加工处理。它通过其线程循环不断地通过getEventsO)函数从EventHub 中将事件取出并进行处理。对于设备节点的增删事件它会更新输入设备列表与配置。对于原始输入事件InputReader对其进行翻译、组装、封装为包含更多信息、更具可读性的输人事件然后交给 InputDispatcher 进行派发。
InputReaderPolicy:它为InputReader的事件加工处理提供一些策略配置例如键盘布局信息等。
InputDispatcher:是IMS中的另一个关键组件。它也运行于一个独立的线程中。InputDispatcher中保管了来自WMS的所有窗口的信息其收到来自InputReader的输入事件后会在其保管的窗口中寻找合适的窗口并将事件派发给此窗口。
InputDispatcherPolicy:它为InputDispatcher的派发过程提供策略控制。例如截取某些特定的输入事件用作特殊用途或者阻止将某些事件派发给目标窗口。一个典型的例子就是HOME键被InputDispatcherPolicy截取到PhoneWindowManager中进行处理并阻止窗口收到HOME键按下的事件。
WMS:虽说不是输入系统中的一员但是它却对InputDispatcher的正常工作起到了至关重要的作用。当新建窗口时WMS为新窗口和IMS创建了事件传递所用的通道。另外WMS还将所有窗口的信息包括窗口的可点击区域、焦点窗口等信息实时地更新到IMS的InputDispatcher 中使得InputDispatcher 可以正确地将事件派发到指定的窗口。
ViewRootImpl:对某些窗口如壁纸窗口、SurfaceView的窗口来说窗口就是输入事件派发的终点。而对其他的如Activity、对话框等使用了Android 控件系统的窗口来说输入事件的终点是控件View)。ViewRootImpl将窗口所接收的输人事件沿着控件树将事件派发给感兴趣的控件。
frameworks/base/services/java/com/android/server/SystemServer.javapublic static void main(String[] args) {new SystemServer().run();}private void run() {TimingsTraceAndSlog t new TimingsTraceAndSlog();try {t.traceBegin(InitBeforeStartServices);// Record the process start information in sys props.SystemProperties.set(SYSPROP_START_COUNT, String.valueOf(mStartCount));SystemProperties.set(SYSPROP_START_ELAPSED, String.valueOf(mRuntimeStartElapsedTime));SystemProperties.set(SYSPROP_START_UPTIME, String.valueOf(mRuntimeStartUptime));EventLog.writeEvent(EventLogTags.SYSTEM_SERVER_START,mStartCount, mRuntimeStartUptime, mRuntimeStartElapsedTime); // The system server should never make non-oneway callsBinder.setWarnOnBlocking(true);// The system server should always load safe labelsPackageItemInfo.forceSafeLabels();// Default to FULL within the system server.SQLiteGlobal.sDefaultSyncMode SQLiteGlobal.SYNC_MODE_FULL;// Deactivate SQLiteCompatibilityWalFlags until settings provider is initializedSQLiteCompatibilityWalFlags.init(null);// Here we go!Slog.i(TAG, Entered the Android system server!);final long uptimeMillis SystemClock.elapsedRealtime();EventLog.writeEvent(EventLogTags.BOOT_PROGRESS_SYSTEM_RUN, uptimeMillis);if (!mRuntimeRestart) {FrameworkStatsLog.write(FrameworkStatsLog.BOOT_TIME_EVENT_ELAPSED_TIME_REPORTED,FrameworkStatsLog.BOOT_TIME_EVENT_ELAPSED_TIME__EVENT__SYSTEM_SERVER_INIT_START,uptimeMillis);}SystemProperties.set(persist.sys.dalvik.vm.lib.2, VMRuntime.getRuntime().vmLibrary());// Mmmmmm... more memory!VMRuntime.getRuntime().clearGrowthLimit();// Some devices rely on runtime fingerprint generation, so make sure// weve defined it before booting further.Build.ensureFingerprintProperty();// Create the system service manager.mSystemServiceManager new SystemServiceManager(mSystemContext);mSystemServiceManager.setStartInfo(mRuntimeRestart,mRuntimeStartElapsedTime, mRuntimeStartUptime);LocalServices.addService(SystemServiceManager.class, mSystemServiceManager);// Prepare the thread pool for init tasks that can be parallelizedSystemServerInitThreadPool.start();// Attach JVMTI agent if this is a debuggable build and the system property is set....} finally {t.traceEnd(); // InitBeforeStartServices}// Setup the default WTF handlerRuntimeInit.setDefaultApplicationWtfHandler(SystemServer::handleEarlySystemWtf);// Start services.try {t.traceBegin(StartServices);// 启动引导服务startBootstrapServices(t);// 启动核心服务startCoreServices(t);// 启动其他服务 startOtherServices(t);} catch (Throwable ex) {Slog.e(System, ******************************************);Slog.e(System, ************ Failure starting system services, ex);throw ex;} finally {t.traceEnd(); // StartServices}StrictMode.initVmDefaults(null);...// Diagnostic to ensure that the system is in a base healthy state. Done here as a common// non-zygote process.if (!VMRuntime.hasBootImageSpaces()) {Slog.wtf(TAG, Runtime is not running with a boot image!);}// Loop forever.Looper.loop();throw new RuntimeException(Main thread loop unexpectedly exited);}private void startOtherServices(NonNull TimingsTraceAndSlog t) {final Context context mSystemContext;VibratorService vibrator null;DynamicSystemService dynamicSystem null;IStorageManager storageManager null;NetworkManagementService networkManagement null;IpSecService ipSecService null;NetworkStatsService networkStats null;NetworkPolicyManagerService networkPolicy null;ConnectivityService connectivity null;NsdService serviceDiscovery null;WindowManagerService wm null;SerialService serial null;NetworkTimeUpdateService networkTimeUpdater null;InputManagerService inputManager null;TelephonyRegistry telephonyRegistry null;ConsumerIrService consumerIr null;MmsServiceBroker mmsService null;HardwarePropertiesManagerService hardwarePropertiesService null;try {t.traceBegin(StartInputManagerService);inputManager new InputManagerService(context);wm WindowManagerService.main(context, inputManager, !mFirstBoot, mOnlyCore,new PhoneWindowManager(), mActivityManagerService.mActivityTaskManager);inputManager.setWindowManagerCallbacks(wm.getInputManagerCallback());inputManager.start(); } catch (Throwable e) {Slog.e(System, ******************************************);Slog.e(System, ************ Failure starting core service);throw e;} }
/frameworks/base/services/core/java/com/android/server/input/InputManagerService.javapublic void start() {Slog.i(TAG, Starting input manager);nativeStart(mPtr);// Add ourself to the Watchdog monitors.Watchdog.getInstance().addMonitor(this);registerPointerSpeedSettingObserver();registerShowTouchesSettingObserver();registerAccessibilityLargePointerSettingObserver();registerLongPressTimeoutObserver();mContext.registerReceiver(new BroadcastReceiver() {Overridepublic void onReceive(Context context, Intent intent) {updatePointerSpeedFromSettings();updateShowTouchesFromSettings();updateAccessibilityLargePointerFromSettings();updateDeepPressStatusFromSettings(user switched);}}, new IntentFilter(Intent.ACTION_USER_SWITCHED), null, mHandler);updatePointerSpeedFromSettings();updateShowTouchesFromSettings();updateAccessibilityLargePointerFromSettings();updateDeepPressStatusFromSettings(just booted);}
/frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cppstatic void nativeStart(JNIEnv* env, jclass /* clazz */, jlong ptr) {NativeInputManager* im reinterpret_castNativeInputManager*(ptr);status_t result im-getInputManager()-start();if (result) {jniThrowRuntimeException(env, Input manager could not be started.);}}inline spInputManager getInputManager() const { return mInputManager; }
用reinterpret_cast操作符将jlong类型的ptr强制转换为原类型NativeInputManager指针类型。 /frameworks/native/services/inputflinger/InputManager.cppstatus_t InputManager::start() {status_t result mDispatcher-start();if (result) {ALOGE(Could not start InputDispatcher thread due to error %d., result);return result;}result mReader-start();if (result) {ALOGE(Could not start InputReader due to error %d., result);mDispatcher-stop();return result;}return OK;
}
/frameworks/native/services/inputflinger/reader/InputReaderFactory.cppnamespace android {spInputReaderInterface createInputReader(const spInputReaderPolicyInterface policy,const spInputListenerInterface listener) {return new InputReader(std::make_uniqueEventHub(), policy, listener);
}} // namespace android/frameworks/native/services/inputflinger/reader/InputReader.cppstatus_t InputReader::start() {if (mThread) {return ALREADY_EXISTS;}mThread std::make_uniqueInputThread(InputReader, [this]() { loopOnce(); }, [this]() { mEventHub-wake(); });return OK;
}
/frameworks/native/services/inputflinger/InputThread.cppclass InputThreadImpl : public Thread {
public:explicit InputThreadImpl(std::functionvoid() loop): Thread(/* canCallJava */ true), mThreadLoop(loop) {}~InputThreadImpl() {}private:std::functionvoid() mThreadLoop;bool threadLoop() override {mThreadLoop();return true;}
};
InputManager的start函数运行了InputDispatcherThread和InputReaderThread线程
InputDispatcher和InputReader是在哪创建的
/frameworks/native/services/inputflinger/InputManager.cppInputManager::InputManager(const spInputReaderPolicyInterface readerPolicy,const spInputDispatcherPolicyInterface dispatcherPolicy) {mDispatcher createInputDispatcher(dispatcherPolicy);mClassifier new InputClassifier(mDispatcher);mReader createInputReader(readerPolicy, mClassifier);
}
可以看出InputDispatcher和InputReader是有关联的InputDispatcher会作为一个参数传入到InputReader中;
