8种机械键盘轴体对比

本人程序员，要买一个写代码的键盘，请问红轴和茶轴怎么选？

一、SystemUI组成

SystemUI是Android的系统界面，包括状态栏statusbar、锁屏keyboard、任务列表recents等等，都继承于SystemUI这个类，如锁屏KeyguardViewMediator。

二、SystemUI启动流程

SystemUI的启动由SystemServer开始。SystemServer由Zygote fork生成的，进程名为system_server，该进程承载着framework的核心服务。Zygote启动过程中会调用startSystemServer()。SystemUI的分析从SystemServer的main方法开始。SystemUI启动的大致流程如下：

2.1 SystemServer

SystemServer在run方法中负责启动系统的各种服务。

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15..........

// Start services.

try {

traceBeginAndSlog("StartServices");

startBootstrapServices();

startCoreServices();

startOtherServices();

SystemServerInitThreadPool.shutdown();

} catch (Throwable ex) {

Slog.e("System", "******************************************");

Slog.e("System", "************ Failure starting system services", ex);

throw ex;

} finally {

traceEnd();

}

在startOtherServices方法中先是创建并添加WindowManagerService、InputManagerService等service,并且调用startSystemUi方法，跳转SystemUIService。

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25private void startOtherServices() {

//创建，注册服务

...

WindowManagerService wm = null;

SerialService serial = null;

NetworkTimeUpdateService networkTimeUpdater = null;

CommonTimeManagementService commonTimeMgmtService = null;

InputManagerService inputManager = null;

...

traceBeginAndSlog("IpConnectivityMetrics");

mSystemServiceManager.startService(IpConnectivityMetrics.class);

traceEnd();

traceBeginAndSlog("NetworkWatchlistService");

mSystemServiceManager.startService(NetworkWatchlistService.Lifecycle.class);

traceEnd();

...

traceBeginAndSlog("StartSystemUI");

try {

startSystemUi(context, windowManagerF);

} catch (Throwable e) {

reportWtf("starting System UI", e);

}

启动跳转SystemUIService。

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9static final void startSystemUi(Context context, WindowManagerService windowManager) {

Intent intent = new Intent();

intent.setComponent(new ComponentName("com.android.systemui",

"com.android.systemui.SystemUIService"));

intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING);

//Slog.d(TAG, "Starting service: " + intent);

context.startServiceAsUser(intent, UserHandle.SYSTEM);

windowManager.onSystemUiStarted();

}

2.2 SystemUIService

SystemUIService在onCreate中调用SystemUIApplication的startServicesIfNeeded方法。

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12@Override

public void onCreate() {

super.onCreate();

((SystemUIApplication) getApplication()).startServicesIfNeeded();

// For debugging RescueParty

if (Build.IS_DEBUGGABLE && SystemProperties.getBoolean("debug.crash_sysui", false)) {

throw new RuntimeException();

}

...

}

2.3 SystemUIApplication

SystemUIApplication先获取配置的systemUI组件。

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4public void startServicesIfNeeded() {

String[] names = getResources().getStringArray(R.array.config_systemUIServiceComponents);

startServicesIfNeeded(names);

}

配置文件在/frameworks/base/packages/SystemUI/res/values/config.xml中，配置的systemui组件如图：

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332 com.android.systemui.Dependency

333 com.android.systemui.util.NotificationChannels

334 com.android.systemui.statusbar.CommandQueue$CommandQueueStart

335 com.android.systemui.keyguard.KeyguardViewMediator

336 com.android.systemui.recents.Recents

337 com.android.systemui.volume.VolumeUI

338 com.android.systemui.stackdivider.Divider

339 com.android.systemui.SystemBars

340 com.android.systemui.usb.StorageNotification

341 com.android.systemui.power.PowerUI

342 com.android.systemui.media.RingtonePlayer

343 com.android.systemui.keyboard.KeyboardUI

344 com.android.systemui.pip.PipUI

345 com.android.systemui.shortcut.ShortcutKeyDispatcher

346 @string/config_systemUIVendorServiceComponent

347 com.android.systemui.util.leak.GarbageMonitor$Service

348 com.android.systemui.LatencyTester

349 com.android.systemui.globalactions.GlobalActionsComponent

350 com.android.systemui.ScreenDecorations

351 com.android.systemui.fingerprint.FingerprintDialogImpl

352 com.android.systemui.SliceBroadcastRelayHandler

353

在startServicesIfNeeded方法中，根据config配置创建SystemUI，并调用SystemUI的start方法。

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31private void startServicesIfNeeded(String[] services) {

if (mServicesStarted) {

return;

}

mServices = new SystemUI[services.length];

final int N = services.length;

for (int i = 0; i < N; i++) {

String clsName = services[i];

if (DEBUG) Log.d(TAG, "loading: " + clsName);

log.traceBegin("StartServices" + clsName);

long ti = System.currentTimeMillis();

Class cls;

try {

cls = Class.forName(clsName);

mServices[i] = (SystemUI) cls.newInstance();

} catch(ClassNotFoundException ex){

throw new RuntimeException(ex);

} catch (IllegalAccessException ex) {

throw new RuntimeException(ex);

} catch (InstantiationException ex) {

throw new RuntimeException(ex);

}

mServices[i].mContext = this;

mServices[i].mComponents = mComponents;

if (DEBUG) Log.d(TAG, "running: " + mServices[i]);

mServices[i].start();

log.traceEnd();

...

}

2.4 SystemUI

SystemUI是一个抽象类，start()是抽象方法，具体实现在子类。

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16public abstract class SystemUI implements SysUiServiceProvider {

public Context mContext;

public Map, Object> mComponents;

public abstract void start();

protected void onConfigurationChanged(Configuration newConfig) {

}

public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {

}

protected void onBootCompleted() {

}

...

}