浅析android锁屏开机绘制流程（基于android4.0源码分析）

最近大体看了一下android源码锁屏模块，顺便把自己的收获在此记录下来，希望对研究锁屏的同行们有所帮助（对于锁屏模块，本人也没什么时间去真正的深究，只是摸清了个大概，若有奇异和错误之处，恳请指出）

好了，废话不多说了。

Android源码模块锁屏大体分为两种：

1.LockScreen: 系统默认的锁屏，就是我们所常见的系统原生波纹解锁(涉及MultiWaveView视图类)。如下图：



2.UnlockScreen: 进入手机的设置----->安全----->屏幕锁定。在列表中将看到的可选择项：图案，PIN，密码等锁屏都归为UnlockScreen。（可选择任意一项切换锁屏）

锁屏相关源码所在路径：

1.锁屏模块的框架源码所在路径为：frameworks\base\policy\src\com\android\internal\policy\impl（本文所涉及的代码都在这个目录里）

2.相关的锁屏自定义View类及与其关联类的源码所在路径为：frameworks\base\core\java\com\android\internal\widget

开机绘制锁屏流程代码分析：

手机开机时，在SystemServer类的init2()方法中会启动线程类ServerThread的run方法如下：

class ServerThread extends Thread
{

@Override
public void run()
{
WindowManagerService wm = null;
...
try
{
wm.systemReady();
} catch (Throwable e)
{
reportWtf("making Window Manager Service ready", e);
}
...
}
}

------>上述代码中的wm为WindowManagerService的引用，所以，wm.systemReady()为调用WindowManagerService的systemReady()方法，如下代码：

public class WindowManagerService extends IWindowManager.Stub implements Watchdog.Monitor, WindowManagerPolicy.WindowManagerFuncs
{
final WindowManagerPolicy mPolicy = PolicyManager.makeNewWindowManager();
...
public void systemReady() {
mPolicy.systemReady();
}
...
}

------>WindowManagerPolicy的实现类为PhoneWindowManager，所以，接着调用到PhoneWindowManager的systemReady，如下：

public class PhoneWindowManager implements WindowManagerPolicy
{
KeyguardViewMediator mKeyguardMediator;
...
//手机开机后执行
public void systemReady() {
// tell the keyguard
mKeyguardMediator.onSystemReady(); //进行待机锁屏及解锁逻辑
android.os.SystemProperties.set("dev.bootcomplete", "1");
synchronized (mLock) {
updateOrientationListenerLp();
mSystemReady = true;
mHandler.post(new Runnable() {
public void run() {
updateSettings();
}
});
}
}
...
}

------>接着，调用到KeyguardViewMediator类的onSystemReady()方法如下：

public class KeyguardViewMediator implements KeyguardViewCallback,
KeyguardUpdateMonitor.InfoCallback, KeyguardUpdateMonitor.SimStateCallback
{
...
/**
* Let us know that the system is ready after startup.
*/
//开机显示锁屏入口
public void onSystemReady() {
synchronized (this) {
if (DEBUG) Log.d(TAG, "onSystemReady");
mSystemReady = true;
doKeyguardLocked();
}
}
...
}

------>调用KeyguardViewMediator.doKeyguardLocked方法，在该方法中，先执行一些条件判断，若满足直接返回。若不直接返回，则紧接着调用KeyguardViewMediator. showLocked方法，代码如下：

...
/**
* Send message to keyguard telling it to show itself
* @see #handleShow()
*/
private void showLocked() {
if (DEBUG) Log.d(TAG, "showLocked");
// ensure we stay awake until we are finished displaying the keyguard
mShowKeyguardWakeLock.acquire(); //确保屏幕处于唤醒状态
Message msg = mHandler.obtainMessage(SHOW);
mHandler.sendMessage(msg);
}
...

----->通过handler发送消息SHOW到handleMessage处理，如下：

...
/**
* This handler will be associated with the policy thread, which will also
* be the UI thread of the keyguard.  Since the apis of the policy, and therefore
* this class, can be called by other threads, any action that directly
* interacts with the keyguard ui should be posted to this handler, rather
* than called directly.
*/
//Handler对象 ， 异步处理
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) { //异步处理
switch (msg.what) {
case TIMEOUT:
handleTimeout(msg.arg1);
return ;
case SHOW:
handleShow();
return ;
case HIDE:
handleHide();
return ;
case RESET:
handleReset();
return ;
case VERIFY_UNLOCK:
handleVerifyUnlock();
return;
case NOTIFY_SCREEN_OFF:
handleNotifyScreenOff();
return;
case NOTIFY_SCREEN_ON:
handleNotifyScreenOn((KeyguardViewManager.ShowListener)msg.obj);
return;
case WAKE_WHEN_READY:
handleWakeWhenReady(msg.arg1);
return;
case KEYGUARD_DONE:
handleKeyguardDone(msg.arg1 != 0);
return;
case KEYGUARD_DONE_DRAWING:
handleKeyguardDoneDrawing();
return;
case KEYGUARD_DONE_AUTHENTICATING:
keyguardDone(true);
return;
case SET_HIDDEN:
handleSetHidden(msg.arg1 != 0);
break;
case KEYGUARD_TIMEOUT:
synchronized (KeyguardViewMediator.this) {
doKeyguardLocked();
}
break;
}
}
};
...

------>当case SHOW：时，调用 handleShow方法，如下：

private KeyguardViewManager mKeyguardViewManager;
...
/**
* Handle message sent by {@link #showLocked}.
* @see #SHOW
*/
//显示锁屏界面
private void handleShow() {
synchronized (KeyguardViewMediator.this) {
if (DEBUG) Log.d(TAG, "handleShow");
if (!mSystemReady) return;

mKeyguardViewManager.show();
mShowing = true;
adjustUserActivityLocked();
adjustStatusBarLocked();
try {
ActivityManagerNative.getDefault().closeSystemDialogs("lock");
} catch (RemoteException e) {
}

// Do this at the end to not slow down display of the keyguard.
playSounds(true);

mShowKeyguardWakeLock.release();
}
}
...

----->接着调用KeyguardViewManager的show方法。KeyguardViewManager.show()中，会对KeyguardViewHost(mKeyguardHost)和LockPatternKeyguardView(mKeyguardView)是否为空进行判断：

1）.若KeyguardViewHost为空，则创建KeyguardViewHost，同时设置更新其相关的布局参数。然后将KeyguardViewHost对象添加到WindowManagerImpl中。

2). 若LockPatternKeyguardView为空，创建LockPatternKeyguardView对象，通过调用LockPatternKeyguardViewProperties.createKeyguardView()创建。同时为它设置回调。然后将创建得到的对象添加到KeyguardViewHost。

代码如下：

public class KeyguardViewManager implements KeyguardWindowController {
...
private FrameLayout mKeyguardHost;  //该ViewGroup作为顶层View，作为WindowManager添加至窗口
private KeyguardViewBase mKeyguardView; //具体窗口内容。
//以上两种的关系相当于DecorView和我们Activity内设置的资源文件一样
private final KeyguardViewProperties mKeyguardViewProperties;
...
/**
* Show the keyguard.  Will handle creating and attaching to the view manager
* lazily.
*/
//显示锁屏界面
public synchronized void show() {
if (DEBUG) Log.d(TAG, "show(); mKeyguardView==" + mKeyguardView);

Resources res = mContext.getResources();
boolean enableScreenRotation =
SystemProperties.getBoolean("lockscreen.rot_override",false)
|| res.getBoolean(R.bool.config_enableLockScreenRotation);
if (mKeyguardHost == null) {
if (DEBUG) Log.d(TAG, "keyguard host is null, creating it...");
//创建KeyguardViewHost（FrameLayout）
mKeyguardHost = new KeyguardViewHost(mContext, mCallback);

final int stretch = ViewGroup.LayoutParams.MATCH_PARENT;
int flags = WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN
| WindowManager.LayoutParams.FLAG_SHOW_WALLPAPER
| WindowManager.LayoutParams.FLAG_KEEP_SURFACE_WHILE_ANIMATING
/*| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
| WindowManager.LayoutParams.FLAG_LAYOUT_INSET_DECOR*/ ;
if (!mNeedsInput) {
flags |= WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM;
}
if (ActivityManager.isHighEndGfx(((WindowManager)mContext.getSystemService(
Context.WINDOW_SERVICE)).getDefaultDisplay())) {
flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
}
WindowManager.LayoutParams lp = new WindowManager.LayoutParams(
stretch, stretch, WindowManager.LayoutParams.TYPE_KEYGUARD,
flags, PixelFormat.TRANSLUCENT);
lp.softInputMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE;
lp.windowAnimations = com.android.internal.R.style.Animation_LockScreen;
if (ActivityManager.isHighEndGfx(((WindowManager)mContext.getSystemService(
Context.WINDOW_SERVICE)).getDefaultDisplay())) {
lp.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
lp.privateFlags |=
WindowManager.LayoutParams.PRIVATE_FLAG_FORCE_HARDWARE_ACCELERATED;
}
lp.setTitle("Keyguard");
mWindowLayoutParams = lp;
//添加KeyguardViewHost
mViewManager.addView(mKeyguardHost, lp);
}

if (enableScreenRotation) {
if (DEBUG) Log.d(TAG, "Rotation sensor for lock screen On!");
mWindowLayoutParams.screenOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR;
} else {
if (DEBUG) Log.d(TAG, "Rotation sensor for lock screen Off!");
mWindowLayoutParams.screenOrientation = ActivityInfo.SCREEN_ORIENTATION_NOSENSOR;
}
//刷新布局
mViewManager.updateViewLayout(mKeyguardHost, mWindowLayoutParams);

if (mKeyguardView == null) {
if (DEBUG) Log.d(TAG, "keyguard view is null, creating it...");
/*创建锁屏视图，即创建一个LockPatternKeyguardView对象(FrameLayout)。在创建LockPatternKeyguardView
* 对象的同时，其构造方法中会调用getInitialMode()得到初始化的状态Mode(Lock or unLock)
*/
mKeyguardView = mKeyguardViewProperties.createKeyguardView(mContext, mUpdateMonitor, this);
mKeyguardView.setId(R.id.lock_screen);
//设置回调
mKeyguardView.setCallback(mCallback);

final ViewGroup.LayoutParams lp = new FrameLayout.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT);

//将视图加入根布局mKeyguardHost(FrameLayout)
mKeyguardHost.addView(mKeyguardView, lp);

if (mScreenOn) {
//调用LockPatternKeyguardView的show
mKeyguardView.show();
}
}

// Disable aspects of the system/status/navigation bars that are not appropriate or
// useful for the lockscreen but can be re-shown by dialogs or SHOW_WHEN_LOCKED activities.
// Other disabled bits are handled by the KeyguardViewMediator talking directly to the
// status bar service.
int visFlags =
( View.STATUS_BAR_DISABLE_BACK
| View.STATUS_BAR_DISABLE_HOME
);
mKeyguardHost.setSystemUiVisibility(visFlags);

mViewManager.updateViewLayout(mKeyguardHost, mWindowLayoutParams);
mKeyguardHost.setVisibility(View.VISIBLE);
mKeyguardView.requestFocus();
}
...
}

------>在上面的代码中，当KeyguardViewHost为空时，首先会调用KeyguardViewProperties的实现类LockPatternKeyguardViewProperties的createKeyguardView方法，来构造一个LockPatternKeyguardView对象，如下：

public class LockPatternKeyguardViewProperties implements KeyguardViewProperties {
...
//创建一个LockPatternKeyguardView对象
public KeyguardViewBase createKeyguardView(Context context,
KeyguardUpdateMonitor updateMonitor,
KeyguardWindowController controller) {
return new LockPatternKeyguardView(context, updateMonitor,
mLockPatternUtils, controller);
}
...
}

------->而在LockPatternKeyguardView的构造函数中，有如下调用(以下的流程代码实现均在LockPatternKeyguardView中处理)：

/**
* @param context Used to inflate, and create views.
* @param updateMonitor Knows the state of the world, and passed along to each
*   screen so they can use the knowledge, and also register for callbacks
*   on dynamic information.
* @param lockPatternUtils Used to look up state of lock pattern.
*/
public LockPatternKeyguardView(
Context context,
KeyguardUpdateMonitor updateMonitor,
LockPatternUtils lockPatternUtils,
KeyguardWindowController controller) {
...
updateScreen(getInitialMode(), false);
...

}

----->getInitialMode()得到当前锁屏模式（lock or unlock），代码如下：

...
/**
* Given the current state of things, what should be the initial mode of
* the lock screen (lock or unlock).
*/
//得到初始化的状态Mode (lock or unlock).
private Mode getInitialMode() {
final IccCard.State simState = mUpdateMonitor.getSimState();
if (stuckOnLockScreenBecauseSimMissing() ||
(simState == IccCard.State.PUK_REQUIRED &&
!mLockPatternUtils.isPukUnlockScreenEnable())) {
return Mode.LockScreen;
} else {
if (!isSecure() || mShowLockBeforeUnlock) {
return Mode.LockScreen;
} else {
return Mode.UnlockScreen;
}
}
}
...

----->再回到updateScreen(getInitialMode(), false)，该函数的实现如下：

...
//根据参数（Lock/unLock），判断显示为LockScreen或者UnlockScreen界面
private void updateScreen(Mode mode, boolean force) {

if (DEBUG_CONFIGURATION) Log.v(TAG, "**** UPDATE SCREEN: mode=" + mode
+ " last mode=" + mMode + ", force = " + force, new RuntimeException());

mMode = mode;

// Re-create the lock screen if necessary
if (mode == Mode.LockScreen || mShowLockBeforeUnlock) {
if (force || mLockScreen == null) {
//重构LockScreen
recreateLockScreen();
}
}

// Re-create the unlock screen if necessary. This is primarily required to properly handle
// SIM state changes. This typically happens when this method is called by reset()
if (mode == Mode.UnlockScreen) {
//获取UnlockScreen的具体解锁项，如密码锁(Password)或pin锁；枚举类UnlockMode定义了几种不同的Unlock解锁；
final UnlockMode unlockMode = getUnlockMode();
if (force || mUnlockScreen == null || unlockMode != mUnlockScreenMode) {
//重构unLock解锁
recreateUnlockScreen(unlockMode);
}
}

// visibleScreen should never be null
final View goneScreen = (mode == Mode.LockScreen) ? mUnlockScreen : mLockScreen;
final View visibleScreen = (mode == Mode.LockScreen) ? mLockScreen : mUnlockScreen;

// do this before changing visibility so focus isn't requested before the input
// flag is set
mWindowController.setNeedsInput(((KeyguardScreen)visibleScreen).needsInput());

if (DEBUG_CONFIGURATION) {
Log.v(TAG, "Gone=" + goneScreen);
Log.v(TAG, "Visible=" + visibleScreen);
}

if (mScreenOn) {
if (goneScreen != null && goneScreen.getVisibility() == View.VISIBLE) {
((KeyguardScreen) goneScreen).onPause(); //隐藏被切换掉的锁(Lock or unLock)
}
if (visibleScreen.getVisibility() != View.VISIBLE) {
((KeyguardScreen) visibleScreen).onResume();//显示切换得到的锁(Lock or unLock)
}
}

if (goneScreen != null) {
goneScreen.setVisibility(View.GONE);
}
visibleScreen.setVisibility(View.VISIBLE);
requestLayout();

if (!visibleScreen.requestFocus()) {
throw new IllegalStateException("keyguard screen must be able to take "
+ "focus when shown " + visibleScreen.getClass().getCanonicalName());
}
}
...

------>在updateScreen(getInitialMode(), false)中，对传进来的参数Mode进行对等判断：

1). 若为LockScreen模式锁屏，则如下：

// Re-create the lock screen if necessary
if (mode == Mode.LockScreen || mShowLockBeforeUnlock) {
if (force || mLockScreen == null) {
//重构LockScreen
recreateLockScreen();
}
}

----->然后调用到LockPatternKeyguardView.recreateLockScreen()，在该函数中，首先会对LockScreen进行判断，若之前已存在该对象，则进行移除。然后接着再重新调用createLockScreen()构建LockScreen对象。然后将该对象添加到LockPatternKeyguardView中。createLockScreen()的代码如下：

...
//创建lockScreen
View createLockScreen() {
View lockView = new LockScreen(
mContext,
mConfiguration,
mLockPatternUtils,
mUpdateMonitor,
mKeyguardScreenCallback);
initializeTransportControlView(lockView);
return lockView;
}
...

2).若为UnlockScreen模式锁屏，则如下：

// Re-create the unlock screen if necessary. This is primarily required to properly handle
// SIM state changes. This typically happens when this method is called by reset()
if (mode == Mode.UnlockScreen) {
//获取UnlockScreen的具体解锁项，如密码锁(Password)或pin锁；枚举类UnlockMode定义了几种不同的Unlock解锁；
final UnlockMode unlockMode = getUnlockMode();
if (force || mUnlockScreen == null || unlockMode != mUnlockScreenMode) {
//重构unLock解锁
recreateUnlockScreen(unlockMode);
}
}

----->然后调用到LockPatternKeyguardView.recreateUnlockScreen(unlockMode)，在该函数中，进行的处理和recreateLockScreen函数中的处理原则基本上一致。则调用createUnlockScreen(unlockMode)时，会根据unlockMode的不同创建相应的UnlockScreen具体解锁项。

recreateUnlockScreen如下代码：

...
//重新构建UnlockScreen
private void recreateUnlockScreen(UnlockMode unlockMode) {
if (mUnlockScreen != null) {
((KeyguardScreen) mUnlockScreen).onPause();
((KeyguardScreen) mUnlockScreen).cleanUp();
//mUnlockScreen不为空，则移除UnlockScreen
removeView(mUnlockScreen);
}

mUnlockScreen = createUnlockScreenFor(unlockMode);
mUnlockScreen.setVisibility(View.INVISIBLE);
//将UnlockScreen添进LockPatternKeyguardView
addView(mUnlockScreen);
}
...

----->接着调用createUnlockScreenFor方法，在该方法中会根据传进来的参数UnlockMode(定义UnlockScreen可选项的枚举类)判断，来决定创建启用对应的UnlockScreen，代码实现如下：

...
//根据不同的Unlock Mode ， 创建不同的UnlockScreen
View createUnlockScreenFor(UnlockMode unlockMode) {
View unlockView = null;

if (DEBUG) Log.d(TAG,
"createUnlockScreenFor(" + unlockMode + "): mEnableFallback=" + mEnableFallback);

if (unlockMode == UnlockMode.Pattern) {
//启动图案解锁（手机设置中可见切换）
PatternUnlockScreen view = new PatternUnlockScreen(
mContext,
mConfiguration,
mLockPatternUtils,
mUpdateMonitor,
mKeyguardScreenCallback,
mUpdateMonitor.getFailedAttempts());
view.setEnableFallback(mEnableFallback);
unlockView = view;
} else if (unlockMode == UnlockMode.SimPuk) {
unlockView = new SimPukUnlockScreen(
mContext,
mConfiguration,
mUpdateMonitor,
mKeyguardScreenCallback,
mLockPatternUtils);
} else if (unlockMode == UnlockMode.SimPin) {
//启动PIN解锁（手机设置中可见切换）
unlockView = new SimUnlockScreen(
mContext,
mConfiguration,
mUpdateMonitor,
mKeyguardScreenCallback,
mLockPatternUtils);
} else if (unlockMode == UnlockMode.Account) {
try {
unlockView = new AccountUnlockScreen(
mContext,
mConfiguration,
mUpdateMonitor,
mKeyguardScreenCallback,
mLockPatternUtils);
} catch (IllegalStateException e) {
Log.i(TAG, "Couldn't instantiate AccountUnlockScreen"
+ " (IAccountsService isn't available)");
// TODO: Need a more general way to provide a
// platform-specific fallback UI here.
// For now, if we can't display the account login
// unlock UI, just bring back the regular "Pattern" unlock mode.

// (We do this by simply returning a regular UnlockScreen
// here.  This means that the user will still see the
// regular pattern unlock UI, regardless of the value of
// mUnlockScreenMode or whether or not we're in the
// "permanently locked" state.)
return createUnlockScreenFor(UnlockMode.Pattern);
}
} else if (unlockMode == UnlockMode.Password) {
//启动密码解锁（手机设置中可见切换）
unlockView = new PasswordUnlockScreen(
mContext,
mConfiguration,
mLockPatternUtils,
mUpdateMonitor,
mKeyguardScreenCallback);
} else {
throw new IllegalArgumentException("unknown unlock mode " + unlockMode);
}
initializeTransportControlView(unlockView);
initializeFaceLockAreaView(unlockView); // Only shows view if FaceLock is enabled

mUnlockScreenMode = unlockMode;
return unlockView;
}
...

在此，LockScreen或者UnlockScreen就创建出来了，当然，只是创建了相应对象，还得再显示。

------>再次回到KeyguardViewManager类的show方法，在执行完该方法中的的mKeyguardView = mKeyguardViewProperties.createKeyguardView(mContext,
mUpdateMonitor, this)代码流程后，接着执行mKeyguardView.show()，即调用KeyguardViewBase的实现类LockPatternKeyguardView的show方法，如下：

//该类作为LockScreen和UnLockScreen界面的载体，控制显示哪个界面
public class LockPatternKeyguardView extends KeyguardViewBase implements Handler.Callback,
KeyguardUpdateMonitor.InfoCallback {
...
@Override
public void show() {
/*判断锁屏模式(当然，调用该方法之前已经创建LockPatternKeyguardView对象，
* 即已调用getInitialMode()获得了Mode)，根据结果显示锁屏。
*/
if (mMode == Mode.LockScreen) {
//调用onResume显示锁屏
((KeyguardScreen) mLockScreen).onResume();
} else {
((KeyguardScreen) mUnlockScreen).onResume();
}

if (mLockPatternUtils.usingBiometricWeak() &&
mLockPatternUtils.isBiometricWeakInstalled() && !mHasOverlay) {
// Note that show() gets called before the screen turns off to set it up for next time
// it is turned on.  We don't want to set a timeout on the FaceLock area here because it
// may be gone by the time the screen is turned on again.  We set the timout when the
// screen turns on instead.
showFaceLockArea(); //显示人脸解锁区域
} else {
hideFaceLockArea(); //隐藏人脸解锁区域
}
}
...
}

这样，LockScreen或者UnlockScreen就显示出来了，我们再来看看LockScreen的onResume()方法的实现，代码如下：

//手机默认的解锁实现类
class LockScreen extends LinearLayout implements KeyguardScreen {
...
//处理LockScreen的显示
public void onResume() {
mStatusViewManager.onResume();
postDelayed(mOnResumePing, ON_RESUME_PING_DELAY);
}
...
}

对于LockScreen或者UnlockScreen的界面布局和View等可视化UI界面时如何画出来的，具体可参考LockScreen类的实现，UnlockScreen可参考的类：PatternUnlockScreen、SimPukUnlockScreen、SimUnlockScreen、AccountUnlockScreen、PasswordUnlockScreen。有兴趣的读者可自行去研究。

小结：

这篇文章只是讲解手机开机启动时，绘制锁屏的流程，至于通过power键点亮，点暗锁屏，解锁，锁屏，LockScreen或者UnlockScreen的UI界面可视化的实现等等的分析，有时间再去深究。

但，万变不离其宗，锁屏的核心类在于KeyguardViewMediator，该类提供了一些接口，由PhoneWindowManager去访问控制Keyguard，而它的初始化是在PhoneWindowManager的init()函数中创建的。也就是在我们上面分析的代码中，在执行mPolicy.systemReady()时(由PhoneWindowManage调用r)，已经创建了KeyguardViewMediator。所以，分析好该类是很重要的。

OK，个人对锁屏开机绘制流程的粗略分析就到这里了，春节即将来临，在此祝愿所有身处挨踢行业的同志们，回家过个好年！！