page7
在这篇文章里, 我们分析一下W类的构造过程. W类是定义在ViewRootImpl类中的一个内部类, W类的定义如下:
static class W extends IWindow.Stub
由此可见, W本质上是一个Binder本地对象, 其实这是会传给WindowManagerService的, WindowManagerService就是通过W来通知Activity对象执行一些操作.
W的构造函数如下:
W(ViewRootImpl viewAncestor) {
mViewAncestor = new WeakReference<ViewRootImpl>(viewAncestor);
mWindowSession = viewAncestor.mWindowSession;
}
由此可见, W拿着ViewRootImpl和WindowSession.
page8
我们分析一下ViewRootImpl的setView函数的实现:
1 public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
2 synchronized (this) {
3 if (mView == null) {
4 mView = view;
5 mViewLayoutDirectionInitial = mView.getRawLayoutDirection();
6 mFallbackEventHandler.setView(view);
7 mWindowAttributes.copyFrom(attrs);
8 attrs = mWindowAttributes;
9 // Keep track of the actual window flags supplied by the client.
10 mClientWindowLayoutFlags = attrs.flags;
11
12 setAccessibilityFocus(null, null);
13
14 if (view instanceof RootViewSurfaceTaker) {
15 mSurfaceHolderCallback =
16 ((RootViewSurfaceTaker)view).willYouTakeTheSurface();
17 if (mSurfaceHolderCallback != null) {
18 mSurfaceHolder = new TakenSurfaceHolder();
19 mSurfaceHolder.setFormat(PixelFormat.UNKNOWN);
20 }
21 }
22
23 CompatibilityInfo compatibilityInfo = mCompatibilityInfo.get();
24 mTranslator = compatibilityInfo.getTranslator();
25
26 // If the application owns the surface, don't enable hardware acceleration
27 if (mSurfaceHolder == null) {
28 enableHardwareAcceleration(mView.getContext(), attrs);
29 }
30
31 boolean restore = false;
32 if (mTranslator != null) {
33 mSurface.setCompatibilityTranslator(mTranslator);
34 restore = true;
35 attrs.backup();
36 mTranslator.translateWindowLayout(attrs);
37 }
38 if (DEBUG_LAYOUT) Log.d(TAG, "WindowLayout in setView:" + attrs);
39
40 if (!compatibilityInfo.supportsScreen()) {
41 attrs.flags |= WindowManager.LayoutParams.FLAG_COMPATIBLE_WINDOW;
42 mLastInCompatMode = true;
43 }
44
45 mSoftInputMode = attrs.softInputMode;
46 mWindowAttributesChanged = true;
47 mWindowAttributesChangesFlag = WindowManager.LayoutParams.EVERYTHING_CHANGED;
48 mAttachInfo.mRootView = view;
49 mAttachInfo.mScalingRequired = mTranslator != null;
50 mAttachInfo.mApplicationScale =
51 mTranslator == null ? 1.0f : mTranslator.applicationScale;
52 if (panelParentView != null) {
53 mAttachInfo.mPanelParentWindowToken
54 = panelParentView.getApplicationWindowToken();
55 }
56 mAdded = true;
57 int res; /* = WindowManagerImpl.ADD_OKAY; */
58
59 // Schedule the first layout -before- adding to the window
60 // manager, to make sure we do the relayout before receiving
61 // any other events from the system.
62 requestLayout();
63 if ((mWindowAttributes.inputFeatures
64 & WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHANNEL) == 0) {
65 mInputChannel = new InputChannel();
66 }
67 try {
68 mOrigWindowType = mWindowAttributes.type;
69 mAttachInfo.mRecomputeGlobalAttributes = true;
70 collectViewAttributes();
71 res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
72 getHostVisibility(), mDisplay.getDisplayId(),
73 mAttachInfo.mContentInsets, mInputChannel);
74 } catch (RemoteException e) {
75 mAdded = false;
76 mView = null;
77 mAttachInfo.mRootView = null;
78 mInputChannel = null;
79 mFallbackEventHandler.setView(null);
80 unscheduleTraversals();
81 setAccessibilityFocus(null, null);
82 throw new RuntimeException("Adding window failed", e);
83 } finally {
84 if (restore) {
85 attrs.restore();
86 }
87 }
88
89 if (mTranslator != null) {
90 mTranslator.translateRectInScreenToAppWindow(mAttachInfo.mContentInsets);
91 }
92 mPendingContentInsets.set(mAttachInfo.mContentInsets);
93 mPendingVisibleInsets.set(0, 0, 0, 0);
94 if (DEBUG_LAYOUT) Log.v(TAG, "Added window " + mWindow);
95 if (res < WindowManagerGlobal.ADD_OKAY) {
96 mAttachInfo.mRootView = null;
97 mAdded = false;
98 mFallbackEventHandler.setView(null);
99 unscheduleTraversals();
100 setAccessibilityFocus(null, null);
101 switch (res) {
102 case WindowManagerGlobal.ADD_BAD_APP_TOKEN:
103 case WindowManagerGlobal.ADD_BAD_SUBWINDOW_TOKEN:
104 throw new WindowManager.BadTokenException(
105 "Unable to add window -- token " + attrs.token
106 + " is not valid; is your activity running?");
107 case WindowManagerGlobal.ADD_NOT_APP_TOKEN:
108 throw new WindowManager.BadTokenException(
109 "Unable to add window -- token " + attrs.token
110 + " is not for an application");
111 case WindowManagerGlobal.ADD_APP_EXITING:
112 throw new WindowManager.BadTokenException(
113 "Unable to add window -- app for token " + attrs.token
114 + " is exiting");
115 case WindowManagerGlobal.ADD_DUPLICATE_ADD:
116 throw new WindowManager.BadTokenException(
117 "Unable to add window -- window " + mWindow
118 + " has already been added");
119 case WindowManagerGlobal.ADD_STARTING_NOT_NEEDED:
120 // Silently ignore -- we would have just removed it
121 // right away, anyway.
122 return;
123 case WindowManagerGlobal.ADD_MULTIPLE_SINGLETON:
124 throw new WindowManager.BadTokenException(
125 "Unable to add window " + mWindow +
126 " -- another window of this type already exists");
127 case WindowManagerGlobal.ADD_PERMISSION_DENIED:
128 throw new WindowManager.BadTokenException(
129 "Unable to add window " + mWindow +
130 " -- permission denied for this window type");
131 case WindowManagerGlobal.ADD_INVALID_DISPLAY:
132 throw new WindowManager.InvalidDisplayException(
133 "Unable to add window " + mWindow +
134 " -- the specified display can not be found");
135 }
136 throw new RuntimeException(
137 "Unable to add window -- unknown error code " + res);
138 }
139
140 if (view instanceof RootViewSurfaceTaker) {
141 mInputQueueCallback =
142 ((RootViewSurfaceTaker)view).willYouTakeTheInputQueue();
143 }
144 if (mInputChannel != null) {
145 if (mInputQueueCallback != null) {
146 mInputQueue = new InputQueue(mInputChannel);
147 mInputQueueCallback.onInputQueueCreated(mInputQueue);
148 } else {
149 mInputEventReceiver = new WindowInputEventReceiver(mInputChannel,
150 Looper.myLooper());
151 }
152 }
153
154 view.assignParent(this);
155 mAddedTouchMode = (res & WindowManagerGlobal.ADD_FLAG_IN_TOUCH_MODE) != 0;
156 mAppVisible = (res & WindowManagerGlobal.ADD_FLAG_APP_VISIBLE) != 0;
157
158 if (mAccessibilityManager.isEnabled()) {
159 mAccessibilityInteractionConnectionManager.ensureConnection();
160 }
161
162 if (view.getImportantForAccessibility() == View.IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
163 view.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);
164 }
165 }
166 }
167 }
168
第2行(ViewRootImpl->setView)会加锁
第3行(ViewRootImpl->setView)会保证一个ViewRootImpl只对应一个View
第4行(ViewRootImpl->setView)将成员变量mView设置成DecorView
第62行(ViewRootImpl->setView)会调用requestLayout()函数来进行一次layout, 而这是在加入到WindowManagerService管理之前进行的, 关于这部分的分析可以参考View的刷新部分的分析.
第71-73行(ViewRootImpl->setView)会调用WindowSession的addToDisplay函数将mWindow传给WindowManagerService, 关于这部分的分析可以参考Activity和WindowManagerService连接系列的文章.
page9
我们来看一下PhoneWidnow的getDecorView函数的实现:
public final View getDecorView() {
if (mDecor == null) {
installDecor();
}
return mDecor;
}
getDecorView函数如果发现mDecor还没有初始化过, 就会调用installDecor函数来构造一个DecorView
Activity的ViewRoot的创建过程(三)
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转载自zzu-007.iteye.com/blog/2398795
周排行