概述
window
-
window是一個抽象類，具體實現是PhoneWindow -
window也是一個抽象的概念，每個 window 內對應這一個DecorView和一個ViewRootImpl，window和DecorView通過ViewRootImpl聯系。
WindowManager
WindowManager 是 外界訪問 Window 的入口
WindowManagerService
window 的具體實現位于WindowManagerService中，WindowManager和WindowManagerService的交互是一個 IPC 的過程，
源碼分析
window 的添加、刪除、更新 view 均是通過WindowManager來完成的，而WindowManager繼承了 ViewManager的接口
/** Interface to let you add and remove child views to an Activity. To get an instance
* of this class, call {@link android.content.Context#getSystemService(java.lang.String) Context.getSystemService()}.
*/
public interface ViewManager
{
/**
* Assign the passed LayoutParams to the passed View and add the view to the window.
* <p>Throws {@link android.view.WindowManager.BadTokenException} for certain programming
* errors, such as adding a second view to a window without removing the first view.
* <p>Throws {@link android.view.WindowManager.InvalidDisplayException} if the window is on a
* secondary {@link Display} and the specified display can't be found
* (see {@link android.app.Presentation}).
* @param view The view to be added to this window.
* @param params The LayoutParams to assign to view.
*/
public void addView(View view, ViewGroup.LayoutParams params);
public void updateViewLayout(View view, ViewGroup.LayoutParams params);
public void removeView(View view);
}
對應的三個方法，繼續看WindowManager對應的具體實現類，WindowManagerImple
@Override
public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
applyDefaultToken(params);
mGlobal.addView(view, params, mDisplay, mParentWindow);
}
@Override
public void removeView(View view) {
mGlobal.removeView(view, false);
}
@Override
public void updateViewLayout(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
applyDefaultToken(params);
mGlobal.updateViewLayout(view, params);
}
可以看到，具體的方法均交給WindowManagerGlobal來處理，而WindowManagerGlobal則以工程模式提供了自己的實例
private final WindowManagerGlobal mGlobal = WindowManagerGlobal.getInstance();
看看``中比較重要的幾個成員變量
private final ArrayList<View> mViews = new ArrayList<View>();//所有 window 對應的 DecorView
private final ArrayList<ViewRootImpl> mRoots = new ArrayList<ViewRootImpl>();////所有 window 對應的 ViewRootImpl
private final ArrayList<WindowManager.LayoutParams> mParams =
new ArrayList<WindowManager.LayoutParams>(); //所有 window 對應的 WindowManager.LayoutParams
private final ArraySet<View> mDyingViews = new ArraySet<View>();//所有 window 對應需要刪除的 view
添加過程
具體分析WindowManagerGlobal的addview
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow) {
//首先檢查了參數，并拋出對應的異常
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
if (display == null) {
throw new IllegalArgumentException("display must not be null");
}
if (!(params instanceof WindowManager.LayoutParams)) {
throw new IllegalArgumentException("Params must be WindowManager.LayoutParams");
}
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
if (parentWindow != null) {
parentWindow.adjustLayoutParamsForSubWindow(wparams);
} else {
// If there's no parent, then hardware acceleration for this view is
// set from the application's hardware acceleration setting.
final Context context = view.getContext();
if (context != null
&& (context.getApplicationInfo().flags
& ApplicationInfo.FLAG_HARDWARE_ACCELERATED) != 0) {
wparams.flags |= WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
}
}
ViewRootImpl root;
View panelParentView = null;
synchronized (mLock) {
// Start watching for system property changes.
if (mSystemPropertyUpdater == null) {
mSystemPropertyUpdater = new Runnable() {
@Override public void run() {
synchronized (mLock) {
for (int i = mRoots.size() - 1; i >= 0; --i) {
mRoots.get(i).loadSystemProperties();
}
}
}
};
SystemProperties.addChangeCallback(mSystemPropertyUpdater);
}
//通過findViewLocked找到 view 對應的 index
int index = findViewLocked(view, false);
if (index >= 0) {
//如果找到了，說明這個 view 已經被添加進來了
if (mDyingViews.contains(view)) {
//這個 view 是需要刪除的話，那么不用管直接用doDie 刪除
// Don't wait for MSG_DIE to make it's way through root's queue.
mRoots.get(index).doDie();
} else {
//說明這個 view 已經被添加進來了,拋出異常
throw new IllegalStateException("View " + view
+ " has already been added to the window manager.");
}
// The previous removeView() had not completed executing. Now it has.
}
// If this is a panel window, then find the window it is being
// attached to for future reference.
if (wparams.type >= WindowManager.LayoutParams.FIRST_SUB_WINDOW &&
wparams.type <= WindowManager.LayoutParams.LAST_SUB_WINDOW) {
final int count = mViews.size();
for (int i = 0; i < count; i++) {
//找到對應的 window
if (mRoots.get(i).mWindow.asBinder() == wparams.token) {
panelParentView = mViews.get(i);
}
}
}
root = new ViewRootImpl(view.getContext(), display);
view.setLayoutParams(wparams);
//將得DecorView viewimpl params 都加入到 list 中
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
}
// do this last because it fires off messages to start doing things
try {
//這個重要，通過 viewrootImpl 的 setview 方法來刷新 view
root.setView(view, wparams, panelParentView);
} catch (RuntimeException e) {
// BadTokenException or InvalidDisplayException, clean up.
synchronized (mLock) {
final int index = findViewLocked(view, false);
if (index >= 0) {
removeViewLocked(index, true);
}
}
throw e;
}
}
setview 的方法比較長，看其中比較重要的幾個方法
requestLayout();
@Override
public void requestLayout() {
if (!mHandlingLayoutInLayoutRequest) {
checkThread();
mLayoutRequested = true;
scheduleTraversals();
}
}
scheduleTraversals 是 view 開始繪制的入口
繼續往下看 window 的添加過程
mOrigWindowType = mWindowAttributes.type;
mAttachInfo.mRecomputeGlobalAttributes = true;
collectViewAttributes();
res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
getHostVisibility(), mDisplay.getDisplayId(),
mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
mAttachInfo.mOutsets, mInputChannel);
IWindowSession是一個 binder 對象。最終會調用到windowManagerService中的方法
刪除過程
具體分析WindowManagerGlobal的removeview
public void removeView(View view, boolean immediate) {
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
synchronized (mLock) {
//找到對應的 index ，再removeViewLocked
int index = findViewLocked(view, true);
View curView = mRoots.get(index).getView();
removeViewLocked(index, immediate);
if (curView == view) {
return;
}
throw new IllegalStateException("Calling with view " + view
+ " but the ViewAncestor is attached to " + curView);
}
}
private void removeViewLocked(int index, boolean immediate) {
ViewRootImpl root = mRoots.get(index);
View view = root.getView();
if (view != null) {
InputMethodManager imm = InputMethodManager.getInstance();
if (imm != null) {
imm.windowDismissed(mViews.get(index).getWindowToken());
}
}
// ViewRootImpl 的 die 方法
boolean deferred = root.die(immediate);
if (view != null) {
view.assignParent(null);
if (deferred) {
mDyingViews.add(view);
}
}
}
//die 方法比較簡單，就是發送了一個 message，最后在處理 message 的時候調用了doDie
boolean die(boolean immediate) {
// Make sure we do execute immediately if we are in the middle of a traversal or the damage
// done by dispatchDetachedFromWindow will cause havoc on return.
if (immediate && !mIsInTraversal) {
doDie();
return false;
}
if (!mIsDrawing) {
destroyHardwareRenderer();
} else {
Log.e(TAG, "Attempting to destroy the window while drawing!\n" +
" window=" + this + ", title=" + mWindowAttributes.getTitle());
}
mHandler.sendEmptyMessage(MSG_DIE);
return true;
}
void doDie() {
checkThread();
if (LOCAL_LOGV) Log.v(TAG, "DIE in " + this + " of " + mSurface);
synchronized (this) {
if (mRemoved) {
return;
}
mRemoved = true;
if (mAdded) {
//這里做了一些資源的回抽，停動畫等
dispatchDetachedFromWindow();
}
if (mAdded && !mFirst) {
destroyHardwareRenderer();
if (mView != null) {
int viewVisibility = mView.getVisibility();
boolean viewVisibilityChanged = mViewVisibility != viewVisibility;
if (mWindowAttributesChanged || viewVisibilityChanged) {
// If layout params have been changed, first give them
// to the window manager to make sure it has the correct
// animation info.
try {
if ((relayoutWindow(mWindowAttributes, viewVisibility, false)
& WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) {
mWindowSession.finishDrawing(mWindow);
}
} catch (RemoteException e) {
}
}
mSurface.release();
}
}
mAdded = false;
}
//在其中清理 那些成員 list 變量
WindowManagerGlobal.getInstance().doRemoveView(this);
}
更新過程
public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
if (!(params instanceof WindowManager.LayoutParams)) {
throw new IllegalArgumentException("Params must be WindowManager.LayoutParams");
}
final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams)params;
view.setLayoutParams(wparams);
synchronized (mLock) {
//刪除舊的 param 更新成新的 param
int index = findViewLocked(view, true);
ViewRootImpl root = mRoots.get(index);
mParams.remove(index);
mParams.add(index, wparams);
//通過 viewrootImpl 來刷新 view
root.setLayoutParams(wparams, false);
}
}
拓展閱讀 window、Activity、DecorView、ViewRoot關系
參考
http://gold.xitu.io/entry/571338c7c4c9710054cea455
http://www.lxweimin.com/p/687010ccad66
