AndroidによるWindowオブジェクトの管理メカニズムの分析

転載は出典を明記してください.http://blog.csdn.net/crazy1235/article/details/72625679
Windowオブジェクト管理に関するカテゴリ:

View Manager

WindowManager

WindowManagerImpl

WindowManagerGlobal

View Part

View RootImpl

ActvityThread

WindowManagerService

Windowは抽象的なタイプで、具体的な実現類はPhone Windowです.
WindowはViewで積載されています.View RootImplにも対応しています.
WindowにアクセスするにはWindowManagerを通じて実現しなければなりません.
Windowの具体的な操作方法はWindowManager Impl類の中で実現して、方法はView Managerインターフェイスの中で定義します!

public interface ViewManager
{    
    public void addView(View view, ViewGroup.LayoutParams params);
    public void updateViewLayout(View view, ViewGroup.LayoutParams params);
    public void removeView(View view);
}

View Managerインターフェイスは三つの関数を定義しています.それぞれwindowの追加、更新、削除に対応しています.

addView

 @Override
    public void addView(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
        applyDefaultToken(params);
        mGlobal.addView(view, params, mContext.getDisplay(), mParentWindow);

実はWindowManagerImplも具体的な操作をしていません.WindowManagerGlobalに任せました.
WindowManagerImplクラスで初期化されました.

private final WindowManagerGlobal mGlobal = WindowManagerGlobal.getInstance();

WindowManager Global.java

private WindowManagerGlobal() {
    }

    public static WindowManagerGlobal getInstance() {
        synchronized (WindowManagerGlobal.class) {
            if (sDefaultWindowManager == null) {
                sDefaultWindowManager = new WindowManagerGlobal();
            }
            return sDefaultWindowManager;
        }
    }

これは一例のパターンです.

private final ArrayList mViews = new ArrayList();
private final ArrayList mRoots = new ArrayList();
private final ArrayList mParams =
            new ArrayList();
private final ArraySet mDyingViews = new ArraySet();

WindowManager Globalには4つの重要な集合があります.

mViewセットには、すべてのwindow対応のViewオブジェクトが格納されています.

mRoots集合は、すべてのwindowに対応するView RootImplオブジェクト

を記憶している.

mParamsのセットは、すべてのwindowに対応するレイアウトパラメータ

を記憶している.

mDyingViewのセットには、削除されているすべてのwindowオブジェクト

が格納されている.

public void addView(View view, ViewGroup.LayoutParams params,
            Display display, Window parentWindow) {
        // 1.     ！
        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 {
            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; //   ViewRootImpl  
        View panelParentView = null; //   View  

        synchronized (mLock) {
            // ...
            //   view   index
            int index = findViewLocked(view, false);
            if (index >= 0) {
                if (mDyingViews.contains(view)) {//              view，   ViewRootImpl.doDie()  
                    mRoots.get(index).doDie();
                } else {
                    throw new IllegalStateException("View " + view
                            + " has already been added to the window manager.");
                }
           }

            // ... 

            //   ViewRootImpl  
            root = new ViewRootImpl(view.getContext(), display);
            //       
            view.setLayoutParams(wparams);

            //   view    
            mViews.add(view);
            //   ViewRootImpl    
            mRoots.add(root);
            //   wparams      
            mParams.add(wparams);
        }

        try {
            //  view   ViewRootImpl ！
            root.setView(view, wparams, panelParentView);
        } catch (RuntimeException e) {
            //        view
            synchronized (mLock) {
                final int index = findViewLocked(view, false);
                if (index >= 0) {
                    removeViewLocked(index, true);
                }
            }
            throw e;
        }
    }

関数は最後にView RootImpl.setView()を通じてwindowの添加過程を完成します.
set View()の内部でrequest Layout()を呼び出し、描画プロセスを開始しました.
Viewの描画プロセスはView RootImplによって完成されます.
request Layout()描画プロセスが完了したら、WindowSessionを通じてWindowの追加プロセスが完了します.

public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
            // ...

            try {
                    mOrigWindowType = mWindowAttributes.type;
                    mAttachInfo.mRecomputeGlobalAttributes = true;
                    collectViewAttributes();
                    res = mWindowSession.addToDisplay(mWindow, mSeq, mWindowAttributes,
                            getHostVisibility(), mDisplay.getDisplayId(),
                            mAttachInfo.mContentInsets, mAttachInfo.mStableInsets,
                            mAttachInfo.mOutsets, mInputChannel);
                } catch (RemoteException e) {
                    mAdded = false;
                    mView = null;
                    mAttachInfo.mRootView = null;
                    mInputChannel = null;
                    mFallbackEventHandler.setView(null);
                    unscheduleTraversals();
                    setAccessibilityFocus(null, null);
                    throw new RuntimeException("Adding window failed", e);
                } finally {
                    if (restore) {
                        attrs.restore();
                    }
                }

            // ...
}

mWindowSessionは、Binderオブジェクトです.
本当の実現者はSessionです.

@Override
    public int addToDisplay(IWindow window, int seq, WindowManager.LayoutParams attrs,
            int viewVisibility, int displayId, Rect outContentInsets, Rect outStableInsets,
            Rect outOutsets, InputChannel outInputChannel) {
        return mService.addWindow(this, window, seq, attrs, viewVisibility, displayId,
                outContentInsets, outStableInsets, outOutsets, outInputChannel);
    }

ここでWindow Manager Serviceを通じてwindowの追加を実現します.そうすると、windowの追加事務はWMSに任せて処理します.
udateView Layout
WindowMangerImpl.java

@Override
    public void updateViewLayout(@NonNull View view, @NonNull ViewGroup.LayoutParams params) {
        applyDefaultToken(params);
        mGlobal.updateViewLayout(view, params);
    }

public void updateViewLayout(View view, ViewGroup.LayoutParams params) {
        // ...
        final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams)params;
        //         
        view.setLayoutParams(wparams); 

        synchronized (mLock) {
            int index = findViewLocked(view, true);
            ViewRootImpl root = mRoots.get(index);
            mParams.remove(index);
            mParams.add(index, wparams); //   mParams      
            root.setLayoutParams(wparams, false); //   ViewRootImpl    , false        view
        }
    }

View RooImpl.java

void setLayoutParams(WindowManager.LayoutParams attrs, boolean newView) {
        synchronized (this) {
            // ...

            if (newView) {
                mSoftInputMode = attrs.softInputMode;
                requestLayout();
            }

            //...

            mWindowAttributesChanged = true;
            scheduleTraversals();
        }
    }

この関数では、scheduleTraversals()を呼び出して測定、レイアウト、描画プロセスを行います.
removeView
View Managerインターフェースには削除機能が一つしかありません.

public void removeView(View view);

WindowManagerインターフェースにviewを削除する方法が追加されました.

public void removeViewImmediate(View view); //     

この2つの方法は、同期削除を表し、非同期削除を表します.
どちらもWindows ManagerGlobalのremoveView()関数を呼び出します.
WindowManagerImpl.java

@Override
    public void removeView(View view) {
        mGlobal.removeView(view, false);
    }

@Override
    public void removeViewImmediate(View view) {
        mGlobal.removeView(view, true);
    }

WindowManager Global.java

public void removeView(View view, boolean immediate) {
        if (view == null) {
            throw new IllegalArgumentException("view must not be null");
        }

        synchronized (mLock) {
            //       view   
            int index = findViewLocked(view, true);
            //  mRoots       view  
            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);
        }
    }

removeView()二つ目のパラメータはすぐに削除するかどうかを表します.

private void removeViewLocked(int index, boolean immediate) {
        //   view   ViewRootImpl  
        ViewRootImpl root = mRoots.get(index);
        View view = root.getView();

        // ...
        //   View  die()  
        boolean deferred = root.die(immediate);
        if (view != null) {
            view.assignParent(null);
            if (deferred) { //             
                mDyingViews.add(view);
            }
        }
    }

View Root Impl.java

boolean die(boolean immediate) {
        //      ，    doDie()           ！    false
        if (immediate && !mIsInTraversal) {
            doDie();
            return false;
        }

        // ...
        //      ，           ，      true
        mHandler.sendEmptyMessage(MSG_DIE);
        return true;
    }

実は非同期削除時に、handler処理時も呼び出したdoDie()関数で削除を完了します.

case MSG_DIE:
   doDie();
   break;

View Root Impl.java

void doDie() {
        checkThread(); //     ,             ！

        synchronized (this) {
            if (mRemoved) { // mRemoved   false，doDie()       true
                return;
            }
            mRemoved = true;
            if (mAdded) { //     window          ！     detach  
                dispatchDetachedFromWindow();
            }

            if (mAdded && !mFirst) {
                destroyHardwareRenderer(); //       

                if (mView != null) {
                    int viewVisibility = mView.getVisibility();
                    boolean viewVisibilityChanged = mViewVisibility != viewVisibility;
                    if (mWindowAttributesChanged || viewVisibilityChanged) { //   window            

                        try {
                            if ((relayoutWindow(mWindowAttributes, viewVisibility, false)
                                    & WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) {
                                mWindowSession.finishDrawing(mWindow);
                            }
                        } catch (RemoteException e) {
                        }
                    }

                    mSurface.release(); //     
                }
            }

            mAdded = false; //     
        }
        WindowManagerGlobal.getInstance().doRemoveView(this);
    }

WindowManager Global.java

void doRemoveView(ViewRootImpl root) {
        synchronized (mLock) {
            final int index = mRoots.indexOf(root); 
            if (index >= 0) {
                mRoots.remove(index);//  ViewRootImpl     
                mParams.remove(index); //         
                final View view = mViews.remove(index); //      view
                mDyingViews.remove(view);//             view
            }
        }
        if (ThreadedRenderer.sTrimForeground && ThreadedRenderer.isAvailable()) {
            doTrimForeground();
        }
    }

dispatch DetachedFrom Window()関数を見に来てください.

void dispatchDetachedFromWindow() {
        if (mView != null && mView.mAttachInfo != null) {
            mAttachInfo.mTreeObserver.dispatchOnWindowAttachedChange(false);
            mView.dispatchDetachedFromWindow(); //   view detach  ！       onDetachedFromWidow()     onDetachedFromWindowInternal()  
        }

        // ...

        destroyHardwareRenderer();

        // ...

        mSurface.release();

        // ...
        try {
            mWindowSession.remove(mWindow);
        } catch (RemoteException e) {
        }

        // ...

        mDisplayManager.unregisterDisplayListener(mDisplayListener);

        unscheduleTraversals();
    }

再度IPCでremove()関数を呼び出します.
Session.java

public void remove(IWindow window) {
        mService.removeWindow(this, window);
    }

WMS.java

public void removeWindow(Session session, IWindow client) {
        synchronized(mWindowMap) {
            WindowState win = windowForClientLocked(session, client, false);
            if (win == null) {
                return;
            }
            removeWindowLocked(win);
        }
    }

void removeWindowLocked(WindowState win) {
        removeWindowLocked(win, false);
    }

void removeWindowLocked(WindowState win, boolean keepVisibleDeadWindow) {
        win.mWindowRemovalAllowed = true;
        // ...

        boolean wasVisible = false;
        // ...

        removeWindowInnerLocked(win);
        // ...
    }

removewindowInner Locked(win);方法の内部分析はしばらく停止します!!