windowWindow的操作

WindowManager对Window进行管理，包括了window添加、更新和删除的操作，最终都是交由WMS来进行处理的。窗口的操作分为两大部分，一部分是WindowManager处理部分，另一部分是WMS 处理部分。Window分为三大类，分别是应用程序窗口、子窗口、系统窗口，对于不同类型的窗口添加过程会有所不同，但是WMS对于这三大类的窗口基本是“一 视同仁”的。

1、系统窗口statusbar的添加过程
    ① 添加入口Statusbar::addStatusBarWindow

 

    private void addStatusBarWindow() {
        makeStatusBarView();
        mStatusBarWindowManager = Dependency.get(StatusBarWindowManager.class);
        ...
        mStatusBarWindowManager.add(mStatusBarWindow, getStatusBarHeight());
    }

   ②：StatusBarWindowManager::add

 

 

    /**
     * Adds the status bar view to the window manager.
     *
     * @param statusBarView The view to add.
     * @param barHeight The height of the status bar in collapsed state.
     */
    public void add(View statusBarView, int barHeight) {

        // Now that the status bar window encompasses the sliding panel and its
        // translucent backdrop, the entire thing is made TRANSLUCENT and is
        // hardware-accelerated.
        mLp = new WindowManager.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                barHeight,
                //设置了 TYPE_STATUS_BAR，表示StatusBar视图的窗口类型是状态栏。
                WindowManager.LayoutParams.TYPE_STATUS_BAR,
                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                        | WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING
                        | WindowManager.LayoutParams.FLAG_SPLIT_TOUCH
                        | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH
                        | WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS,
                PixelFormat.TRANSLUCENT);
        mLp.token = new Binder();
        mLp.gravity = Gravity.TOP;
        mLp.softInputMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE;
        mLp.setTitle("StatusBar");
        mLp.packageName = mContext.getPackageName();
        mLp.layoutInDisplayCutoutMode = LAYOUT_IN_DISPLAY_CUTOUT_MODE_ALWAYS;
        mStatusBarView = statusBarView;
        mBarHeight = barHeight;
        //处调用了WindowManager的addView方法，addView方法定义在WindowManager的父类接口ViewManager中，而addView方法则是在WindowManagerImpl中实现的 
        mWindowManager.addView(mStatusBarView, mLp);
        mLpChanged = new WindowManager.LayoutParams();
        mLpChanged.copyFrom(mLp);
    }

 ③：WindowManagerGlobal::addView

 

public void addView(View view, ViewGroup.LayoutParams params,
            Display display, Window parentWindow) {
        //首先会对参数view、params和display进行检查 省略
        final WindowManager.LayoutParams wparams = (WindowManager.LayoutParams) params;
        //如果当前窗口要作为子窗口,就会根据父窗口对子窗口的WindowManager.LayoutParams 类型的 wparams 对象进行相应调整。
        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) {
            .......
            // 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++) {
                    if (mRoots.get(i).mWindow.asBinder() == wparams.token) {
                        panelParentView = mViews.get(i);
                    }
                }
            }
            //创建了ViewRootImp并赋值给root
            root = new ViewRootImpl(view.getContext(), display);
            view.setLayoutParams(wparams);
            mViews.add(view);
            mRoots.add(root);
            mParams.add(wparams);

            // do this last because it fires off messages to start doing things
            try {
                //将窗口和窗口的参数通过setView方法设置到ViewRootImpl中，可见添加窗口这一操作是通过ViewRootImpl来进行的。
                root.setView(view, wparams, panelParentView);
            } catch (RuntimeException e) {
            }
        }
    }

 

 

 

ViewRootImpl 身负了很多职责，主要有以下几点：

· View树的根并管理View树。

· 触发View的测量、布局和绘制。

· 输入事件的中转站。

· 管理Surface。 · 负责与WMS进行进程间通信。

 

ViewRootImpl::setView

public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView) {
        synchronized (this) {
            if (mView == null) {
                mView = view;
         .........
                // Schedule the first layout -before- adding to the window
                // manager, to make sure we do the relayout before receiving
                // any other events from the system.
                requestLayout();
         .......
                if ((mWindowAttributes.inputFeatures
                        & WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHANNEL) == 0) {
                    mInputChannel = new InputChannel();
                }
                
        }
    }

scheduleTraversals实际是View绘制的入口

public void requestLayout() {
        if (!mHandlingLayoutInLayoutRequest) {
                checkThread();
                mLayoutRequested = true;
                scheduleTraversals();
        }
    }