Android 设置window信息到inputflinger

在Android InputDispatch事件派发-＞选择目标窗口一文中我们分析了Android 根据Wms的window信息来派发事件到window对应的应用程序，今天我们来分析下Android如何更新window信息到inputflinger。
当window信息发生变化的时候Wms需要更新window的信息到inputflinger， Android使用InputMonitor.java类来完成操作，InputMonitor 更新window的函数为updateInputWindowsLw。 我们在在Android InputDispatch事件派发-＞选择目标窗口一文中看到InputDispatcher使用InputWindowHandle代表一个Window，在Wms中由于是java代码，使用InputWindowHandle java类作为inputflinger中InputWindowHandle的对等体。

public final class InputWindowHandle {
 // Pointer to the native input window handle.
    // This field is lazily initialized via JNI.
    @SuppressWarnings("unused")
    private long ptr;

    // The input application handle.
    public final InputApplicationHandle inputApplicationHandle;

    // The window manager's window state.
    public final Object windowState;

    // The input channel associated with the window.
    public InputChannel inputChannel;

    // The window name.
    public String name;

    // Window layout params attributes.  (WindowManager.LayoutParams)
    public int layoutParamsFlags;
    public int layoutParamsType;

    // Dispatching timeout.
    public long dispatchingTimeoutNanos;

    // Window frame.
    public int frameLeft;
    public int frameTop;
    public int frameRight;
    public int frameBottom;

    // Global scaling factor applied to touch events when they are dispatched
    // to the window
    public float scaleFactor;

    // Window touchable region.
    public final Region touchableRegion = new Region();

    // Window is visible.
    public boolean visible;

    // Window can receive keys.
    public boolean canReceiveKeys;

    // Window has focus.
    public boolean hasFocus;

    // Window has wallpaper.  (window is the current wallpaper target)
    public boolean hasWallpaper;

    // Input event dispatching is paused.
    public boolean paused;

    // Window layer.
    public int layer;

    // Id of process and user that owns the window.
    public int ownerPid;
    public int ownerUid;

    // Window input features.
    public int inputFeatures;

    // Display this input is on.
    public final int displayId;

}

Inputflinger和wms中的InputWindowHandle提供的信息是一致的。

Wms把每个屏幕抽象为DisplayContent，每个屏幕上打开的窗口按照层级关系存储再WindowList的集合中，每个Window用WindowState描述状态，WindowState中的mInputWindowHandle则描述了输入相关的窗口信息。updateInputWindowsLw函数就是将窗口信息告知给inputflinger的函数。

 /* Updates the cached window information provided to the input dispatcher. */
    public void updateInputWindowsLw(boolean force) {
        if (!force && !mUpdateInputWindowsNeeded) {
            return;
        }
        mUpdateInputWindowsNeeded = false;

        if (false) Slog.d(WindowManagerService.TAG, ">>>>>> ENTERED updateInputWindowsLw");

        // Populate the input window list with information about all of the windows that
        // could potentially receive input.
        // As an optimization, we could try to prune the list of windows but this turns
        // out to be difficult because only the native code knows for sure which window
        // currently has touch focus.
        boolean disableWallpaperTouchEvents = false;

        // If there's a drag in flight, provide a pseudowindow to catch drag input
        final boolean inDrag = (mService.mDragState != null);
        if (inDrag) {
            if (WindowManagerService.DEBUG_DRAG) {
                Log.d(WindowManagerService.TAG, "Inserting drag window");
            }
            final InputWindowHandle dragWindowHandle = mService.mDragState.mDragWindowHandle;
            if (dragWindowHandle != null) {
                 // 如果当前正在拖动窗口，将拖动处理的InputHandler添加到mInputWindowHandles中
                addInputWindowHandleLw(dragWindowHandle);
            } else {
                Slog.w(WindowManagerService.TAG, "Drag is in progress but there is no "
                        + "drag window handle.");
            }
        }

        boolean addInputConsumerHandle = mService.mInputConsumer != null;

        // Add all windows on the default display.
        final int numDisplays = mService.mDisplayContents.size();
        // 遍历所有的屏幕下的所有窗口
        for (int displayNdx = 0; displayNdx < numDisplays; ++displayNdx) {
            WindowList windows = mService.mDisplayContents.valueAt(displayNdx).getWindowList();
            for (int winNdx = windows.size() - 1; winNdx >= 0; --winNdx) {
                final WindowState child = windows.get(winNdx);
                final InputChannel inputChannel = child.mInputChannel;
                final InputWindowHandle inputWindowHandle = child.mInputWindowHandle;
                if (inputChannel == null || inputWindowHandle == null || child.mRemoved) {
                    // Skip this window because it cannot possibly receive input.
                    // 跳过不能处理input事件的窗口
                    continue;
                }
                // 添加mInputConsumer到mInputWindowHandles列表，注意会根据层级添加到合适的位置
                if (addInputConsumerHandle
                        && inputWindowHandle.layer <= mService.mInputConsumer.mWindowHandle.layer) {
                    addInputWindowHandleLw(mService.mInputConsumer.mWindowHandle);
                    addInputConsumerHandle = false;
                }

                final int flags = child.mAttrs.flags;
                final int privateFlags = child.mAttrs.privateFlags;
                final int type = child.mAttrs.type;

                final boolean hasFocus = (child == mInputFocus);
                final boolean isVisible = child.isVisibleLw();
                if ((privateFlags
                        & WindowManager.LayoutParams.PRIVATE_FLAG_DISABLE_WALLPAPER_TOUCH_EVENTS)
                            != 0) {
                    // 如果上面有window进制将事件发送给墙纸窗口，则后续都不允许将事件发送给壁纸窗口
                    disableWallpaperTouchEvents = true;
                }
                final boolean hasWallpaper = (child == mService.mWallpaperTarget)
                        && (privateFlags & WindowManager.LayoutParams.PRIVATE_FLAG_KEYGUARD) == 0
                        && !disableWallpaperTouchEvents;
                final boolean onDefaultDisplay = (child.getDisplayId() == Display.DEFAULT_DISPLAY);

                // If there's a drag in progress and 'child' is a potential drop target,
                // make sure it's been told about the drag
                if (inDrag && isVisible && onDefaultDisplay) {
                    mService.mDragState.sendDragStartedIfNeededLw(child);
                }
                // 添加window到mInputWindowHandles
                addInputWindowHandleLw(inputWindowHandle, child, flags, type, isVisible, hasFocus,
                        hasWallpaper);
            }
        }

        // 提交窗口信息到inputflinger
        // Send windows to native code.
        mService.mInputManager.setInputWindows(mInputWindowHandles);

        // Clear the list in preparation for the next round.
        // 清空
        clearInputWindowHandlesLw();

        if (false) Slog.d(WindowManagerService.TAG, "<<<<<<< EXITED updateInputWindowsLw");
    }

updateInputWindowsLw函数整个流程不太复杂，整个过程主要做的工作就是按照从高到低的顺序收集窗口信息到mInputWindowHandles描述的数组中，添加窗口到mInputWindowHandles使用的函数为addInputWindowHandleLw函数。当收集完所有窗口信息后，通过mService.mInputManager.setInputWindows(mInputWindowHandles)同步窗口信息给inputflinger。最后调用clearInputWindowHandlesLw()函数来清空mInputWindowHandles，方便下一轮收集。在收集window的过程中有两个特殊的window，第一个是mService.mDragState.mDragWindowHandle，用于处理window拖动的情况。另外一个是mService.mInputConsumer.mWindowHandle，处于在应用进入全屏模式下拦截事件。比如全屏播放视频的时候，触摸窗口会将导航栏显示出来，就是通过这个window来接收的输入事件，进行处理。

本文地址：https://blog.csdn.net/woai110120130/article/details/112642294