先重新看看 DisplayContent 類的定義：

class DisplayContent extends RootDisplayArea implements WindowManagerPolicy.DisplayContentInfo {

直接父類為 RootDisplayArea， 而它的定義：

class RootDisplayArea extends DisplayArea.Dimmable {

因此要再看 DisplayArea.Dimmable

1.DisplayArea.Dimmable

作為 DisplayArea 的內(nèi)部靜態(tài)類, 表示可以置灰逾冬，而它實際上是繼承了 DisplayArea

    /**
     * DisplayArea that can be dimmed.
     */
    static class Dimmable extends DisplayArea<DisplayArea> {
        private final Dimmer mDimmer = new Dimmer(this);
        private final Rect mTmpDimBoundsRect = new Rect();

        Dimmable(WindowManagerService wms, Type type, String name, int featureId) {
            super(wms, type, name, featureId);
        }

        @Override
        Dimmer getDimmer() {
            return mDimmer;
        }

        @Override
        void prepareSurfaces() {
            mDimmer.resetDimStates();
            super.prepareSurfaces();
            // Bounds need to be relative, as the dim layer is a child.
            getBounds(mTmpDimBoundsRect);
            mTmpDimBoundsRect.offsetTo(0 /* newLeft */, 0 /* newTop */);

            // If SystemUI is dragging for recents, we want to reset the dim state so any dim layer
            // on the display level fades out.
            if (forAllTasks(task -> !task.canAffectSystemUiFlags())) {
                mDimmer.resetDimStates();
            }

            if (mDimmer.updateDims(getSyncTransaction(), mTmpDimBoundsRect)) {
                scheduleAnimation();
            }
        }
    }

可以看出來祥诽，它的創(chuàng)建實際上依賴父類 DisplayArea 的構(gòu)造函數(shù).
并且類本身的也做為泛型對象..

2. DisplayArea 源碼

用于將 WindowContainer 分組到 DisplayContent 下面的容器譬圣。
DisplayAreas 由 {@link DisplayAreaPolicy} 管理, 可以重寫配置并且可以被束縛。
DisplayAreas 可以包含嵌套的 DisplayAreas.

frameworks/base/services/core/java/com/android/server/wm/DisplayArea.java

類的定義：

/**
 * Container for grouping WindowContainer below DisplayContent.
 *
 * DisplayAreas are managed by a {@link DisplayAreaPolicy}, and can override configurations and
 * can be leashed.
 *
 * DisplayAreas can contain nested DisplayAreas.
 *
 * DisplayAreas come in three flavors, to ensure that windows have the right Z-Order:
 * - BELOW_TASKS: Can only contain BELOW_TASK DisplayAreas and WindowTokens that go below tasks.
 * - ABOVE_TASKS: Can only contain ABOVE_TASK DisplayAreas and WindowTokens that go above tasks.
 * - ANY: Can contain any kind of DisplayArea, and any kind of WindowToken or the Task container.
 *
 * @param <T> type of the children of the DisplayArea.
 */
public class DisplayArea<T extends WindowContainer> extends WindowContainer<T> {

可以看到它的 父類其實也是 WindowContainer雄坪，代表也是一個窗口容器

構(gòu)造方法

    DisplayArea(WindowManagerService wms, Type type, String name, int featureId) {
        super(wms);
        // TODO(display-area): move this up to ConfigurationContainer
        setOverrideOrientation(SCREEN_ORIENTATION_UNSET);
        mType = type;
        mName = name;
        mFeatureId = featureId;
        mRemoteToken = new RemoteToken(this);
        mOrganizerController =
                wms.mAtmService.mWindowOrganizerController.mDisplayAreaOrganizerController;
    }

999
基于 Android 14 源碼. (20230913 codesearch main 分支)

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