Android TaskbarDelegate 屏蔽上滑返回桌面手势

2. 注册并监听任务栈变化

TaskbarDelegate 原本逻辑中就包含了 TaskStackChangeListener 的监听，但是没有 onTaskStackChanged 的重写，只需要加上即可

private boolean mIsHomeGestureBlocked;
private final TaskStackChangeListener mTaskStackListener = new TaskStackChangeListener() {
    @Override
    public void onLockTaskModeChanged(int mode) {
        mSysUiState.setFlag(SYSUI_STATE_SCREEN_PINNING, mode == LOCK_TASK_MODE_PINNED).commitUpdate(mDisplayId);
    }

    @Override
    public void onTaskStackChanged() {
        updateHomeGestureBlockState();
    }
};

private void updateHomeGestureBlockState() {
    boolean shouldBlock = false;
    ActivityManager.RunningTaskInfo runningTask = ActivityManagerWrapper.getInstance().getRunningTask();
    ComponentName topActivity = runningTask == null ? null : runningTask.topActivity;
    shouldBlock = topActivity != null && mHomeBlockingActivities.contains(topActivity);
    if (mIsHomeGestureBlocked != shouldBlock) {
        mIsHomeGestureBlocked = shouldBlock;
        updateSysuiFlags();
    }
}

3. 更新标志位 updateSysuiFlags

private void updateSysuiFlags() {
    android.util.Log.e("maxx", "updateSysuiFlags");
    int a11yFlags = mNavBarHelper.getA11yButtonState();
    boolean clickable = (a11yFlags & SYSUI_STATE_A11Y_BUTTON_CLICKABLE) != 0;
    boolean longClickable = (a11yFlags & SYSUI_STATE_A11Y_BUTTON_LONG_CLICKABLE) != 0;
    
    // 新增修改：
    boolean overviewDisabled = (mDisabledFlags & View.STATUS_BAR_DISABLE_RECENT) != 0 || mIsHomeGestureBlocked;
    boolean homeDisabled = (mDisabledFlags & View.STATUS_BAR_DISABLE_HOME) != 0 || mIsHomeGestureBlocked;
    
    mSysUiState.setFlag(SYSUI_STATE_A11Y_BUTTON_CLICKABLE, clickable)
        .setFlag(SYSUI_STATE_A11Y_BUTTON_LONG_CLICKABLE, longClickable)
        .setFlag(SYSUI_STATE_IME_SHOWING, (mNavigationIconHints & NAVIGATION_HINT_BACK_ALT) != 0)
        .setFlag(SYSUI_STATE_IME_SWITCHER_SHOWING, (mNavigationIconHints & NAVIGATION_HINT_IME_SWITCHER_SHOWN) != 0)
        // 新增修改：
        .setFlag(SYSUI_STATE_OVERVIEW_DISABLED, overviewDisabled)
        .setFlag(SYSUI_STATE_HOME_DISABLED, homeDisabled)
        .setFlag(SYSUI_STATE_BACK_DISABLED, (mDisabledFlags & View.STATUS_BAR_DISABLE_BACK) != 0)
        .setFlag(SYSUI_STATE_NAV_BAR_HIDDEN, !isWindowVisible())
        .setFlag(SYSUI_STATE_ALLOW_GESTURE_IGNORING_BAR_VISIBILITY, allowSystemGestureIgnoringBarVisibility())
        .setFlag(SYSUI_STATE_IMMERSIVE_MODE, isImmersiveMode())
        .commitUpdate(mDisplayId);
}

还有一种思路是在 Launcher 做屏蔽处理，例如在 Launcher3 的源码中处理，在 TouchInteractionService 的 onInputEvent 方法中直接返回即可。

Launcher3/quickstep/src/com/android/quickstep/TouchInteractionService.java
public void onInputEvent(InputEvent ev) {
    if (needInterceptHome()) {
        return;
    }
    ...
}