Android 4.4 如何禁止状态栏下拉

代码路径：
frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelBar.java
在PanelBar.java文件中onTouchEvent()方法中把startOpeningPanel(panel)方法屏蔽掉，就可以实现屏蔽掉状态栏可以下拉

@Override
public boolean onTouchEvent(MotionEvent event) {
    // Allow subclasses to implement enable/disable semantics
    if (!panelsEnabled()) {
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            Log.v(TAG, String.format("onTouch: all panels disabled, ignoring touch at (%d,%d)",
                    (int) event.getX(), (int) event.getY()));
        }
        return false;
    }

    // figure out which panel needs to be talked to here
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        final PanelView panel = selectPanelForTouch(event);
        if (panel == null) {
            // panel is not there, so we'll eat the gesture
            Log.v(TAG, String.format("onTouch: no panel for touch at (%d,%d)",
                    (int) event.getX(), (int) event.getY()));
            mTouchingPanel = null;
            return true;
        }
        boolean enabled = panel.isEnabled();
        if (DEBUG) LOG("PanelBar.onTouch: state=%d ACTION_DOWN: panel %s %s", mState, panel,
                (enabled ? "" : " (disabled)"));
        if (!enabled) {
            // panel is disabled, so we'll eat the gesture
            Log.v(TAG, String.format(
                    "onTouch: panel (%s) is disabled, ignoring touch at (%d,%d)",
                    panel, (int) event.getX(), (int) event.getY()));
            mTouchingPanel = null;
            return true;
        }
        //startOpeningPanel(panel);
    }
    final boolean result = mTouchingPanel != null
            ? mTouchingPanel.onTouchEvent(event)
            : true;
    return result;
}

// called from PanelView when self-expanding, too
public void startOpeningPanel(PanelView panel) {
    if (DEBUG) LOG("startOpeningPanel: " + panel);
    mTouchingPanel = panel;
    mPanelHolder.setSelectedPanel(mTouchingPanel);
    for (PanelView pv : mPanels) {
        if (pv != panel) {
            pv.collapse();
        }
    }
}