Java 单击可展开的Listview图像更改？

我有下面的代码运行完美。当用户单击某个组时，该组会展开由于状态更改而导致的图像更改。xml文件也在下面。我遇到的问题是，当我单击一个子元素时，它会启动一个新的活动，但就在您可以看到图像的状态更改为“组已关闭”之前。使用“后退”箭头时，即使组仍处于展开状态，图像也确实返回到关闭状态。有人能解释一下吗

private static final int[] EMPTY_STATE_SET = {};
private static final int[] GROUP_EXPANDED_STATE_SET = {android.R.attr.state_expanded};
private static final int [] [] GROUP_STATE_SETS = {
    EMPTY_STATE_SET, //0
    GROUP_EXPANDED_STATE_SET //1
};

           Cursor groupCursor = checkDB.rawQuery("SELECT * FROM TABLE", null);
            mscta = new MySimpleCursorTreeAdapter(
                                                    this,
                                                    groupCursor,
                                                    R.layout.listGroup,
                                                    new String[] {"group"},
                                                    new int[] {R.id.group},
                                                    R.layout.listChildren,
                                                    new String[] {"child"},
                                                    new int[] {R.id.Child}) {
                @Override
                public View getGroupView (int groupPosition,
                        boolean isExpanded,
                        View convertView,
                        ViewGroup parent) {

                        View v = super.getGroupView( groupPosition, isExpanded, convertView, parent);
                        View ind = v.findViewById(R.id.explist_indicator);
                        if(ind != null){
                            ImageView indicator = (ImageView) ind;
                            indicator.setVisibility( View.VISIBLE );
                            int stateSetIndex = ( isExpanded ? 1:0);
                            Drawable drawable = indicator.getDrawable();
                            drawable.setState(GROUP_STATE_SETS[stateSetIndex]);
                        }
                        return v;
                    }
            };

XML explist_indicator.XML

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:state_expanded="true"
        android:drawable="@drawable/minus" />
    <item
        android:drawable="@drawable/plus" />
</selector>

---

您可以通过调用onRestart（）来更新listview，当u再次进入活动时将调用它，因此您可以更新列表视图，但您会发现groupview已关闭