如何在Android中使用ResourceCursorTreeAdapter扩展和折叠组视图？

Question

如何将ResourceCursorTreeAdapter与以下构造函数一起使用？

ResourceCursorTreeAdapter(Context context, Cursor cursor, int collapsedGroupLayout, int expandedGroupLayout, int childLayout)

我正在尝试使用它如下:

_resultsCursorTreeAdapter = new ResourceCursorTreeAdapter(_resultsList.getContext(), _dbAdapter.getAllGroups(), 
        R.layout.timing_group_view_collapsed, R.layout.timing_group_view_expanded, R.layout.timing_result_view) {

 @Override
 protected Cursor getChildrenCursor(Cursor groupCursor) {
  // Given the group, we return a cursor for all the children within that group 
  int groupId = groupCursor.getInt(0);
  Cursor childCursor = _dbAdapter.getContractionsForGroup(groupId);
  return childCursor;
 }

 @Override
 protected void bindGroupView(View groupView, Context context, Cursor cursor,
     boolean isExpanded) {

  TimingGroupView timingGroupItem =  null;
  if(groupView instanceof LinearLayout){
   Log.i("TimingGroupView", "Has Header");
   LinearLayout layout = (LinearLayout)groupView;

   timingGroupItem = (TimingGroupView) layout.getChildAt(0);
  } else{
   Log.i("TimingGroupView", "No Header");
   timingGroupItem = (TimingGroupView) groupView;
  } 
 ...

如果扩展了组节点,我希望组节点包含表的标题,每个表都保存在子节点中.timing_group_view_expanded.xml和timing_group_view_collapsed.xml显示在此问题的底部.出于某种原因,无论组节点是展开还是折叠,都不会使用group_view_expanded.我用错了吗？有没有其他人能够使用此构造函数获取ResourceCursorTreeAdapter？

timing_group_view_expanded.xml如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="@+id/timing_group_view"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="wrap_content" xmlns:android="http://schemas.android.com/apk/res/android"
 android:background="@color/header_timing_color">

 <com.contractiontracker.TimingGroupView
  android:id="@+id/timing_group_item" xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent" android:layout_height="wrap_content"
  android:layout_marginLeft="30px" android:padding="10dp"
  android:scrollbars="vertical" 
  android:fadingEdge="vertical" 
  android:background="@color/header_timing_color"
  android:textColor="@color/text_color"/>

 <com.contractiontracker.RowLayout android:id="@+id/timing_group_view"
  android:orientation="horizontal" android:layout_width="fill_parent"
  android:layout_height="wrap_content" xmlns:android="http://schemas.android.com/apk/res/android"
  android:background="@color/header_color" android:textColor="@color/text_color">

  <TextView android:id="@+id/interval_header"
   android:layout_width="fill_parent" android:layout_height="wrap_content"
   android:text="Interval" android:layout_weight="1"
   android:layout_gravity="left|bottom" android:gravity="center" 
   android:textColor="@color/text_color">
  </TextView>
  <TextView android:id="@+id/duration_header"
   android:layout_width="fill_parent" android:layout_height="wrap_content"
   android:text="Duration" android:layout_weight="1"
   android:layout_gravity="center_horizontal|bottom" android:gravity="center"
   android:textColor="@color/text_color"
   >
  </TextView>
  <TextView android:id="@+id/intensity_header"
   android:layout_width="fill_parent" android:layout_height="wrap_content"
   android:text="Intensity" android:layout_weight="1"
   android:layout_gravity="right|bottom" android:gravity="center"
   android:textColor="@color/text_color"
   >
  </TextView>
</com.contractiontracker.RowLayout>
</LinearLayout>

timing_group_view_collapsed.xml如下所示:

<?xml version="1.0" encoding="utf-8"?>
<com.contractiontracker.TimingGroupView 
  android:id="@+id/timing_group_item"
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:layout_marginLeft="50px" 
 android:padding="10dp"
 android:scrollbars="vertical"
 android:textColor="@color/text_color"
 android:fadingEdge="vertical"/>

Answer 1

问题是ResourceCursorTreeAdapter 只在创建视图时创建正确的布局.因此,如果一个组被折叠或展开,newGroupView()则不会再次调用,因此传递给构造函数的不同组布局不会按预期使用.

当为正常和最后一个孩子使用不同的布局时,子布局存在同样的问题.它发生在那里甚至没有改变数据!重新扩展组后,第一个具有页脚布局,反之亦然.完全随机而不是基于列表中的位置.

如亚历山大·ö显示在他的实施例,可以通过随时调用解决这个newGroupView()在getGroupView方法(以及getChildView如果使用针对不同的布局分别地).

为了避免总是创建新视图,我尝试了一种适合我的情况的不同方法:

• 将不同的id添加到用于组/子视图的布局的根元素

• 将这些view-id存储为我的适配器的int成员:

  // Get the view ids for comparison
  View view = newGroupView(mContext, null, false, null);
  mCollapsedGroupLayoutViewId = view.getId();
  view = newGroupView(mContext, null, true, null);
  mExpandedGroupLayoutViewId = view.getId();
  
  view = newChildView(mContext, null, false, null);
  mChildLayoutViewId = view.getId();
  view = newChildView(mContext, null, true, null);
  mLastChildLayoutViewId = view.getId();
  

• getGroupView的实现(和getChildView模拟):

  public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
          Cursor cursor = getGroup(groupPosition);
          if (cursor == null) {
              throw new IllegalStateException("this should only be called when the cursor is valid");
          }
  
          View v;
          if (convertView == null 
            || (isExpanded && convertView.getId() == mCollapsedGroupLayoutViewId) 
            || (!isExpanded && convertView.getId() == mExpandedGroupLayoutViewId)) {
              v = newGroupView(mContext, cursor, isExpanded, parent);
          }
          else {
              v = convertView;
          }
          bindGroupView(v, mContext, cursor, isExpanded);
          return v;
  }