我面臨着ExpandableListView的一個大問題。 我的目標是讓用戶改變項目的位置到這個單一的選擇擴展列表視圖:將選中的項目移動到可擴展列表視圖
當用戶點擊一個項目,該項目成爲檢查,並顯示上下文操作欄。 所以用戶可以向上或向下移動一個項目這樣:
工作正常(它是基於在一個ArrayList互換位置,我已經實現了向上/向下移動的功能,這就是的數據源我的BaseExpandableListAdapter,並通知UI的更改)。不幸的是,當我移動一個選中的項目,它失去了檢查狀態......如果我將項目移出可見範圍(在示例中,在「鎖定」之後或「附件」視圖之前)expandablelistview不滾動到新的位置。
我該如何做到這一點?
下面,我「moveDownFocusedItem()」編碼到我的自定義適配器類:
//This class is ok!
//Contains Group and Child position of an ExpandableListView
public class Position{
int GroupPosition;
int ChildPosition;
public boolean isChild(){
return (ChildPosition != AbsListView.INVALID_POSITION);
}
public Position getPreviousPosition(){
if(ChildPosition==AbsListView.INVALID_POSITION)
if(GroupPosition>0)
return new Position(GroupPosition-1);
else
return null;
else
if(ChildPosition>0)
return new Position(GroupPosition, ChildPosition-1);
else
return null;
}
public Position getNextPosition(){
if(ChildPosition==AbsListView.INVALID_POSITION)
if(GroupPosition<_fieldConfigurationList.size()-1)
return new Position(GroupPosition+1);
else
return null;
else
if(ChildPosition<_fieldConfigurationList.get(GroupPosition).getChildren().size()-1)
return new Position(GroupPosition, ChildPosition+1);
else
return null;
}
public Position(int groupPosition){
this.GroupPosition = groupPosition;
this.ChildPosition = AbsListView.INVALID_POSITION;
}
public Position(int groupPosition, int childPosition){
this.GroupPosition = groupPosition;
this.ChildPosition = childPosition;
}
}
public void moveDownFocusedItem(){
//This function returns the next position to move to
//(_focusedPosition is the current checked item position)
Position nextPosition = this._focusedPosition.getNextPosition();
//Swap ArrayList (This works!)
if(nextPosition!=null){
Collections.swap(this._fieldConfigurationList, //that's my datasource
this._focusedPosition.GroupPosition, //Start position for swapping
nextPosition.GroupPosition); //Destination position for swapping
//Set the new focused position (This works!)
this._focusedPosition = nextPosition;
//TODO:
//Now i have to call "SetItemChecked()" method to uncheck old focused position and check the new one.
//How to do it? How can i get the required "position" argument from _focusedPosition.GroupPosition and _focusedPosition.ChildPosition?
//And also...if the focused view has moved to an invisible position (such as the end of the expandablelistview) how can i scroll
//to this position?
//Notify changes (This works!)
this.notifyDataSetChanged();
}
}