I have a list of ExpansionTile with a list of ListTile in a Drawer. What I want to achieve is, when I press an ExpansionTile, the another ExpansionTile must be collapsed. I had been stuck with this problem for two days and could not find an answer. Can anybody know how to collapse the ExpansionTile programmatically?

Note:

I don't want to mess up the animation of the widget.

Here is my code,

ListView.builder(
                itemCount: userList.length,
                shrinkWrap: true,
                itemBuilder: (BuildContext context, findex) {
                  return ExpansionTile(
                    key: Key(findex.toString()),
                    title: Text(userList[findex].parentdata[0].title,
                      style: TextStyle(fontSize: 15.0, fontWeight: FontWeight.bold,color: Colors.black),
                    ),
                    onExpansionChanged: (value) {
                    },
                    children: [
                      ListView.builder(
                        itemCount: userList[findex].document.length,
                        shrinkWrap: true,
                        itemBuilder: (BuildContext context, sindex) {
                          return ListTile(
                            title: Text(
                                userList[findex].document[sindex].title,
                              style: TextStyle(fontSize: 15.0, fontWeight: FontWeight.bold,color: Colors.black),
                            ),
                            onTap: () {
                              print(
                                  userList[findex].document[sindex].title);
                            },
                          );
                        },
                      ),
                    ],
                  );
                },
              ),

CodePudding user response：

Try this:

Create a variable: int selected = -1;

And listview:

ListView.builder(
          itemCount: 10,
          shrinkWrap: true,
          itemBuilder: (BuildContext context, findex) {
            return ExpansionTile(
              initiallyExpanded: findex == selected,
              key: Key(selected.toString()),
              title: Text(userList[findex].parentdata[0].title,
                style: TextStyle(fontSize: 15.0, fontWeight: FontWeight.bold,color: Colors.black),
              ),
              onExpansionChanged: (newState) {
                setState(() {
                  selected = findex;
                });
              },
              children: [
                ListView.builder(
                  itemCount: 10,
                  shrinkWrap: true,
                  itemBuilder: (BuildContext context, sindex) {
                    return ListTile(
                      title: Text(
                        userList[findex].document[sindex].title,
                        style: TextStyle(fontSize: 15.0, fontWeight: FontWeight.bold,color: Colors.black),
                      ),
                      onTap: () {
                        print(userList[findex].document[sindex].title);
                      },
                    );
                  },
                ),
              ],
            );
          },
        ),

CodePudding user response：

Try below code

declare one int variable

int selectedTile = -1;

Your widget

ListView.builder(
  key: Key(selectedTile.toString()),
  itemCount: 5,
  itemBuilder: (context, index) {
    return ExpansionTile(
      key: Key(index.toString()),
      initiallyExpanded: index == selectedTile,
      title: Text('ExpansionTile $index'),
      subtitle: Text('Trailing expansion arrow icon'),
      children: [
        ListTile(
          title: Text('This is tile number $index'),
        ),
      ],
      onExpansionChanged: ((newState) {
        if (newState)
          setState(() {
            selectedTile = index;
          });
        else
          setState(() {
            selectedTile = -1;
          });
      }),
    );
  },
);

CodePudding user response：

Use ExpansionPanel widget.

You need to create a variable and maintain the expansion state of expansion panel index.

expansionCallback: (int index, bool isExpanded) {
        setState(() {
          // when any of expansionPanel is Tapped
          // set all expansion to false
          for(int i = 0; i<_data.length; i  ){
            _data[i].isExpanded = false;
          }
          // then set the tapped index to its state
          _data[index].isExpanded = !isExpanded;
        });
      },

Here is an live demo for expansion panel