I can't search in listview, results are wrong - flutter

Question

class _HomeScreenState extends State<HomeScreen> {
TextEditingController _textController = TextEditingController();
var list = List<Widget>();
var channels = ChannelService.channels;
....
buildBody() {
return Container(
child: Column(children: [
searchArea(),
Expanded(
flex: 6,
child: ListView.builder(
itemCount: channels.length,
itemBuilder: (BuildContext context, int index){
return ChannelService.getChannelWidget(channels[index]);
},
)
),
ControlPanel()
]));
}
searchArea() {
return Container(
color: Colors.black87,
height: 45,
padding: EdgeInsets.only(left: 10, right: 10, top: 5, bottom: 5),
child: TextField(
cursorColor: Colors.black,
decoration: InputDecoration(
filled: true,
fillColor: Colors.white,
contentPadding: EdgeInsets.only(left: 10),
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(50),
borderSide: BorderSide(color: Colors.black87, width: 3)),
focusedBorder: OutlineInputBorder(
borderRadius: BorderRadius.circular(50),
borderSide: BorderSide(color: Colors.red, width: 2)),
hintText: "Aramak için yazın.",
hintStyle: TextStyle(color: Colors.black),
suffixIcon: Icon(
Icons.search,
size: 30,
color: Colors.black,
)),
controller: _textController,
onChanged: onChanged,
),
);
}
onChanged(String value) {
if(value.isNotEmpty){
setState(() {
channels = ChannelService.channels
.where((item) => item.name.toLowerCase().contains(value.toLowerCase()))
.toList();
});
}
else{
setState(() {
channels = ChannelService.channels;
});
}
}
}
Results:This
I've been dealing with this error for a long time. What I want to do is a simple search operation. However, I could not succeed. The word I want to search for and the result are different. Please help me.
Where am i doing wrong?
Another problem. My app was started listview is empty.
getChannelWidget:
static Widget getChannelWidget(Channel channel) {
return ChannelListWidget(
id: channel.id,
name: channel.name,
image: channel.image,
categories: channel.categories.toList(),
url: channel.url,
listened: channel.listened,
favorite: isFavorite(channel.id)
);