Get value from Instance in Flutter - flutter

Question

I am making a search request on the List with the Provider pattern.
List<Device> _devices = [
Device(one: 'Apple', two: 'iphone'),
Device(one: 'Samsung', two: 'Galaxy')
];
And Query is like this
List<Device> queryQuery(String value) {
return _devices
.where((device) => device.one.toLowerCase().contains(value.toLowerCase()))
.toList();
the result I expect to get is iphone when I passed the value Apple.
But the result on the screen that I got is [instance of ‘Device’]
when I code like this
child: Text('${deviceData.getDevice('Apple')}'
I do know I should be using some kind of key using two... but I have no idea :-(

Answer 1

You serialized the wrong object.
What you did end-up being similar to:
Text(Device(one: 'Apple', two: 'iphone').toString());
But you don't want to do Device.toString(). What you want instead is to pass Device.two to your Text.
As such your end result is:
Text('${chordData.chordExpand('Apple').two}')

Answer 2

By the look of [Instance of 'Device'], it seems the function is returning a list so it is a good idea to check if the list is empty or not. if it is not empty, one of the elements is still needed to be selected. I guess it should be Text('${chordData.chordExpand('Apple')[0].two}') in case the list is not empty.
To summarize, use something like this to handle the case when list is empty
// Inside your build method before returning the widget
var l = chordData.chordExpand('Apple'); // Returns a list of devices
String textToWrite; // Here we will store the text that needs to be written
if(l.isEmpty) textToWrite = 'No results'; // If the filter resulted in an empty list
else textToWrite = l[0].two; // l[0] is an instance of a device which has a property called two. You can select any instance from the list provided it exists
return <Your Widget>(
.....
Text(textToWrite),
.....
);