Flutter Tensorflowlite Object Detection - flutter

Question

I am working on an object recognition application with Flutter.
When the object is detected, it shows on the screen by covering it with container.
I want to convey the title of the detected object to the user audibly. It takes the title from the list named Results and displays it as a map.
I got it to speak the specified texts with TextToSpeech, but I don't know how to do it in real time.
List<Widget> _renderBoxes() {
return widget.results.map((re) {
var _x = re["rect"]["x"];
var _w = re["rect"]["w"];
var _y = re["rect"]["y"];
var _h = re["rect"]["h"];
var scaleW, scaleH, x, y, w, h;
if (widget.screenH / widget.screenW >
widget.previewH / widget.previewW) {
scaleW = widget.screenH / widget.previewH * widget.previewW;
scaleH = widget.screenH;
var difW = (scaleW - widget.screenW) / scaleW;
x = (_x - difW / 2) * scaleW;
w = _w * scaleW;
if (_x < difW / 2) w -= (difW / 2 - _x) * scaleW;
y = _y * scaleH;
h = _h * scaleH;
} else {
scaleH = widget.screenW / widget.previewW * widget.previewH;
scaleW = widget.screenW;
var difH = (scaleH - widget.screenH) / scaleH;
x = _x * scaleW;
w = _w * scaleW;
y = (_y - difH / 2) * scaleH;
h = _h * scaleH;
if (_y < difH / 2) h -= (difH / 2 - _y) * scaleH;
}
return Positioned(
left: math.max(0, x),
top: math.max(0, y),
width: w,
height: h,
child: Container(
padding: const EdgeInsets.only(top: 5.0, left: 5.0),
decoration: BoxDecoration(
border: Border.all(
color: Colors.amber,
width: 1.0,
),
),
child: Text(
"${re["detectedClass"]} ${(re["confidenceInClass"] * 100).toStringAsFixed(0)}%",
style: const TextStyle(
color: Colors.amber,
fontSize: 14.0,
fontWeight: FontWeight.bold,
),
),
),
);
}).toList();
}
The method I tried is
into the build
_res = Map.fromIterable(widget.results, value: (e) => e.detectedClass)
as String;
add _res value
#override
void initState() {
super.initState();
_textToSpeech.speak(_res);
}
I called it inside the method but it gave an error: "type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'String' in type cast" and "Each child must be laid out exactly once.
"