flutter_widget_offset

Description:

flutter widget offset

flutter-widget-offset #
一个类库，用于获取和观察 widget 到根布局边缘的偏移量。
此类库也适用于对话框（showDialog）。
A class library for obtaining and listening the offset of the widget to the edge of the root layout.
This type of library is also suitable for dialogs(showDialog).

Support #

onChanged: Support monitoring the offset of widgets relative to the edge of the root layout.
onKeyboard: Support monitoring soft keyboard status changes (display and hide).

Use OffsetDetector #
Use OffsetDetector directly to get the offset of the widget to the edge of the root layout.
final OffsetDetectorController? _controller = OffsetDetectorController();

OffsetDetector(
controller: _controller,
onChanged: (Size size, EdgeInsets offset, EdgeInsets rootPadding) {
print("The widget size: ${size.width}, ${size.height}");
print(
"The offset to edge of root(ltrb): ${offset.left}, ${offset.top}, ${offset.right}, ${offset.bottom}");
print(
"the root padding: ${rootPadding.left}, ${rootPadding.top}, ${rootPadding.right}, ${rootPadding.bottom}");
},
child: TextField(
style: textFieldStyle,
onChanged: (value) => _controller.notifyStateChanged(),
));
copied to clipboard
Use OffsetChangeObserver #
Use OffsetChangeObserver to observe the offset of the widget to the edge of the root layout.
class OffsetDetector extends StatefulWidget {
OffsetDetector({Key? key}) : super(key: key);

@override
State<StatefulWidget> createState() {
return _OffsetDetectorState();
}
}

class _OffsetDetectorState extends State<OffsetDetector>
with WidgetsBindingObserver {
late OffsetChangeObserver _observer;

@override
Widget build(BuildContext context) {
return TextField();
}

void onChanged(Size size, EdgeInsets offset, EdgeInsets rootPadding) {
print("The widget size: ${size.width}, ${size.height}");
print(
"The offset to edge of root(ltrb): ${offset.left}, ${offset.top}, ${offset.right}, ${offset.bottom}");
print(
"the root padding: ${rootPadding.left}, ${rootPadding.top}, ${rootPadding.right}, ${rootPadding.bottom}");
}

@override
void initState() {
super.initState();
WidgetsBinding.instance!.addObserver(this);
_observer =
OffsetChangeObserver(context: context, onChanged: this.onChanged);
_observer.onInitState();
}

@override
void didChangeMetrics() {
super.didChangeMetrics();
_observer.onChangeMetrics();
}

@override
void didChangeDependencies() {
super.didChangeDependencies();
_observer.onChangeDependencies();
}

@override
void dispose() {
_observer.onDispose();
WidgetsBinding.instance!.removeObserver(this);
super.dispose();
}
}
copied to clipboard
Example #
see widget offset change example