我正在尝试在应该创建音频波形的容器行顶部创建一个范围 slider ,但我什至不知道从哪里开始...
主要问题是范围 slider 位于容器行的正上方,它应该在“选定”部分更改它们的颜色。
这是我目前拥有的:
创建图像和细节的代码。
class BeatLyricsPage extends StatefulWidget {
final Beat beat;
BeatLyricsPage(this.beat);
@override
_BeatLyricsPageState createState() => _BeatLyricsPageState(beat);
}
class _BeatLyricsPageState extends State<BeatLyricsPage> {
final Beat beat;
final _kPicHeight = 190.0;
// used in _buildPageHeading to add the beat key and beat bpm
Widget _buildBeatInfoItem(String text) => DecoratedBox(
decoration: BoxDecoration(
border: Border.all(color: MyColor.white, width: 1.0),
borderRadius: BorderRadius.circular(4.0),
),
child: Padding(
padding: EdgeInsets.symmetric(vertical: 3.0, horizontal: 12.0),
child: Text(text, style: TextStyle(color: MyColor.white, fontSize: 10.0, fontWeight: FontWeight.w600)),
),
);
final _kAudioControlsWidth = 180.0;
final _kAudioControlsHeight = 36.0;
final _kAudioControlsMainButtonSize = 56.0;
Widget _buildAudioControls(BuildContext context) => Positioned(
left: (MediaQuery.of(context).size.width / 2) - (_kAudioControlsWidth / 2),
top: _kPicHeight - (_kAudioControlsHeight / 2),
child: Stack(
overflow: Overflow.visible,
children: [
Container(
width: _kAudioControlsWidth,
height: _kAudioControlsHeight,
decoration: BoxDecoration(color: MyColor.darkGrey, borderRadius: BorderRadius.circular(100.0)),
padding: EdgeInsets.symmetric(horizontal: LayoutSpacing.sm),
child: Row(
children: [
CButtonLike(beatId: beat.id),
Spacer(),
GestureDetector(
behavior: HitTestBehavior.opaque,
child: Icon(BeatPulseIcons.cart),
onTap: () => Navigator.push(context, MaterialPageRoute(builder: (_) => LicenseOptionsPage(beat))),
),
],
),
),
// ****** MAIN BUTTON (Play/Pause) ******
Positioned(
left: (_kAudioControlsWidth / 2) - (_kAudioControlsMainButtonSize / 2),
top: (_kAudioControlsHeight - _kAudioControlsMainButtonSize) / 2,
child: Container(
height: _kAudioControlsMainButtonSize,
width: _kAudioControlsMainButtonSize,
decoration: BoxDecoration(
gradient: LinearGradient(begin: Alignment.topLeft, colors: [MyColor.primary, Color(0xFFf80d0a)]),
borderRadius: BorderRadius.circular(100.0)),
child: CButtonPlay(),
),
)
],
),
);
Widget _buildWaveForm() {
// creates a random list of doubles, "fake data"
var rng = Random();
final List waveFormData = [];
for (var i = 0; i < 90; i++) {
waveFormData.add(rng.nextInt(45).toDouble());
}
// player bloc
final playerBloc = BlocProvider.getPlayerBloc(context);
// renders
return Container(
height: _kPicHeight,
padding: EdgeInsets.symmetric(vertical: LayoutSpacing.xxxl),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.end,
children: [
// current playing second
StreamBuilder<double>(
stream: playerBloc.playingSecond,
initialData: 0.0,
builder: (_, playingSecondSnapshot) {
// current beat playing
return StreamBuilder<Beat>(
stream: playerBloc.playingBeat,
builder: (_, playingBeatSnapshot) {
final playingBeat = playingBeatSnapshot.data;
// if the beat playing is the same as the beat selected for the lyrics, show playing seconds
if (playingBeat?.id == beat.id)
return Text(secondsToTime(playingSecondSnapshot.data), style: MyFontStyle.sizeXxs);
// otherwise show 0:00
else
return Text(secondsToTime(0), style: MyFontStyle.sizeXxs);
},
);
},
),
SizedBox(width: LayoutSpacing.xs),
Row(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.end,
children: waveFormData
.map((waveFormDataIndex) => Container(
height: waveFormDataIndex > 5.0 ? waveFormDataIndex : 5.0,
width: 2,
color: MyColor.white,
margin: EdgeInsets.only(right: 1),
))
.toList(),
),
SizedBox(width: LayoutSpacing.xs),
Text(secondsToTime(beat.length), style: MyFontStyle.sizeXxs),
],
),
);
}
Widget _buildPageHeading(BuildContext context, {@required String imageUrl}) => Stack(
children: [
Column(
children: [
Hero(
tag: MyKeys.makePlayerCoverKey(beat.id),
child: Opacity(
opacity: 0.3,
child: Container(
height: _kPicHeight,
decoration: BoxDecoration(
image: DecorationImage(image: CachedNetworkImageProvider(imageUrl), fit: BoxFit.cover),
),
),
),
),
Container(color: MyColor.background, height: LayoutSpacing.xl)
],
),
Padding(
padding: EdgeInsets.all(LayoutSpacing.xs),
child: Row(
mainAxisAlignment: MainAxisAlignment.end,
children: [
_buildBeatInfoItem(beat.key),
SizedBox(width: 4.0),
_buildBeatInfoItem('${beat.bpm} BPM'),
],
),
),
_buildAudioControls(context),
_buildWaveForm(),
],
);
}
最佳答案
要创建自定义范围 slider ,您可以使用 GestureRecognizer并将每个 slider 的位置保存在 StatefulWidget 内的变量中.要确定索引为 i 的条是否在范围内,您可以将限制器的像素位置(bar1
&bar2
划分为下面的来源)通过条的宽度并将其与 i 进行比较。
很遗憾,我无法使用您的代码示例。相反,我创建了一个最低限度的示例,如下所示。如果您花一点时间阅读,我相信您可以将其转移到您的应用程序中。
import 'dart:math';
import 'package:flutter/material.dart';
List<int> bars = [];
void main() {
// generate random bars
Random r = Random();
for (var i = 0; i < 50; i++) {
bars.add(r.nextInt(200));
}
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Home(),
);
}
}
class Home extends StatefulWidget {
@override
State<StatefulWidget> createState() => HomeState();
}
class HomeState extends State<Home> {
static const barWidth = 5.0;
double bar1Position = 60.0;
double bar2Position = 180.0;
@override
Widget build(BuildContext context) {
int i = 0;
return Scaffold(
body: Center(
child: Stack(
alignment: Alignment.centerLeft,
children: <Widget>[
Row(
crossAxisAlignment: CrossAxisAlignment.center,
mainAxisAlignment: MainAxisAlignment.start,
children: bars.map((int height) {
Color color =
i >= bar1Position / barWidth && i <= bar2Position / barWidth
? Colors.deepPurple
: Colors.blueGrey;
i++;
return Container(
color: color,
height: height.toDouble(),
width: 5.0,
);
}).toList(),
),
Bar(
position: bar2Position,
callback: (DragUpdateDetails details) {
setState(() {
bar2Position += details.delta.dx;
});
},
),
Bar(
position: bar1Position,
callback: (DragUpdateDetails details) {
setState(() {
bar1Position += details.delta.dx;
});
},
),
],
),
),
);
}
}
class Bar extends StatelessWidget {
final double position;
final GestureDragUpdateCallback callback;
Bar({this.position, this.callback});
@override
Widget build(BuildContext context) {
return Padding(
padding: EdgeInsets.only(left: position >= 0.0 ? position : 0.0),
child: GestureDetector(
onHorizontalDragUpdate: callback,
child: Container(
color: Colors.red,
height: 200.0,
width: 5.0,
),
),
);
}
}
https://stackoverflow.com/questions/52987440/
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