Question

我在片段中有一个runnable。 runnable用于更新文本视图以及使用按钮接收输入。但是程序一旦进入runnable就不会进入。

请帮忙。我究竟做错了什么。谢谢。代码如下。我在runnable中有按钮和textview。

public class TodayFragment extends Fragment {
//initialisations

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

//UI initialisations

Handler mHandler = new Handler();
Runnable mTicker = new Runnable() {
            @Override
            public void run() {

//user interface interactions and updates on screen

    mHandler.postDelayed(mTicker, 1000);


   mTicker.run();

 }

Answer 1

似乎你想每1秒改变一下你的观点。如果你这样说，你应该在runnable方法之外执行你的处理程序。即：

    Handler mHandler = new Handler();
    Runnable mTicker = new Runnable() {
        @Override
        public void run() {

            // user interface interactions and updates on screen
            // if you want to run this handler only once then delete below line
            mHandler.postDelayed(mTicker, 1000);

        }
    };

mHandler.postDelayed(mTicker, 1000);

Answer 2

尝试此更改

mTicker = new Runnable() {
        public void run() {

         //user interface interactions and updates on screen

           mHandler.postDelayed(mTicker, 1000);

        }
    };
    mTicker.run();

Answer 3

这对我有用。

import 'package:flutter/material.dart';
import 'package:flutter_vlc_player/flutter_vlc_player.dart';
void main() {runApp(MyApp());}
class MyApp extends StatelessWidget {
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Raspberry Pi 4 stream'),
    );}}
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;
  _MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
  String _streamUrl;
  VlcPlayerController _vlcPlayerController;
  @override
  void iniState(){
    super.initState();
    _vlcPlayerController = new VlcPlayerController();
  }
  void _incrementCounter() {
    setState(() {
      _streamUrl = 'http://192.168.1.14:8081';
    });
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(widget.title),),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            _streamUrl == null
                ? new Container(
             child: RichText(
               text: TextSpan(
                 children: [
                   TextSpan(
                       text: 'stream closed',
                         style: TextStyle(
                             fontSize: 14,
                             fontWeight: FontWeight.bold,
                             color: Colors.white,
                             background: Paint()..color = Colors.red,
                         ),
                   )
                 ]
               ),),): new VlcPlayer(
              defaultHeight: 480,
              defaultWidth: 640,
              url: _streamUrl,
              controller: _vlcPlayerController,
              placeholder: Container(),
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.play_arrow),
      ),);}}

Runnable Handler不执行内部片段。无法启动可运行的

3 个答案: