Flutter之listView加载数据 刷新以及加载更多-爱代码爱编程

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_weight_ui/model/home_article_data_entity.dart';
import 'package:flutter_weight_ui/net/RequestUtils.dart';

class ArticlePage extends StatefulWidget{
  @override
  State<StatefulWidget> createState()  =>_ArticlePage();
}
class _ArticlePage extends State<ArticlePage>{
  int page=0;
  static const myPlugin = const MethodChannel("samples.flutter.io/webview");//通道与Android原生交互
  List<HomeArticleDataDataData> articleList = [];
  ScrollController _scrollController = ScrollController();//listView的控制器
  @override
  void initState() {
    getArticleList(page);
    _scrollController.addListener(() {
      if(_scrollController.position.pixels==_scrollController.position.maxScrollExtent){//如果是最后一个item则触发，加载新数据
        page++;
        getArticleList(page);
      }
    });
    super.initState();
  }
  getArticleList(int page) async {
    var result  = await RequestManager.request("https://www.wanandroid.com/article/list/$page/json");
    setState(() {
      HomeArticleDataEntity dataEntity =  HomeArticleDataEntity().fromJson(result);
      if(page==0){
        articleList.clear();
      }
      articleList.addAll(dataEntity.data.datas);
    });
  }
  /// 下拉刷新方法
  Future<Null> _onRefresh() async{
    page=0;
    getArticleList(page);
  }
  ///加载更多

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: Text("文章"),
      ),
      body:
      RefreshIndicator(
        onRefresh: _onRefresh,
        child: ListView.builder(
          itemCount: articleList.length,
          controller: _scrollController,
          itemBuilder:(BuildContext context,int index){
            return  Container(
              margin:EdgeInsets.all(10.0),
              decoration: BoxDecoration(
                  color: Colors.white70,
                  border: Border.all(color: Colors.white, width: 1.0),
                  borderRadius: BorderRadius.all(Radius.circular(12.0))
              ),
              child:
              GestureDetector(
                onTap: (){
                  Map<String, String> map = {"url": articleList[index].link};
                   myPlugin.invokeMethod("setWebViewUrl",map);//把url传递给原生页面
                },
                child:ConstrainedBox(//需要包上一层，否则会报错
                  constraints: BoxConstraints.tightForFinite(width: double.infinity,height: 120.0),
                  child: Stack(
                    alignment:Alignment.center , //指定未定位或部分定位widget的对齐方式
                    children: <Widget>[
                      Positioned(
                        top: 8.0,
                        left: 8.0,
                        child: Text(articleList[index].shareUser==""?articleList[index].author:articleList[index].shareUser),
                      ),
                      Positioned(
                        right: 8.0,
                        top: 8.0,
                        child: Text(articleList[index].niceShareDate),
                      ),
                      Container(
                        padding: EdgeInsets.only(left: 8.0,top: 35.0,right: 8.0),
                        child:
                        Column(
                          children: <Widget>[
                            Expanded(//Expanded只能在Row Colum中，否则会有异常。如果不加ExpandedText无法实现自动换行
                              child:
                              Align(//如果不包一层Align，会出现文字换行第二行居中
                                alignment: Alignment.topLeft,
                                child:
                                Text(articleList[index].title,
                                  overflow: TextOverflow.ellipsis,
                                  maxLines: 2,
                                  style: TextStyle(
                                    color: Colors.black,
                                    fontWeight: FontWeight.bold,
                                    fontSize: 15.0,
                                  ),
                                ),
                              ) ,
                            ),
                          ],
                        ),
                      ),
                      Positioned(
                        left: 8.0,
                        bottom: 16.0,
                        child: Text(articleList[index].superChapterName,style: TextStyle(
                            color: Colors.red
                        ),),
                      ),
                      Positioned(
                        right: 8.0,
                        bottom: 16.0,
                        child: Image(
                          width: 15.0,
                          height: 15.0,
                          image: AssetImage("assets/images/love.png"),
                        ),
                      ),
                    ],
                  ),
                ) ,
              ),
            );
          },
        ),
      ),
    );
  }

}

网络请求的类可以去上一篇文章找，中间遇见的问题Text无法自动换行，加上Expand包一层就好，又遇见第二个问题，换行之后第二行居中，加了一层Align就好了。中间有Flutter把webUrl传递给原生，原生的代码如下：

package com.example.flutter_weight_ui

import android.content.Intent
import android.os.Bundle
import io.flutter.app.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugins.GeneratedPluginRegistrant

class MainActivity: FlutterActivity() {
    private val CHANNEL = "samples.flutter.io/webview"//通道名称
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        GeneratedPluginRegistrant.registerWith(FlutterEngine(this))
        MethodChannel(flutterView, CHANNEL).setMethodCallHandler { call, result ->
            if(call.method=="setWebViewUrl"){//flutter方法名称
                var url:String = call.argument("url")!!
                var intent = Intent(this,WebViewActivity::class.java).putExtra("url", url)
                startActivity(intent)
            }
        }
    }
}

package com.example.flutter_weight_ui

import android.app.Activity
import android.os.Bundle
import android.webkit.WebView

class WebViewActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_webview)
         var webview:WebView = findViewById(R.id.webview);
        webview.loadUrl(intent.getStringExtra("url"))
    }
}

在清单文件中注册一下