android之ListView模拟新闻显示

一、项目目录结构

二、layout界面

三、layout界面xml代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.zgs.listview_news.MainActivity" >    <ListView        android:id="@+id/lv_news"        android:layout_width="fill_parent"        android:layout_height="fill_parent" /></RelativeLayout>

四、NewsBean类代码

package com.zgs.listview_news_bean;import android.graphics.drawable.Drawable;public class NewsBean {public String title;public String des;public Drawable icon; public String news_url;}

五、NewsUtils类代码

package com.zgs.listview_news.utils;import java.util.ArrayList;import android.content.Context;import android.support.v4.content.ContextCompat;import com.zgs.listview_news.R;import com.zgs.listview_news_bean.NewsBean;public class NewsUtils {//封装新闻的假数据到list中返回,以后数据会从数据库中获取public static ArrayList<NewsBean> getAllNews(Context context) {ArrayList<NewsBean> arrayList = new ArrayList<NewsBean>();for(int i = 0 ;i <100;i++){NewsBean newsBean = new NewsBean();newsBean.title ="火箭发射成功";newsBean.des= "搜索算法似懂非懂三分得手房贷首付第三方的手";newsBean.news_url= "http://www.sina.cn";newsBean.icon = ContextCompat.getDrawable(context, R.drawable.adb);; //通过context对象将一个资源id转换成一个Drawable对象。arrayList.add(newsBean);NewsBean newsBean1 = new NewsBean();newsBean1.title ="似懂非懂瑟瑟发抖速度";newsBean1.des= "地方上的房贷首付读书首付第三方的手房贷首付第三方的手负担";newsBean1.news_url= "http://www.baidu.cn";newsBean1.icon = ContextCompat.getDrawable(context, R.drawable.shopping);;//通过context对象将一个资源id转换成一个Drawable对象。arrayList.add(newsBean1);NewsBean newsBean2 = new NewsBean();newsBean2.title ="豆腐皮人热舞";newsBean2.des= "费解的是离开房间打扫李开复离开独守空房迪斯科浪费电锋克劳利分级恐龙快打";newsBean2.news_url= "http://www.qq.com";newsBean2.icon = ContextCompat.getDrawable(context, R.drawable.tutorial);;//通过context对象将一个资源id转换成一个Drawable对象。arrayList.add(newsBean2);}return arrayList;}}

六、item_news_layout.xml代码

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingTop="20dp"    android:paddingBottom="20dp"    android:orientation="horizontal" >    <ImageView        android:layout_gravity="center"        android:id="@+id/item_img_icon"        android:layout_width="68dp"        android:layout_height="68dp"        android:layout_marginRight="10dp"        android:src="@drawable/ic_launcher" />    <LinearLayout          android:layout_gravity="center"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="vertical" >        <TextView            android:singleLine="true"            android:id="@+id/item_tv_title"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:layout_marginBottom="3dp"            android:text="title"            android:textColor="#000000"            android:textSize="16sp" />        <TextView            android:maxLines="2"            android:id="@+id/item_tv_des"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:text="des"            android:textColor="#666666"            android:textSize="13sp" />    </LinearLayout></LinearLayout>

七、NewsAdapter类代码

package com.zgs.listview_news_adapter;import java.util.ArrayList;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import com.zgs.listview_news.R;import com.zgs.listview_news_bean.NewsBean;public class NewsAdapter extends BaseAdapter{private ArrayList<NewsBean> list;private Context context;//通过构造方法接受要显示的新闻数据集合public NewsAdapter(Context context, ArrayList<NewsBean> list) {this.list = list;this.context = context;}@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int position) {return list.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {View view = null;//1.复用converView优化listview,创建一个view作为getview的返回值用来显示一个条目if(convertView != null){view = convertView;}else {//方法一：推荐//context:上下文, resource:要转换成view对象的layout的id, root:将layout用root(ViewGroup)包一层作为codify的返回值,一般传nullview = View.inflate(context, R.layout.item_news_layout, null);//将一个布局文件转换成一个view对象//方法二//通过LayoutInflater将布局转换成view对象//view =  LayoutInflater.from(context).inflate(R.layout.item_news_layout, null);//方法三：系统级开发//通过context获取系统服务得到一个LayoutInflater，通过LayoutInflater将一个布局转换为view对象//LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);//view = layoutInflater.inflate(R.layout.item_news_layout, null);}//2.获取view上的子控件对象ImageView item_img_icon = (ImageView) view.findViewById(R.id.item_img_icon);TextView item_tv_des = (TextView) view.findViewById(R.id.item_tv_des);TextView item_tv_title = (TextView) view.findViewById(R.id.item_tv_title);//3.获取postion位置条目对应的list集合中的新闻数据，Bean对象NewsBean newsBean = list.get(position);//4.将数据设置给这些子控件做显示item_img_icon.setImageDrawable(newsBean.icon);//设置imageView的图片item_tv_title.setText(newsBean.title);item_tv_des.setText(newsBean.des);return view;}}

八、MainActivity类代码

package com.zgs.listview_news;import java.util.ArrayList;import com.zgs.listview_news.utils.NewsUtils;import com.zgs.listview_news_adapter.NewsAdapter;import com.zgs.listview_news_bean.NewsBean;import android.app.Activity;import android.content.Context;import android.content.Intent;import android.net.Uri;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.ListView;public class MainActivity extends Activity implements OnItemClickListener {private Context mContext;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mContext = this;//养成先写思路，再写程序的习惯//1：用模拟新闻假数据，用list封装//2：布局ListView//3：获取ListView控件//4：创建一个adapter设置给listview//5：设置ListView条目单击事件//1.获取新闻数据用list封装ArrayList<NewsBean> allNews = NewsUtils.getAllNews(mContext);//2.找到控件ListView lv_news = (ListView) findViewById(R.id.lv_news);//3.创建一个adapter设置给listviewNewsAdapter newsAdapter = new NewsAdapter(mContext, allNews);lv_news.setAdapter(newsAdapter);//4.设置listview条目的点击事件lv_news.setOnItemClickListener(this);}//listview的条目点击时会调用该方法   parent:代表listviw  view:点击的条目上的那个view对象   position:条目的位置  id： 条目的id@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position,long id) {//需要获取条目上bean对象中url做跳转NewsBean bean = (NewsBean) parent.getItemAtPosition(position);String url = bean.news_url;//跳转浏览器Intent intent = new Intent();intent.setAction(Intent.ACTION_VIEW);intent.setData(Uri.parse(url));startActivity(intent);}}

九、运行效果