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[操作系统]我的android学习经历34


用类对象作为ArrayAdapter绑定的基本数据类型(和SimpleAdater效果类似)

一般ArrayAdapter绑定的基本数据类型是String,接下来介绍一下类对象作为基本数据类型;

首先,新建一个类News,这个类作为基本的数据类型

package com.example.news;import android.R.integer;import android.widget.ImageView;public class News {    private String title;    private String content;    private int imageId;       News(String title,String content,int imageId){      this.title=title;      this.content=content;      this.imageId=imageId;    }       public String getTitle() {    return title;  }    public String getContent() {      return content;    }    public int getimageId() {       return imageId;     }   public void setTitle(String title){     this.title=title;   }   public void setContent(String content){     this.content=content;   }}

接下来先把listView的item的布局确定下来,有一个Textview和ImageView;

<LinearLayout ="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:orientation="vertical" >  <TextView     android:id="@+id/news_title"    android:layout_width="wrap_content"    android:layout_height="wrap_content"/>  <ImageView     android:id="@+id/news_image"    android:layout_width="wrap_content"    android:layout_height="wrap_content"/></LinearLayout>

 

然后自定义一个适配器NewsAdapter,继承ArrayAdapter,并且实现其中的两个方法,resourceId也就是上面的listView的item的布局的id;

package com.example.news;import java.util.List;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ImageView;import android.widget.TextView;public class NewsAdapter extends ArrayAdapter<News>{    private int resourceId;    public NewsAdapter(Context context, int resource, List<News> objects) {    super(context, resource, objects);    // TODO Auto-generated constructor stub    resourceId=resource;  }  @Override  public View getView(int position, View convertView, ViewGroup parent) {    // TODO Auto-generated method stub     News news=getItem(position);    View view ;    if(convertView==null){      view=LayoutInflater.from(getContext()).inflate(resourceId, null);    }else {      view=convertView;    }    TextView news_title=(TextView) view.findViewById(R.id.news_title);    ImageView news_image=(ImageView) view.findViewById(R.id.news_image);        news_title.setText(news.getTitle());    news_image.setImageResource(news.getimageId());    return view;  }}

然后在主布局中添加一个listview控件,这个简单,大家肯定都会

<RelativeLayout ="http://schemas.android.com/apk/res/android"  ="http://schemas.android.com/tools"  android:layout_width="match_parent"  android:layout_height="match_parent"  tools:context="${relativePackage}.${activityClass}" >  <ListView     android:id="@+id/list_title"    android:layout_width="wrap_content"    android:layout_height="match_parent"></ListView></RelativeLayout>

然后重写主activity

import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.widget.ListView;public class MainActivity extends Activity {    private ListView list_title;  private List<News> list= new ArrayList<News>();    private NewsAdapter adapter;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    list_title=(ListView) findViewById(R.id.list_title);    initList();      adapter=new NewsAdapter(this, R.layout.news_item,list);    list_title.setAdapter(adapter);  }  private void initList() {        News news1=new News("标题1", "1", R.drawable.ic_launcher);    list.add(news1);    News news2=new News("标题2", "2", R.drawable.ic_launcher);    list.add(news2);    News news3=new News("标题3", "3", R.drawable.ic_launcher);    list.add(news3);    News news4=new News("标题4", "4", R.drawable.ic_launcher);    list.add(news4);  }  }

界面效果

 

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