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[操作系统][android] 练习使用ListView(一)


练习使用ListView,BaseAdapter,先展示文字的,再练习图片的

MainActivity.java

package com.android.test;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ListAdapter;import android.widget.ListView;import android.widget.TextView;public class MainActivity extends Activity {  private ListView lv_images;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    lv_images = (ListView) findViewById(R.id.lv_images);    ListAdapter adapter = new ImageAdapter();    lv_images.setAdapter(adapter);  }  /**   * 适配器   * @author taoshihan   *   */  class ImageAdapter extends BaseAdapter {    @Override    public View getView(int position, View convertView, ViewGroup parent) {      String url=(String) getItem(position);      View view;      if(convertView!=null){        view=convertView;      }else{        view=View.inflate(getApplicationContext(), R.layout.image_item, null);      }      TextView tv_image=(TextView) view.findViewById(R.id.tv_image);            tv_image.setText(url);      return view;    }    @Override    public int getCount() {      // TODO Auto-generated method stub      return Images.IMAGE_URLS.length;    }    @Override    public Object getItem(int position) {      return Images.IMAGE_URLS[position];    }    @Override    public long getItemId(int position) {      // TODO Auto-generated method stub      return position;    }  }  static class Images{    public final static String[] IMAGE_URLS = new String[]{      "http://img.my.csdn.net/uploads/201508/05/1438760758_3497.jpg",        "http://img.my.csdn.net/uploads/201508/05/1438760758_6667.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760757_3588.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760756_3304.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760755_6715.jpeg",       "http://img.my.csdn.net/uploads/201508/05/1438760726_5120.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760726_8364.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760725_4031.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760724_9463.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760724_2371.jpg",       "http://img.my.csdn.net/uploads/201508/05/1438760707_4653.jpg"    };  }}

activity_main.

<??><LinearLayout ="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:orientation="vertical">  <ListView     android:layout_width="match_parent"    android:layout_height="wrap_content"    android:id="@+id/lv_images"></ListView></LinearLayout>

image_item.

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