Android中BaseAdapter用法示例

本文实例讲述了Android中BaseAdapter用法。分享给大家供大家参考,具体如下:

概述:

BaseAdapter就Android应用程序中经常用到的基础数据适配器,它的主要用途是将一组数据传到像ListView、Spinner、Gallery及GridView等UI显示组件,它是继承自接口类Adapter

BaseAdapter

Java代码:

public class RecentAdapter extends BaseAdapter {  private class RecentViewHolder {    TextView appName;    ImageView appIcon;    TextView appSize;  }  private List<ResolveInfo> mAppList;  private LayoutInflater mInflater;  private PackageManager pm;  public RecentAdapter(Context c, List<ResolveInfo> appList,      PackageManager pm) {    mAppList = appList;    this.pm = pm;    mInflater = (LayoutInflater) c        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);  }  public void clear(){    if(mAppList!=null){      mAppList.clear();    }  }  public int getCount() {    return mAppList.size();  }  @Override  public Object getItem(int position) {    return mAppList.get(position);  }  @Override  public long getItemId(int position) {    // TODO Auto-generated method stub    return position;  }  public View getView(int position, View convertView, ViewGroup parent) {    RecentViewHolder holder;    if (convertView == null) {      convertView = mInflater.inflate(R.layout.app_info_item, null);      holder = new RecentViewHolder();      holder.appName = (TextView) convertView.findViewById(R.id.app_name);      holder.appIcon = (ImageView) convertView          .findViewById(R.id.app_icon);      holder.appSize = (TextView) convertView.findViewById(R.id.app_size);      convertView.setTag(holder);    } else {      holder = (RecentViewHolder) convertView.getTag();    }    ResolveInfo appInfo = mAppList.get(position);    if (appInfo != null) {      String labelName = appInfo.loadLabel(pm).toString();      if (labelName != null) {        holder.appName.setText(labelName);      }      Drawable icon = appInfo.loadIcon(pm);      if (icon != null) {        holder.appIcon.setImageDrawable(icon);      }    }    return convertView;  }  public void remove(int position){    mAppList.remove(position);    this.notifyDataSetChanged();  }}

其中两个注意点为:

setTag 用View设置存储数据

notifyDataSetChanged() 告诉View数据更改并刷新

View convertView = mInflater.inflate(R.layout.app_info_item, null) 加载XML Item 视图

app_info_item.xml文件示例:

xml代码:

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent" android:layout_height="wrap_content"  android:layout_gravity="center_vertical" android:minHeight="?android:attr/listPreferredItemHeight">  <ImageView android:id="@+id/app_icon" android:layout_width="@android:dimen/app_icon_size"    android:layout_height="@android:dimen/app_icon_size"    android:layout_alignParentLeft="true" android:paddingLeft="6dip"    android:paddingTop="6dip" android:paddingBottom="6dip"    android:scaleType="fitCenter" />  <TextView android:id="@+id/app_name" android:layout_width="wrap_content"    android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge"    android:textColor="?android:attr/textColorPrimary"    android:layout_toRightOf="@id/app_icon" android:paddingLeft="6dip"    android:paddingTop="6dip" />  <TextView android:id="@+id/app_description"    android:layout_width="wrap_content" android:layout_height="wrap_content"    android:textAppearance="?android:attr/textAppearanceSmall"    android:layout_below="@+id/app_name" android:layout_toRightOf="@id/app_icon"    android:paddingLeft="6dip" android:paddingBottom="6dip" />  <TextView android:id="@+id/app_size" android:layout_width="wrap_content"    android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceSmall"    android:layout_alignParentRight="true" android:layout_below="@+id/app_name"    android:paddingRight="6dip" android:maxLines="1" /></RelativeLayout>

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希望本文所述对大家Android程序设计有所帮助。

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Android中BaseAdapter用法示例

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