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。