Android复写BaseAdapter并显示ListView视图

最新推荐文章于 2021-06-30 10:34:39 发布

liuyiming_

最新推荐文章于 2021-06-30 10:34:39 发布

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文章标签： listview android string attributes iterator list

本文链接：https://blog.youkuaiyun.com/liuyiming_/article/details/7462118

本文通过一个具体实例展示了如何使用BaseAdapter实现ListView的多行显示效果。包括自定义适配器类、解析XML文件填充数据列表及在Activity中设置ListView等关键步骤。

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使用BaseAdaper时，我们常写一个类来继承它。因为BaseAdapter是一个抽象类，所以继承它必修实现它的方法。下面用一个小例子来学习BaseAdapter适配器实现ListView的多行显示效果。

例子的目录结构：

com.person.adapter包：

public class MyAdapter extends BaseAdapter {

	LayoutInflater mInflater;
	List<PersonInfo> list;

	public MyAdapter(Context context, List<PersonInfo> list) {
		super();
		this.mInflater = LayoutInflater.from(context);
		this.list = list;

	}

	// 内部类优化作用
	public final class ViewHolder {
		public TextView id;
		public TextView name;
		public TextView address;
		public ImageView img;

	}

	@Override
	public int getCount() {

		return list.size();
	}

	@Override
	public Object getItem(int position) {

		return null;
	}

	@Override
	public long getItemId(int position) {

		return 0;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		ViewHolder viewHolder = null;
		if (convertView == null) {
			viewHolder = new ViewHolder();
			convertView = mInflater.inflate(R.layout.list_item, null);
			viewHolder.id = (TextView) convertView.findViewById(R.id.tv_id);
			viewHolder.name = (TextView) convertView.findViewById(R.id.tv_name);
			viewHolder.address = (TextView) convertView
					.findViewById(R.id.tv_address);
			convertView.setTag(viewHolder);
		} else {
			viewHolder = (ViewHolder) convertView.getTag();
		}
		viewHolder.id.setText(list.get(position).getId());
		viewHolder.name.setText(list.get(position).getName());
		viewHolder.address.setText(list.get(position).getAddress());
		return convertView;
	}

}

com.person.activity包：

public class MianActivity extends Activity {

	private ListView listView;
	private MyAdapter adapter;
	List<PersonInfo> list = new ArrayList<PersonInfo>();

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		listView = (ListView) findViewById(R.id.lv);

		SAXParserFactory factory = SAXParserFactory.newInstance();
		try {

			XMLReader reader = factory.newSAXParser().getXMLReader();
			XMLParse xmlParse = new XMLParse(list);
			reader.setContentHandler(xmlParse);
			InputStream is = getResources().openRawResource(R.raw.person);
			reader.parse(new InputSource(is));
			// 测试
			for (Iterator iterator = list.iterator(); iterator.hasNext();) {
				PersonInfo personInfo = (PersonInfo) iterator.next();
				System.out.println(personInfo.getId());
				System.out.println(personInfo.getName());
				System.out.println(personInfo.getAddress());

			}

		} catch (Exception e) {
			e.printStackTrace();

		}

		adapter = new MyAdapter(this, list);
		listView.setAdapter(adapter);

	}
}

com.person.model包：

public class PersonInfo {
	
	private String  id;
	private String name;
	private String address;
	
	public PersonInfo(){
		super();
	}
	
	public void setId(String id){
		this.id = id;
	}
	public String getId(){
		return id;
	}
	
	public  void setName(String name){
		this.name = name;
	}
	public String getName(){
		return name;
	}
	
	public  void setAddress(String address){
		this.address = address;
	}
	public String getAddress(){
		return address;
	}

}

com.person.parse包：

public class XMLParse extends DefaultHandler {

	private String tag;
	List<PersonInfo> list;;
	PersonInfo personInfo;

	// 构造方法实例化list
	public XMLParse(List<PersonInfo> list) {
		super();
		this.list = list;
	}

	@Override
	public void startDocument() throws SAXException {
		super.startDocument();
	}

	@Override
	public void startElement(String uri, String localName, String qName,
			Attributes attributes) throws SAXException {
		if (localName.equals("person")) {
			personInfo = new PersonInfo();
		}

		tag = localName;
		super.startElement(uri, localName, qName, attributes);
	}

	@Override
	public void characters(char[] ch, int start, int length)
			throws SAXException {
		String str = new String(ch, start, length);

		if (tag.equals("id")) {
			personInfo.setId(str);

		} else if (tag.equals("name")) {
			personInfo.setName(str);

		} else if (tag.equals("address")) {
			personInfo.setAddress(str);

		}

		super.characters(ch, start, length);
	}

	@Override
	public void endElement(String uri, String localName, String qName)
			throws SAXException {
		// 此处是pName而不再是localName
		if (qName.equals("person")) {
			list.add(personInfo);
		}
		tag = "";

		super.endElement(uri, localName, qName);
	}

	@Override
	public void endDocument() throws SAXException {

		super.endDocument();
	}

}

效果图：