ListView总结之Adapter

1 概述

         绑定ListView数据的适配器有：ArrayAdapter、BaseAdapter、CursorAdapter、SimpleAdapter、ResourceCursorAdapter、SimpleCursorAdapter。在实际应用中，得根据实际情况选择合适的适配器。

一般来说，ArrayAdapter、BaseAdapter、SimpleAdapter、CursorAdapter是比较常用的，区别在于数据源的表现形式不同：

SimpleAdapter和BaseAdapter的数据源一般是List<String>或List<Map<String,?>>;

ArrayAdapter的数据源一般是String[];

CursorAdapter一般就是SQLite数据库了。

 

2 创建ListView布局文件ListView.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#F0F0F0"
    android:orientation="vertical" >

    <ListView
        android:id="@+id/listView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" 
        android:divider="#0072E3"    
        android:dividerHeight="0.5px">
    </ListView>

</LinearLayout>

 

3 创建listView中Item的布局文件Item.xml

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/honeycomb" />

    <LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">
    
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:paddingBottom="10dp"
        android:paddingTop="10dp"
        android:textSize="20sp" 
        android:text="title"/>

    <TextView
        android:id="@+id/content"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:paddingBottom="10dp"
        android:paddingTop="10dp"
        android:textSize="20sp" 
        android:text="content"/>
</LinearLayout>
</LinearLayout>

 

4 创建页脚布局，可以是加载按钮、加载进度条、“上一页”“下一页”之类的布局，看自己需求而定，如下是load_more.xml

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:orientation="vertical" >

        <ProgressBar
        android:id="@+id/load"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
        </ProgressBar>

</LinearLayout>

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:orientation="vertical" >

    <Button
        android:id="@+id/loadMoreButton"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:onClick="loadMore"
        android:text="加载更多" />

</LinearLayout>

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:orientation="vertical" >

        <Button
            android:id="@+id/btnPrevious"
            android:layout_width="160dip"
            android:layout_height="wrap_content"
            android:text="上一页" />

        <Button
            android:id="@+id/btnNext"
            android:layout_width="160dip"
            android:layout_height="wrap_content"
            android:text="下一页" />
</LinearLayout>

 

5 定义自己的数据源Adapter

 

根据自己的需求继承相应的Adapter

必须覆盖的方法：

getCount()

getItem(int position)

getItemId(int position)

getView(int position, ViewcontentView, ViewGroup arg2)

 

在getView中会根据数据源来渲染界面。下面是其中一个例子：

 

import java.util.List;
import java.util.Map;

import com.aaron.util.R;

import android.content.Context;
import android.text.Html;
import android.text.Spanned;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

/**
 * @author aaron
 * 
 */
public class TextSearchAdapter extends BaseAdapter {

	private LayoutInflater inflater;
	private String keyword;
	private PageModel mModel;
	private Context mContext;
	List<Map<String, Object>> ItemInfoList;

	public TextSearchAdapter(Context context,
			List<Map<String, Object>> ItemInfoList, PageModel pageModel,
			String keyword) {

		this.ItemInfoList = ItemInfoList;
		this.mContext = context;
		this.mModel = pageModel;
		this.keyword = keyword;
		inflater = (LayoutInflater) context
				.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

	}

	static class ViewHolder {
		TextView name;
		TextView department;
		TextView content;
	}

	/**
	 * [突出显示]
	 * 
	 * @param key
	 * @param s
	 * @param color
	 * @return
	 */
	private Spanned setKeyColor(String key, String s, String color) {
		String colorKey = "<font color=\"" + color + "\">" + key + "</font>";
		return Html.fromHtml(s.replace(key, colorKey));

	}

	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return ItemInfoList.size();
	}

	@Override
	public Object getItem(int position) {
		// TODO Auto-generated method stub
		return ItemInfoList.get(position);
	}

	@Override
	public long getItemId(int position) {
		// TODO Auto-generated method stub
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		// TODO Auto-generated method stub
		ViewHolder holder = null;

		if (holder == null) {
			convertView = inflater.inflate(R.layout.listview_item_sql, null);
			holder = new ViewHolder();

			holder.name = (TextView) convertView
					.findViewById(R.id.list_item_name);
			holder.department = (TextView) convertView
					.findViewById(R.id.list_item_department);
			holder.content = (TextView) convertView
					.findViewById(R.id.list_item_content);
			convertView.setTag(holder);
		} else {
			holder = (ViewHolder) convertView.getTag();
		}
		String item = (String) ItemInfoList.get(position).get("content");
		holder.content.setText(setKeyColor(keyword, item, "red"));
		holder.name.setText((CharSequence) ItemInfoList.get(position).get(
				"name"));
		holder.department.setText((CharSequence) ItemInfoList.get(position)
				.get("department"));
		return convertView;
	}

}

 

6 Activity中初始化

 

6.1 定义布局

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

 

6.2 添加页脚

listView.addFooterView(loadMoreView); 

 

当然根据需求也可以设置页头的：

listView.addHeaderView(loadHeadView);

 

6.3 绑定适配器

adapter = new TextSearchAdapter(this,ItemInfoList,mModel,keyWord);
        listView.setAdapter(adapter);

 

6.4 实现OnScrollListener接口，覆盖的方法：

onScroll(AbsListView view,int firstVisibleItem,

           int visibleItemCount,int totalItemCount)

onScrollStateChanged(AbsListViewview, int scrollState)

 

onscroll方法中对数据源进行逻辑处理。

数据更新：adapter.notifyDataSetChanged();

如果是绑定的是CursorAdapter，则adapter.changeCursor(mCursor);

adapter.notifyDataSetChanged();

 

6.5 实现OnItemClickListener接口，覆盖的方法

onItemClick(AdapterView<?> parent,View view,int position,

              long id)，实现Item点击事件

 

7 效果截图

 

分页的：