AdapterView及其子类之四：基于ListView及SimpleAdapter实现列表

时间：2021-03-07 16:51:08

代码请见SimpleAdapterDemo.zip。

步骤如下：

1、创建主布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <ListView

        android:id="@+id/listview"

        android:layout_height="wrap_content"

        android:layout_width="match_parent"

        android:divider="#00ff00"

        android:dividerHeight="2dp"

        android:headerDividersEnabled="false"

         />

</RelativeLayout>

2、创建每个列表选项的视图

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/ll_listview"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:orientation="horizontal" >

    <ImageView

        android:id="@+id/iv_header"

        android:layout_width="0dp"

        android:layout_height="40dp"

        android:layout_weight="1"

        android:contentDescription="@string/header"/>

    <LinearLayout

        android:id="@+id/ll_title_content"

        android:layout_width="0dp"

        android:layout_height="40dp"

        android:orientation="vertical"

        android:layout_weight="4">

        <TextView

            android:id="@+id/title"

            android:layout_width="match_parent"

            android:layout_height="20dp"

            android:background="#000000" />

        <TextView

            android:id="@+id/content"

            android:layout_width="match_parent"

            android:layout_height="20dp"

            android:background="#00ff00" />

    </LinearLayout>

</LinearLayout>

3、创建主类

package com.ljh.listviewdemo;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import android.os.Bundle;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.Toast;

import android.app.Activity;

public class MainActivity extends Activity {

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_main);

		// （1）创建要显示的文本内容

		String[] arr = { "header", "title", "content" };

		// （2）与使用ListActivity的最大区别:使用findViewById得到一个ListView

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

		// （3）创建ArrayAdapter，其中第二个参数resource：The resource ID for a layout file

		// containing a TextView to use when instantiating views.是要以一个layout作为

		// 参数，且此layout需要包含textview。

		/*

		 * ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,

		 * R.layout.list, arr);

		 */

		String[] titles = { "title1", "title2", "title3", "title4" };

		String[] contents = { "content1", "content2", "content3", "content4" };

		int[] headers = { R.drawable.p1, R.drawable.p2, R.drawable.p3,

				R.drawable.p4 };

		List<Map<String, Object>> datas = new ArrayList<Map<String, Object>>();

		/*

		 * Parameters:

		 * context The context where the View associated with this

		 * SimpleAdapter is running data A List of Maps. Each entry in the List

		 * corresponds to one row in the list. The Maps contain the data for

		 * each row, and should include all the entries specified in "from"

		 * resource Resource identifier of a view layout that defines the views

		 * for this list item. The layout file should include at least those

		 * named views defined in "to" from A list of column names that will be

		 * added to the Map associated with each item. to The views that should

		 * display column in the "from" parameter. These should all be

		 * TextViews. The first N views in this list are given the values of the

		 * first N columns in the from parameter.

		 */SimpleAdapter adapter = new SimpleAdapter(this, datas,

				R.layout.list, arr, new int[] { R.id.iv_header, R.id.title,

						R.id.content });

		for (int i = 0; i < titles.length; i++) {

			Map<String, Object> map = new HashMap<String, Object>();

			map.put("title", titles[i]);

			map.put("content", contents[i]);

			map.put("header", headers[i]);

			datas.add(map);

		}

		// （4）为ListActivity设置adapter.

		lv.setAdapter(adapter);

		lv.setOnItemClickListener(new OnItemClickListener() {

			// 定义当某个选项被点击时的操作。

			@Override

			public void onItemClick(AdapterView<?> parent, View view,

					int position, long id) {

				Toast.makeText(MainActivity.this,

						position + " item is clicked.", Toast.LENGTH_LONG)

						.show();

			}

		});

	}

}

AdapterView及其子类之四：基于ListView及SimpleAdapter实现列表

1、使用SimpleAdapter与ArrayAdapter相比，它可以支持复杂的表项结构，而不只是单一的textview。

2、其创建过程的两个主要区别是：

（1）每个列表项的布局文件不一样

（2）创建SimpleAdapter的操作更为复杂，需要构建一个List<Map<String, Object>>。

相关文章