Android控件之ListView探究一

在android开发中ListView是比较常用的组件，它以列表的形式展示具体内容，并且能够根据数据的长度自适应显示。

main.xml布局文件

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

list_items.xml布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical" android:layout_width="fill_parent"
	android:layout_height="wrap_content" android:id="@+id/myListItem"
	android:paddingBottom="4dip" android:paddingLeft="12dip"
	android:paddingRight="12dip">
	<TextView android:layout_height="wrap_content"
		android:layout_width="fill_parent" android:id="@+id/itemTitle"
		android:textSize="20dip" android:layout_weight="1">
	</TextView>
	<TextView android:layout_height="wrap_content"
		android:layout_width="fill_parent" android:id="@+id/itemText">
	</TextView>
</LinearLayout>

MyList.java类文件

package iaiai.test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnCreateContextMenuListener;
import android.widget.AdapterView;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

public class MyList extends Activity {

	private ListView list;

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

		list = (ListView) findViewById(R.id.MyListView);

		// 配置适配器
		SimpleAdapter adapter = new SimpleAdapter(this, getData(),// 数据源
				R.layout.list_items,// 显示布局
				new String[] { "itemTitle", "itemText" }, // 数据源的属性字段
				new int[] { R.id.itemTitle, R.id.itemText }); // 布局里的控件id
		// 添加并且显示
		list.setAdapter(adapter);

		// 添加点击
		list.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
					long arg3) {
				setTitle("点击第" + arg2 + "个项目");
				Toast.makeText(MyList.this, "点击第" + arg2 + "个项目",
						Toast.LENGTH_LONG).show();
			}
		});

		// 添加长按点击
		list.setOnCreateContextMenuListener(new OnCreateContextMenuListener() {
			@Override
			public void onCreateContextMenu(ContextMenu menu, View v,
					ContextMenuInfo menuInfo) {
				// menu.setHeaderIcon(R.drawable.icon); //字义图片样式
				menu.setHeaderTitle("长按菜单选项:");
				menu.add(1, 0, 0, "编辑");
				menu.add(0, 1, 0, "删除");
			}
		});
	}

	@Override
	public boolean onContextItemSelected(MenuItem item) {
		int selectedPosition = ((AdapterContextMenuInfo) item.getMenuInfo()).position; // 刚才选择的
		Map<String, String> map = (HashMap) list
				.getItemAtPosition(selectedPosition); // ListView中的数据
		Toast.makeText(MyList.this,
				"你选择的:" + selectedPosition + "，内容为:" + map.get("itemTitle"),
				Toast.LENGTH_LONG).show(); // 显示那条数据

		String temp = "";
		switch (item.getItemId()) {
		case 0:
			temp = "编辑";
			break;
		case 1:
			temp = "删除";
			break;
		default:
			break;
		}
		// Toast.makeText(this, temp + "處理", Toast.LENGTH_LONG).show();
		return super.onContextItemSelected(item);
	}

	private List<Map<String, String>> getData() {
		// 组织数据源
		List<Map<String, String>> mylist = new ArrayList<Map<String, String>>();
		for (int i = 0; i < 10; i++) {
			Map<String, String> map = new HashMap<String, String>();
			map.put("itemTitle", "文章" + i);
			map.put("itemText", "Android 小项目" + i);
			mylist.add(map);
		}
		return mylist;
	}

	/**
	 * listview中点击按键弹出对话框
	 */
	public void showInfo() {
		new AlertDialog.Builder(this).setTitle("我的listview")
				.setMessage("介绍...")
				.setPositiveButton("确定", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
					}
				}).show();
	}

}

运行结果:




ListView不可放入ScrollView中，否则UI效果不可预测。切记切记