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:

[img]http://dl.iteye.com/upload/attachment/489582/d468cf2b-5327-3d58-bb15-ec53845fd33d.jpg[/img]

[img]http://dl.iteye.com/upload/attachment/489977/6f7682b7-24ec-3908-a813-6c5056227a01.jpg[/img]

[img]http://dl.iteye.com/upload/attachment/489979/f9a730ae-ad0a-3ec6-aee2-55222e116f2e.jpg[/img]

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