Android开发 ListView的用法

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首先说一下在其中遇到的的一个巨大的Bug.

由于没有在意ListView的id的设置导致程序出错。
对初学者来说我的理解是：ListView不像其他控件那样必须进行findviewbyid操作，因为ListView有默认的id那就是android：list

详见下面的代码

xml1

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:orientation="vertical"    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="com.example.genius.listview.MainActivity"><LinearLayout    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"><ListView    android:id="@+id/android:list"    <!--就是这里对id 的设置-->    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:scrollbars="vertical"    android:drawSelectorOnTop="false">    <!--scrollobars是ListView的数量超过屏幕大小后的填充方式--></ListView></LinearLayout></LinearLayout>

xml2

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"><TextView    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:id="@+id/username"    android:layout_gravity="left"/><TextView    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:id="@+id/phone"    android:layout_gravity="right"/></LinearLayout>

MainActivity

package com.example.genius.listview;import android.app.ListActivity;import android.os.Bundle;import android.view.View;import android.widget.ListView;import android.widget.SimpleAdapter;import java.util.ArrayList;import java.util.HashMap;public class MainActivity extends ListActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    ArrayList<HashMap<String, String>> list = new ArrayList<>();    HashMap<String, String> map1 = new HashMap<>();    HashMap<String, String> map2 = new HashMap<>();    HashMap<String, String> map3 = new HashMap<>();    map1.put("username", "Tom");    map1.put("phone", "1105221");    map2.put("username", "kite");    map2.put("phone", "555451");    map3.put("username", "Pig");    map3.put("phone", "751521");    list.add(map1);    list.add(map2);    list.add(map3);    SimpleAdapter simpleAdapter = new SimpleAdapter(this, list, R.layout.user,            new String[]{"username", "phone"}, new int[]{R.id.username, R.id.phone});    setListAdapter(simpleAdapter);}   @Override   protected void onListItemClick(ListView l, View v, int position, long id) {   super.onListItemClick(l, v, position, id);   //you can do something you want to do here .    }}

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