android_20_ListView_BaseAdapter

效果:

清单文件:

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.sg31.listviewwithbaseadapter"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="21" />    // 测试用的,注意包名和节点位置    <instrumentation android:name="android.test.InstrumentationTestRunner"    android:targetPackage="com.sg31.listviewwithbaseadapter"></instrumentation>        <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <uses-library android:name="android.test.runner"/>        <activity            android:name=".MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

 

布局文件:

<LinearLayout 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="com.sg31.listviewwithbaseadapter.MainActivity" >    <ListView         android:id="@+id/listView"        android:layout_width="match_parent"        android:layout_height="match_parent"        ></ListView></LinearLayout>

自定义cell:

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >        <TextView     android:id="@+id/tv_name"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="名字"    android:textSize="25sp"    /><LinearLayout     android:layout_alignParentRight="true"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:orientation="vertical"    >    <TextView         android:id="@+id/tv_pwd"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="密码"    />    <TextView         android:id="@+id/tv_phone"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="手机"    /></LinearLayout></RelativeLayout>

模型类:

package com.sg31.listviewwithbaseadapter;public class User {public String _id;public String name;public String pwd;public String phone;public User(String _id2, String name2, String pwd2, String phone2) {this._id = _id2;this.name = name2;this.pwd = pwd2;this.phone = phone2;}public String get_id() {return _id;}public void set_id(String _id) {this._id = _id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPwd() {return pwd;}public void setPwd(String pwd) {this.pwd = pwd;}public String getPhone() {return phone;}public void setPhone(String phone) {this.phone = phone;}@Overridepublic String toString() {return this._id + ";" + this.name + ";" + this.pwd + ";" + this.phone;}}

数据库帮助类:

package com.sg31.listviewwithbaseadapter;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.database.sqlite.SQLiteDatabase.CursorFactory;public class SGDBHelper extends SQLiteOpenHelper {public SGDBHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);}@Overridepublic void onCreate(SQLiteDatabase db) {// 数据库创建时,建表System.out.println("数据库创建时调用");db.execSQL("create table user(_id integer primary key autoincrement, name char(10), pwd char(10), phone integer(20))");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {System.out.println("数据库升级时调用");}}

单元测试类:

package com.sg31.listviewwithbaseadapter;import android.content.ContentValues;import android.database.sqlite.SQLiteDatabase;import android.test.AndroidTestCase;public class SQLDatabaseTest extends AndroidTestCase {private SGDBHelper dbHelper;private SQLiteDatabase db;@Overrideprotected void setUp() throws Exception {super.setUp();// 初始化// 建立数据库引用dbHelper = new SGDBHelper(getContext(), "user.sqlite", null, 1);db = dbHelper.getWritableDatabase();System.out.println("sg__"+db.toString());}@Overrideprotected void tearDown() throws Exception {super.tearDown();// 收尾工作db.close();}// 使用封装好的API进行CRUDpublic void testInsertApi(){System.out.println("testInsertApi");for (int i = 0; i < 100; i++) {//把要插入的数据全部封装至ContentValues对象ContentValues values = new ContentValues();values.put("name", "shuiying"+i);values.put("pwd", "sg31.com");values.put("phone", 1346943+i);long _id = db.insert("user", null, values);System.out.println("sg__"+_id);}                            }}

控制器:

package com.sg31.listviewwithbaseadapter;import java.util.ArrayList;import java.util.List;import android.support.v7.app.ActionBarActivity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.TextView;public class MainActivity extends ActionBarActivity {List<User> userList;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                loadDataFromDB();    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);        return true;    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int id = item.getItemId();        if (id == R.id.action_settings) {            return true;        }        return super.onOptionsItemSelected(item);    }        // 从数据库中查询,并显示到界面    private void loadDataFromDB() {    userList = new ArrayList<User>();        //把数据库的数据查询出来        SGDBHelper oh = new SGDBHelper(this, "user.sqlite", null, 1);        SQLiteDatabase db =  oh.getWritableDatabase();        Cursor cursor = db.query("User", null, null, null, null, null, null, null);        while(cursor.moveToNext()){            String _id = cursor.getString(cursor.getColumnIndex("_id"));            String name = cursor.getString(cursor.getColumnIndex("name"));            String pwd = cursor.getString(cursor.getColumnIndex("pwd"));            String phone = cursor.getString(cursor.getColumnIndex("phone"));                                                User p = new User(_id, name,pwd, phone);            userList.add(p);        }                // 使用ListView进行展示        ListView listView = (ListView) findViewById(R.id.listView);        listView.setAdapter(new SGBaseAdapter());            }        class SGBaseAdapter extends BaseAdapter{                //系统调用，用来获知集合中有多少条元素        @Override        public int getCount() {            return userList.size();        }                //由系统调用，获取一个View对象，作为ListView的条目        //position:本次getView方法调用所返回的View对象，在listView中是处于第几个条目，那么position的值就是多少        @Override        public View getView(int position, View convertView, ViewGroup parent) {            User p = userList.get(position);                        // 先从缓存池中取,取不到,new一个            View v = convertView;            CellViewHolder cellViewHolder = null;            if (v != null) {            cellViewHolder = (CellViewHolder)v.getTag();}                                    //判断条目是否有缓存            if(v == null){                //把布局文件填充成一个View对象                v = View.inflate(MainActivity.this, R.layout.list_cell, null);                                // cell内部的控件也要缓存,通过资源id查找组件,注意调用的是View对象的findViewById                cellViewHolder = new CellViewHolder();                cellViewHolder.tv_Name = (TextView)v.findViewById(R.id.tv_name);                cellViewHolder.tv_Pwd = (TextView)v.findViewById(R.id.tv_pwd);                cellViewHolder.tv_Phone = (TextView)v.findViewById(R.id.tv_phone);                // tip,通过tag绑定                v.setTag(cellViewHolder);            }                        cellViewHolder.tv_Name.setText(p.getName());            cellViewHolder.tv_Pwd.setText(p.getPwd());            cellViewHolder.tv_Phone.setText(p.getPhone());            return v;        }                @Override        public Object getItem(int position) {            return null;        }                @Override        public long getItemId(int position) {            return 0;        }            }        // 静态内部类,免去每次查找的烦恼,提升5%性能    private static class CellViewHolder {private TextView tv_Name;private TextView tv_Pwd;private TextView tv_Phone;}    }