BaseAdapter

Person 类：

<span style="font-size:18px;">package com.xh.tx.bean;public class Person {private Integer _id;private String name;private Integer age;public Integer get_id() {return _id;}public void set_id(Integer _id) {this._id = _id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Person() {super();// TODO Auto-generated constructor stub}public Person(Integer _id, String name, Integer age) {super();this._id = _id;this.name = name;this.age = age;}@Overridepublic String toString() {return "Person [_id=" + _id + ", name=" + name + ", age=" + age + "]";}}</span>

<span style="font-size:18px;">MySQLLiteHelper：</span>

<span style="font-size:18px;">package com.xh.tx.utils;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;import android.util.Log;public class MySQLLiteHelper extends SQLiteOpenHelper{/** * 函数的作用:构造方法用来创建工具类 * param1: context 上下文环境 * param2: name 数据库的名称 * param3: factory 游标对象Cursor  * parma4: varsion 数据库的版本 数据库的版本不能从0开始 * @param context */public MySQLLiteHelper(Context context, String name, CursorFactory factory,int version) {super(context, "test.db", null, 2);}/** * 用来创建数据库 */@Overridepublic void onCreate(SQLiteDatabase db) {String sql = "create table person (_id integer primary key, name varchar(20), age integer);";db.execSQL(sql);// 真正执行数据的创建}//数据库版本更新//版本需要发生变化，否则不会执行@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {Log.d("============", oldVersion + "  : " + newVersion);if(oldVersion == 1){String sql = "alter table person add balance integer;";db.execSQL(sql);}}//每次打开数据库的时候调用@Overridepublic void onOpen(SQLiteDatabase db) {super.onOpen(db);}}</span>

<span style="font-size:18px;">PersonDao ：</span>

<span style="font-size:18px;">package com.xh.tx.dao;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.SQLException;import android.database.sqlite.SQLiteDatabase;import com.xh.tx.bean.Person;import com.xh.tx.utils.MySQLLiteHelper;public class PersonDao {private MySQLLiteHelper helper;public PersonDao(Context context) {helper = new MySQLLiteHelper(context, null, null, -1);}/** * 对数据库进行添加操作 * sql:insert into person(name,age) values('sz',20);\ *缺陷: *1. 传递参数很麻烦 *2. 不能有返回值 */public void savePerson(Person p){String sql = "insert into person(name,age) values(?,?);";SQLiteDatabase db = helper.getWritableDatabase();//db代表的是一个数据库的一个连接if(db.isOpen())//判断数据库是否打开{db.execSQL("delete from person;");//添加前删除表里面所有的数据List<Person> list = new ArrayList<Person>();for(int i=0; i < 30; i++){list.add(new Person(i,"zs" + i,i));}for(Person person : list){db.execSQL(sql, new Object[]{person.getName(),person.getAge()}); //向数据库里面去添加一行记录}db.close(); //记住一定要关闭数据库的连接}}/** * 删除一个对象 * sql:delete from person where _id = 1; */public void deletePerson(Integer id){String sql = "delete from person where _id = ?;";SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){db.execSQL(sql, new Integer[]{id});db.close();}}/** * 修改一个对象 * sql:update person set name ='cccc' where _id=1; */public void updatePerson(Person p){String sql = "update person set name =? where _id=?;";SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){db.execSQL(sql, new Object[]{p.getName(),p.get_id()});db.close();}}/** * 查询所有 */public List<Person> queryPerson(){String sql = "select _id,name,age from person;";SQLiteDatabase db = helper.getReadableDatabase();List<Person> list = null;if(db.isOpen()){Cursor cursor = db.rawQuery(sql, null); //查询//cursor.getCount() 查看执行sql以后返回的结果集的个数if(null != cursor && cursor.getCount() > 0){list = new ArrayList<Person>();while(cursor.moveToNext()){Integer id = cursor.getInt(0);String name = cursor.getString(1);Integer age = cursor.getInt(2);list.add(new Person(id,name,age));}cursor.close();db.close();}}return list;}//Transation 事物public void Transation(){String sql1 ="update person set balance = balance - 1000 where _id = 1";String sql2 ="update person set balance = balance + 1000 where _id = 2";SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){//开启一个事物db.beginTransaction();try {db.execSQL(sql1);int i = 10/0;<span style="white-space:pre"></span>db.execSQL(sql2);    db.setTransactionSuccessful(); // 代表代码运行到这一行的时候是符合业务需求的，设置为事物成功} </span>

<span style="font-size:18px;">                finally{db.endTransaction(); //事物的结束，如果没有设置成功，那么会回滚你所做的任何操作,如果设置了则提交}db.close();}}}</span>

<span style="font-size:18px;">MainActivity：</span>

<span style="font-size:18px;">package com.example.baseadapter;import java.util.List;import com.xh.tx.bean.Person;import com.xh.tx.dao.PersonDao;import android.app.Activity;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 Activity {List<Person> list = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);PersonDao dao = new PersonDao(this);dao.savePerson(null);list = dao.queryPerson();ListView listview = (ListView) findViewById(R.id.list_view);listview.setAdapter(new MyAdapter());}class MyAdapter extends BaseAdapter{@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}/** * 缓存的是被遮住的那一行 */@Overridepublic View getView(int position, View convertView, ViewGroup parent) {TextView textview = null;if(null != convertView){textview = (TextView) convertView;}else{textview = new TextView(MainActivity.this);}textview.setText(list.get(position).toString());return textview;}}}</span>

<span style="font-size:18px;"> PersonDao1 ：</span>

<span style="font-size:18px;">package com.xh.tx.dao;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import com.xh.tx.bean.Person;import com.xh.tx.utils.MySQLLiteHelper;public class PersonDao1 {private static final String TAG = "PersonDao1";private MySQLLiteHelper helper;public PersonDao1(Context context){helper = new MySQLLiteHelper(context, null, null, 1);}public void savePerson(Person p){SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){//nullColumnHack 如果数据库里面的name子都设计的时候不允许为空,但是你传递过来的参数是空// 如果不设置这个nullColumnHack参数那么就会报错// 如果你设置nullColumnHack这个参数的值为name那么不会报错ContentValues values = new ContentValues();values.put("name", p.getName());values.put("age", p.getAge());Long id = db.insert("person", null, values);Log.d(TAG, "================:" + id);db.close();}}public void deletePerson(Integer id){SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){//select * from person where id=? and name = ?;String whereClause = "_id=?";String[] whereArgs = new String[]{String.valueOf(id)};int _id = db.delete("person", whereClause, whereArgs);Log.d(TAG, "================:" + _id);db.close();}}public void updatePerson(Person p){SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){ContentValues values = new ContentValues();values.put("name", "xintx");values.put("age", "2");String whereClause = "_id=?";String[] whereArgs = new String[]{String.valueOf(p.get_id())};db.update("peson", values, whereClause, whereArgs);db.close();}}public void queryItem(Integer id){SQLiteDatabase db = helper.getWritableDatabase();if(db.isOpen()){String[] columns = new String[]{"_id","name","age"};String selection = "_id=?";String[] selectionArgs = new String[]{String.valueOf(id)};String groupBy = null; //按什么什么分组String having = null; //如果select里面包含了组函数的时候，不能用where去查询 就只有用havingString orderBy = null; //按什么排序 order by id desc; Cursor cursor = db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);   if(null != cursor && cursor.moveToFirst()) { Integer _id = cursor.getInt(0); String name = cursor.getString(1); Integer age = cursor.getInt(2);  Log.d(TAG, "_id=" + _id + "  name=" + name + "  age = " + age);  db.close(); }}}}</span>

<span style="font-size:18px;"> MainActivity1 ：</span>

<span style="font-size:18px;">package com.example.baseadapter;import java.util.List;import com.xh.tx.bean.Person;import com.xh.tx.dao.PersonDao;import android.app.Activity;import android.os.Bundle;import android.view.LayoutInflater;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 MainActivity1 extends Activity {List<Person> list = null;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);PersonDao dao = new PersonDao(this);//dao.savePerson(null);list = dao.queryPerson();ListView listview = (ListView) findViewById(R.id.list_view);listview.setAdapter(new MyAdapter());}class MyAdapter extends BaseAdapter{@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return 0;}/** * 缓存的是被遮住的那一行 */@Overridepublic View getView(int position, View convertView, ViewGroup parent) {//布局转换器 作用就是讲一个布局转换为一个对象LayoutInflater flater = MainActivity1.this.getLayoutInflater();View view = flater.inflate(R.layout.list_item, null); //真正将一个布局文件转为一个对象//在一个特定的对象上去查找一个ID所对应的组件TextView text_name = (TextView) view.findViewById(R.id.list_view_name);TextView text_age = (TextView) view.findViewById(R.id.list_view_age);Person person = list.get(position);text_name.setText(person.getName());//text_age.setText(person.getAge());text_age.setText(String.valueOf(person.getAge()));return view;}}}</span>