1.创建数据库。
<1>.创建继承SQLiteOpenHelper的类，使用该类对数据库进行操作
<2>.在该类中对数据库进行创建修改结构。
public class DbOpenHelper extends SQLiteOpenHelper {
public DbOpenHelper(Context context) {
super(context, "database.db", null, 4);
}
//首次创建数据库时调用的方法
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table person(personid integer primary key autoincrement,name varchar(10))");
}
//数据库版本号更改时执行的方法
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//db.execSQL("alter table person add phone varchar(12) null");
db.execSQL("alter table person add amount Integer null");
}
}
2.对数据库进行操作
<1>创建数据库操作类DBOpenHelper
<2>调用dbopenhelper.getWritableDatabase()对数据库进行操作。
调用dbopenhelper.getReadableDatabase()对数据库进行查询。
返回的是SQLiteDatabase对象，调用该对象的方法对数据库进行操作。
增：
public void insertdb(Person person){
SQLiteDatabase db=dbopenhelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put("name", person.getName());
values.put("phone", person.getPhone());
values.put("amount", person.getAmount());
db.insert("person", "name",values);
//db.execSQL("insert into person(name,phone) values(?,?)",new Object[]{person.getName(),person.getPhone()});
}
删：
public void deletedb(int personid){
SQLiteDatabase db=dbopenhelper.getWritableDatabase();
db.delete("person", "personid=?", new String[]{String.valueOf(personid)});
//db.execSQL("delete from person where personid=?",new Object[]{personid});
}
改：
public void updatedb(Person person){
SQLiteDatabase db=dbopenhelper.getWritableDatabase();
ContentValues values=new ContentValues();
values.put("name", person.getName());
values.put("phone", person.getPhone());
values.put("amount", person.getAmount());
db.update("person", values,"personid=?", new String[]{String.valueOf(person.getPersonid())});
//db.execSQL("update person set name=?,phone=? where personid=?", new Object[]{person.getName(),person.getPhone(),person.getPersonid()});
}
查：
public Person querydb(int personid){
SQLiteDatabase db=dbopenhelper.getReadableDatabase();
//Cursor cursor=db.rawQuery("select * from person where personid=?", new String[]{String.valueOf(personid)});
Cursor cursor=db.query("person", null,"personid=?", new String[]{String.valueOf(personid)}, null, null, null);
Person person=null;
if(cursor.moveToFirst()){
int pid=cursor.getInt(cursor.getColumnIndex("personid"));
String name=cursor.getString(cursor.getColumnIndex("name"));
String phone=cursor.getString(cursor.getColumnIndex("phone"));
int amount=cursor.getInt(cursor.getColumnIndex("amount"));
person=new Person(pid,name,phone,amount);
}
cursor.close();
return person;
}
3.数据的显示:
使用ListView显示
//使用自定义适配器
private void show2() {
List<Person> persons=services.getScrollData(2, 10);
personadapter adapter=new personadapter(this, persons, R.layout.item1);
listview.setAdapter(adapter);
}
//使用SimpleCursorAdapter适配器
private void show1() {
Cursor person_cursor=services.getScrollData_cursor(2, 10);
SimpleCursorAdapter adapter=new SimpleCursorAdapter(this, R.layout.item1,person_cursor, new String[]{"name","phone","amount"}, new int[]{R.id.name,R.id.phone,R.id.amount});
listview.setAdapter(adapter);
}
//使用SimpleAdapter适配器
private void show() {
List<HashMap<String, String>> data=new ArrayList<HashMap<String, String>>();
List<Person> list_person=services.getScrollData(2, 10);
for(Person person : list_person)
{
HashMap<String, String> hash_data=new HashMap<String, String>();
hash_data.put("name", person.getName());
hash_data.put("phone", person.getPhone());
hash_data.put("amount","0");
data.add(hash_data);
}
SimpleAdapter adapter=new SimpleAdapter(this, data, R.layout.item1, new String[]{"name","phone","amount"}, new int[]{R.id.name,R.id.phone,R.id.amount});
listview.setAdapter(adapter);
}
//自定义适配器需要实现BaseAdapter
public class personadapter extends BaseAdapter {
private List<Person> persons;
private int resource;
private LayoutInflater inflater;
public personadapter(Context context,List<Person> persons,int resource)
{
this.persons =persons;
this.resource=resource;
inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public int getCount() {
return persons.size();
}
public Object getItem(int arg0) {
return persons.get(arg0);
}
public long getItemId(int arg0) {
return arg0;
}
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView==null){//缓存的内容，如果为第一页则为空，不然为缓存的内容
convertView=inflater.inflate(resource, null);
}
TextView nameView=(TextView)convertView.findViewById(R.id.name);
TextView phoneView=(TextView)convertView.findViewById(R.id.phone);
TextView amountView=(TextView)convertView.findViewById(R.id.amount);
Person person=persons.get(position);
nameView.setText(person.getName());
phoneView.setText(person.getPhone());
amountView.setText(String.valueOf(person.getAmount()));
return convertView;
}
}