SimpleCursorAdapter類是構造方法的定義。
基本介紹
- 中文名：SimpleCursorAdapter類
- 釋義：構造方法的定義
publicSimpleCursorAdapter(Contextcontext,intlayout,Cursorc,String[]from,int[]to)
SimpleCursorAdapter類將一個數據表綁定在ListView上,也就是說,該ListView會顯示數據表的全部記錄.在綁定數據之前,需要先編寫一個SQLiteOpenHelper類的子類,用於運算元據庫,代碼如下
package net.blogjava.mobile.db;
import java.util.Random;
import android.content.Context;
import andorid.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBService extends SQLiteOpenHelper
{
private final static int DATABASE_VERSION = 1;
private final static int DATABASE_NAME = "test.db";
@Override
public void OnCreate(SQLiteDatabase db)
{
String sql = "CREATE TABLE[t_test]("+"[_id]AUTOINC,"
+"[name]VARCHAR(20) NOT NULL ON CONFLICT FAIL,"
+ "CONSTRAINT[sqlite_autoindex_t_test_1] PRIMARY KEY ([_id]))";
db.execSQL(sql);
Random random = new random();
for(int i = 0;i<20;i++)
{
String s = "";
//隨機生成長度為10的字元串
for(int j=0;j<10;j++)
{
char c = (char) (97 + random.nextInt(26));
s += c;
}
//執行insert語句
db.execSQL("insert into t_test(name) values(?)",new Object[]{s});
}
}
public DBService(Context context)
{
super(context,DATABASE_NAME,null,DATABASE_VERSION);
}
//由於不打算對test.db進行升級,因此,在該方法中沒有任何代碼
@Override
public void onUpgrade(SQLiteDatabase db,int oldVersion,int new Version)
{
}
//執行select語句
public Cursor query(String sql,String[] args)
{
SQLiteDataBase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(sql,args);
return cursor;
}
}
