以下程式碼為自己參考相關資料，並依個人常用的需求編寫出的常用函數，
包括新建資料庫、新建資料表、清除資料、新增資料到資料庫中、查詢資料 (讀取資料)、篩選查詢資料。
Step 1: 建立資料表並儲存為 DBHelper.java，Android
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "my.db";
private static final int DB_VERSION = 1;
private final static String _TableName = "Invoice_Item_Table"; //<-- table name
public DBHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
final String SQL = "CREATE TABLE IF NOT EXISTS " + _TableName + "( " +
"_id INTEGER PRIMARY KEY AUTOINCREMENT, " +
"_TITLE VARCHAR(50)" + ");";
db.execSQL(SQL);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
final String SQL = "DROP TABLE " + _TableName;
db.execSQL(SQL);
}
}
Step 2: 初始化資料庫變數:
private DBHelper DH = null;
private SQLiteDatabase db;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DH=new DBHelper(this);
db = DH.getWritableDatabase();
}
Step 3: 建立資料庫常用函數:
//Insert New record to Table
private void add(String Title){
ContentValues values = new ContentValues();
values.put("_TITLE", Title.toString());
db.insert("Invoice_Item_Table", null, values);
}
//read data from table
public ArrayList<String> query_db_to_array()
{
list_Item.setAdapter(null);
Cursor cursor = db.rawQuery("select * from Invoice_Item_Table", null);
ArrayList<String> arrayStrings = new ArrayList<String>();
while (cursor.moveToNext()) {
String sItemName=cursor.getString(1);
arrayStrings.add(sItemName);
}
cursor.close();
return arrayStrings;
}
//clear table
public void clear_db()
{
db.execSQL("delete from Invoice_Item_Table");
}
//close db
private void closeDB()
{
DH.close();
}
@Override
protected void onDestroy() {
super.onDestroy();
closeDB();
}
獨家研發/創作 (2)
