sqlite simple demo
数据库操作类：package com.amaker.sqlite;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.util.Log;/** * 数据库操作Demo * @author zzl * */public class MyDbAdapter {//创建数据库public static final String DB_NAME = "per.db";//创建表public static final String TABLE_NAME = "pertbl";//表的一些字段public static final String ID = "_id";public static final String NAME = "name";public static final String AGE = "age";//数据库版本号public static final int VERSION = 1;private Context context;private SQLiteDatabase db;private MyDbHelper helper;//无参构造方法public MyDbAdapter(){}//需要传入上下文的构造方法public MyDbAdapter(Context context) {this.context = context;}class MyDbHelper extends SQLiteOpenHelper {public MyDbHelper() {super(context, DB_NAME, null, VERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {String sql = "create table PerTbl(_id integer" +" primary key autoincrement, name text,age integer) ";db.execSQL(sql);}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {db.execSQL("drop table if exists PerTbl");onCreate(db);}}public MyDbHelper open(){helper = new MyDbHelper();db = helper.getWritableDatabase();return helper;}public void close(){if(helper!=null){helper.close();}}/** * 根据sql语句查询 * @param sql* @return */public Cursor getCursorBysql(String sql){ Log.e("select", "getCursorBysql==========dbs");return db.rawQuery(sql, null);}/** * 添加 * @param table * @param contvls * @return */ public long insert(String table,ContentValues contvls){ long row=db.insert(table, null, contvls); return row; } /** * 更新 * @param id * @param table * @param contvls */ public int update(String table,ContentValues contvls,String where,String[] whereValue){ int result=db.update(table, contvls, where, whereValue); return result; } /** * 根据_Id删除 * @param table */ public void delete(int id){ String[] args = {String.valueOf(id)};db.delete(TABLE_NAME, "_id=?", args); }}
Activity中的调用：
package com.amaker.sqlite;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import android.app.Activity;import android.content.ContentValues;import android.database.Cursor;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity implements OnClickListener { private MyDbAdapter dbAdapter; private Button btn_add; private Button btn_delete; private Button btn_update; private Button btn_find; private TextView tv; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); init(); dbAdapter = new MyDbAdapter(this); dbAdapter.open(); } void init(){ tv = (TextView) findViewById(R.id.tv); btn_add = (Button) findViewById(R.id.button1); btn_delete = (Button) findViewById(R.id.button2); btn_update = (Button) findViewById(R.id.button3); btn_find = (Button) findViewById(R.id.button4); btn_add.setOnClickListener(this); btn_delete.setOnClickListener(this); btn_update.setOnClickListener(this); btn_find.setOnClickListener(this); } /** * 添加按钮点击事件 */@Overridepublic void onClick(View v) {switch (v.getId()) {//添加按鈕case R.id.button1:add();Toast.makeText(getApplicationContext(), "添加成功！", Toast.LENGTH_LONG).show();break;//刪除按鈕case R.id.button2:delete();break;//修改按鈕case R.id.button3:update();break;//查找按鈕case R.id.button4:query();break;default:break;}}//数据库的添加方法：public void add(){ContentValues cv = new ContentValues();cv.put("name", "zzl");cv.put("age", 25);dbAdapter.insert(MyDbAdapter.TABLE_NAME, cv);}//数据库更新方法：public void update(){try {ContentValues cv = new ContentValues();cv.put("name", "li_cai_na");String[] values ={"1"};dbAdapter.update(MyDbAdapter.TABLE_NAME, cv, "_id=?", values);} catch (Exception e) {e.printStackTrace();}}//数据库查找方法：public void query(){List<String> list_name = new ArrayList<String>();try {String sql = "select name from pertbl";Cursor myCursor = dbAdapter.getCursorBysql(sql);while (myCursor.moveToNext()) {String str = myCursor.getString(0);list_name.add(str);}myCursor.close();} catch (Exception e) {e.printStackTrace();}if(list_name.size()>0){tv.setText(list_name.get(0));Iterator<String> iterator = list_name.iterator();while(iterator.hasNext()){System.out.println(iterator.next()+"、");}}}//数据库删除方法：public void delete(){try {dbAdapter.delete(3);} catch (Exception e) {e.printStackTrace();}}}
未封装，只是简单学习下，因好久没看代码，都忘了，最近因要用到数据库就看下。
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