终于有时间好好看看数据库了
今天下午自己封装了一个SQLite数据库
留着以后自己用吧
虽然还有许多要修改的地方
贴出代码先
package com.example.testdatabase;
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;
public class DatabaseManager {
private DatabaseHelper dbHelper;
private static final String tableName = "name_table";
public DatabaseManager(Context context){
dbHelper = new DatabaseHelper(context);
}
public SQLiteDatabase getReadDatabase(){
return dbHelper.getReadableDatabase();
}
public void addData(String name, String num){
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("name", name);
cv.put("num", num);
try{
db.insertOrThrow(tableName, null, cv);
db.close();
}catch(Exception e){
e.printStackTrace();
}
}
public void deleteData(String strName){
String sql = "delete from " + tableName + " where name = '"+ strName +"'" ;
SQLiteDatabase db = dbHelper.getWritableDatabase();
try{
db.execSQL(sql);
//db.delete(tableName, "name ='" + strName + "' ", null);
}catch(Exception e){
e.printStackTrace();
}
}
//查找指定数据
public Cursor findData(String strNum){
String sql = "select * from " + tableName + " where num = " + strNum;
SQLiteDatabase db = dbHelper.getReadableDatabase();
Cursor cursor = null;
cursor = db.rawQuery(sql, new String[]{});
return cursor;
}
//删除表
public void deleteTable(){
String sql = "drop table " + tableName;
SQLiteDatabase db = dbHelper.getWritableDatabase();
try{
db.execSQL(sql);
}catch(Exception e){
e.printStackTrace();
}
}
public Cursor viewData(){
SQLiteDatabase db = dbHelper.getReadableDatabase();
String sql = "select * from " + tableName;
Cursor cursor = null;
try{
cursor = db.rawQuery(sql, new String[]{});
}catch(Exception e){
e.printStackTrace();
}
return cursor;
}
private class DatabaseHelper extends SQLiteOpenHelper{
private static final String dbNameString = "database.db";
private static final int db_version = 1;
private static final String nameTableString = "create table " + tableName + "(" + "name VARCHAR(20)," + "num VARCHAR(20)" + ");";
public DatabaseHelper(Context context) {
super(context, dbNameString, null, db_version);
}
public void onCreate(SQLiteDatabase db) {
db.execSQL(nameTableString);
}
@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
}
}
}
//在外部类中调用如下
//如添加数据
DatabaseManager dm = null;
dm = new DatabaseManager(context);
dm.addData("张三", "123456");
