创建数据库并对数据库数据进行操作

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创建数据库

package com.songyan.applock;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class DBHelper extends SQLiteOpenHelper{    public DBHelper(Context context){        super(context,"security.db",null,1);    }    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL("create table applock (_id integer primary key autoincrement,packagename varchar(30))");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {    }}

对数据库数据进行操作

package com.songyan.applock;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import java.util.ArrayList;import java.util.List;public class AppLockDao {    private DBHelper dbHelper;    public AppLockDao(Context context){        dbHelper=new DBHelper(context);    }    public boolean find(String packageName){        boolean result=false;        SQLiteDatabase db=dbHelper.getReadableDatabase();        if(db.isOpen()){            Cursor cursor=db.rawQuery("select packagename from applock where packagename=?",new String[]{packageName});            if(cursor.moveToNext()){                result=true;            }            cursor.close();            db.close();        }        return result;    }    public void add(String packageName){        if(find(packageName)){            return;        }        SQLiteDatabase db=dbHelper.getWritableDatabase();        if(db.isOpen()){            db.execSQL("insert into applock (packagename) values (?)",new Object[]{packageName});            db.close();        }    }    public void delete(String packageName){        SQLiteDatabase db=dbHelper.getWritableDatabase();        if(db.isOpen()){            db.execSQL("delete from applock where packagename = ?",new Object[]{packageName});        }    }    public List<String> getAllPackageName(){        SQLiteDatabase db=dbHelper.getReadableDatabase();        List<String> packageNames=new ArrayList<String>();        if(db.isOpen()){            Cursor cursor=db.rawQuery("select packagename from applock",null);            while(cursor.moveToNext()){                String packageName=cursor.getString(0);                packageNames.add(packageName);            }            cursor.close();            db.close();        }        return packageNames;    }}

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