移动开发大作业————随手记（数据库和保存到SD卡操作）

保存到SD卡

长按笔记点击保存到SD卡

DBManage.java

package com.cong.notepad;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteException;import android.util.Log;public class DBManage {private Context mContext = null;private SQLiteDatabase mSQLiteDatabase = null;//用于操作数据库的对象private DBHelper dh = null;//用于创建数据库的对象Cursor namecursor=null;private String dbName = "notepad.db";private int dbVersion = 1;public DBManage(Context context){mContext = context;}/** * 打开数据库 */public void open(){try{dh = new DBHelper(mContext, dbName, null, dbVersion);if(dh == null){return ;}mSQLiteDatabase = dh.getWritableDatabase();//dh.onOpen(mSQLiteDatabase);Log.i("log", "DB is opened");}catch(SQLiteException se){se.printStackTrace();Log.i("log", "open DB faile");}}/** * 关闭数据库 */public void close(){mSQLiteDatabase.close();dh.close();Log.i("log", "DB is closed");}//获取列表public Cursor selectAll(){Cursor cursor = null;try{String sql = "select * from travels";cursor = mSQLiteDatabase.rawQuery(sql, null);}catch(Exception ex){ex.printStackTrace();cursor = null;}return cursor;}public Cursor selectById(int id){//String result[] = {};Cursor cursor = null;try{String sql = "select * from travels where _id='" + id +"'";cursor = mSQLiteDatabase.rawQuery(sql, null);}catch(Exception ex){ex.printStackTrace();cursor = null;}return cursor;}public Cursor selcetPathByName(String name){Cursor cursor=null;try{String sql = "select path from icons where filename='"+ name +"'";cursor=mSQLiteDatabase.rawQuery(sql, null);Log.i("log", sql);}catch(Exception ex){ex.printStackTrace();Log.i("log", "select faile");}return cursor;}//插入数据public long insert(String title, String content){Log.i("log", "readyto insert");long datetime = System.currentTimeMillis();Log.i("log", "time------>"+datetime);long l = -1;try{ContentValues cv = new ContentValues();cv.put("title", title);cv.put("content", content);cv.put("time", datetime);Log.i("log", "data----->"+title+content+datetime);l = mSQLiteDatabase.insert("travels", null, cv);Log.i("log", cv.toString());Log.i("log", datetime+""+l);}catch(Exception ex){ex.printStackTrace();l = -1;}return l;}public long inserticonpath(String filename,String iconpath){long l=-1;try{Log.i("log", "ready to insert icon");ContentValues cv = new ContentValues();cv.put("filename",filename);cv.put("path", iconpath);l = mSQLiteDatabase.insert("icons", null, cv);Log.i("log", "insert iconname success");}catch(Exception ex){ex.printStackTrace();l = -1;}return l;}//删除数据public int delete(long id){int affect = 0;try{Log.i("log","try to delete the data in databases");affect = mSQLiteDatabase.delete("travels", "_id=?", new String[]{id+""});Log.i("log", "delete success");}catch(Exception ex){ex.printStackTrace();affect = -1;Log.i("log", "delete faile");}return affect;}//修改数据public int update(int id, String title, String content){int affect = 0;try{ContentValues cv = new ContentValues();cv.put("title", title);cv.put("content", content);affect = mSQLiteDatabase.update("travels", cv, "_id=?", new String[]{id+""});}catch(Exception ex){ex.printStackTrace();affect = -1;}return affect;}}

DBHelper.java

package com.cong.notepad;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class DBHelper extends SQLiteOpenHelper{private String tablename = "travels";private String icontable = "icons";private Context mcontext=null;private String sql = " create table if not exists "+tablename+"(_id integer primary key autoincrement, " +"title varchar," +"content text," +"time varchar)";String sql2 = "create table if not exists "+icontable+"(_id integer primary key autoincrement, " +"filename varchar," +"path varchar)";public DBHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);// TODO Auto-generated constructor stub}@Overridepublic void onCreate(SQLiteDatabase db) {// TODO Auto-generated method stubdb.execSQL(sql);db.execSQL(sql2);}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {// TODO Auto-generated method stub}}