初识 sqlite 与 content provider 学习笔记

NulL. The value is a NulL value.

INTEGER. The value is a signed integer,stored in 1,2,3,4,6,or 8 bytes depending on the magnitude of the value.

REAL. The value is a floating point value,stored as an 8-byte IEEE floating point number.

TEXT. The value is a text string,stored using the database enCoding (UTF-8,UTF-16BE or UTF-16LE).

BLOB. The value is a blob of data,stored exactly as it was input.

把数据类型搞定了…我们就开始使用我们的androID的sqlite了…

                          //创建一个继承sqliteOpenHelper类               publicclassMyOpenHelperextendssqliteOpenHelper{               //必须实现的一个构造方法publicMyOpenHelper(Contextcontext,Stringname,CursorFactoryfactory,intversion){super(context,name,factory,version);               //Todoauto-generatedconstructorstub}               //设置数据库初始化版本号               privatestaticfinalintDATABASE_VERSION=1;               //设置数据库创建的表名               privatestaticfinalStringtable_name="users";               //构建创建表的sql的语句               privatestaticfinalStringtable_CREATE_sql="CREATEtable"+               table_name+"(IDINTEGERprimarykey,nameTEXT)";               //自定义构造方法传入content,与数据库名字               publicMyOpenHelper(Contextcontext,Stringname){this(context,null,DATABASE_VERSION);}               //自定义构造方法传入用来升级数据库的版本号               publicMyOpenHelper(Contextcontext,intversion){               this(context,version);}@OverrIDepublicvoIDonCreate(sqliteDatabasedb){               //Todoauto-generatedmethodstub               Log.d("sqlite","sql-->Createtable"+table_CREATE_sql);               db.execsql(table_CREATE_sql);}               @OverrIDe               publicvoIDonUpgrade(sqliteDatabasedb,intoldVersion,intnewVersion){               //Todoauto-generatedmethodstub}}            

ok

                      //某             String dataBasename = "employee"';             MyOpenHelper moh = new MyOpenHelper(sqlite_contentprovIDerActivity.this,dataBasename );             sqliteDatabase sdb = moh.getReadableDatabase();             toastsql = Toast.makeText(context,"创建数据库成功",Toast.LENGTH_LONG);             toastsql.show();           

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cd /data/data/<package_name>/databases

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3,用sqlite3命令进入数据库

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这样我们就看到我们刚才创建的表了…

这里给出插入 *** 作的代码

                      Stringdatabasename="employee";             MyOpenHelpermoh=newMyOpenHelper(sqlite_contentprovIDerActivity.this,databasename);             //获取一个可写 *** 作             sqliteDatabasesdb=moh.getWritableDatabase();             ContentValuescv=newContentValues();             String[]name={"tom","achai","nevin","week"};             for(inti=0;i<name.length;i++){             cv.put("name",name[i]);             sdb.insert("users",cv);             }          

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剩下的 *** 作…请阅读官方文档sqliteDatabase里面的方法

                              publicclassContentProvIDerData{                 publicstaticfinalStringAUTHORIY="kg.tom.FirstProvIDer";                 publicclassContentProvIDerData{                 //定义我们provIDer使用的认证uri                 publicstaticfinalStringAUTHORIY="kg.tom.FirstProvIDer";                 //定义我们数据库的名字                 publicstaticfinalStringDATABASE_name="kg_tom_pro_test";                 //定义数据库的版本号                 publicstaticfinalintDATABASE_VERSION=1;                 //定义创建表的名字                 publicstaticfinalStringUSERS_table_name="users";                 //实现BaseColums,自带两列,_ID,_count                 publicstaticfinalclassUsertableMetaDataimplementsBaseColumns{                 //定义创建表的名字                 publicstaticfinalStringtable_name="users";                 //定义provIDer的uri                 publicstaticfinalUriCONTENT_URI=Uri.parse("content://"+AUTHORIY+"/users");                 //定义一条数据的类型                 publicstaticfinalStringCONTENT_TYPE="vnd.androID.cursor.dir/vnd.firstprovIDer.user";                 //定义一组数据的类型                 publicstaticfinalStringCONTENT_TYPE_ITEM="vnd.androID.cursor.item/vnd.fiRSStprovIDer.user";                 //定义列名                 publicstaticfinalStringUSER_name="name";                 //定义排序规则                 publicstaticfinalStringDEFulT_SORT_ORDER="_IDdesc";                 }}               

继承这个类我们同时要实现以下几个方法:

query()
insert()
update()
delete()
getType()
onCreate()

还有必须添加一个UriMatcher对象

关于UriMatcher对象的使用文档有很好的解释

                      //定义URI标识符,数值定义请参考文档             publicstaticfinalintINCOMING_USER_ColLECTION=1;             publicstaticfinalintINCOMING_USER_SINGLE=2;             //定义UriMatcher对象             publicstaticfinalUriMatcheruMatcher;             //把标识符加入到URI中,固定写法             static{             uMatcher=newUriMatcher(UriMatcher.NO_MATCH);             //第一个参数为             contentprovIDerauthoriy             uMatcher.addURI(AUTHORIY,"users",INCOMING_USER_ColLECTION);             uMatcher.addURI(AUTHORIY,"users/#",INCOMING_USER_SINGLE);}          

一个完整的content provIDer

                      publicclassFirstProvIDerextendsContentProvIDer{             //定义URI标识符             publicstaticfinalintINCOMING_USER_ColLECTION=1;             publicstaticfinalintINCOMING_USER_SINGLE=2;             //定义UriMatcher对象             publicstaticfinalUriMatcheruMatcher;             //把标识符加入到URI中,固定写法             static{             uMatcher=newUriMatcher(UriMatcher.NO_MATCH);uMatcher.addURI(ContentProvIDerData.AUTHORIY,INCOMING_USER_ColLECTION);             uMatcher.addURI(ContentProvIDerData.AUTHORIY,INCOMING_USER_SINGLE);}             //这里是定义查询用的列名的别名             publicstaticHashMap<String,String>userMap;             privateDataBaseHelperdh;             static{             userMap=newHashMap<String,String>();             userMap.put(UsertableMetaData._ID,"ID");             userMap.put(UsertableMetaData.USER_name,            UsertableMetaData.USER_name);}             @OverrIDe             publicintdelete(Uriuri,Stringselection,String[]selectionArgs){             //Todoauto-generatedmethodstub             return0;}             //根据传入的URI             @OverrIDe             publicStringgetType(Uriuri){             //Todoauto-generatedmethodstub             Log.d("sqlite","getType-->");             switch(uMatcher.match(uri)){             caseINCOMING_USER_ColLECTION:             returnUsertableMetaData.CONTENT_TYPE;             caseINCOMING_USER_SINGLE:             returnUsertableMetaData.CONTENT_TYPE_ITEM;default:             thrownewIllegalArgumentException("unKNownuri"+uri);}}             @OverrIDe             publicUriinsert(Uriuri,ContentValuesvalues){             //Todoauto-generatedmethodstub             Log.d("insert","class"+getClass());             Log.d("insert","content"+getContext());             sqliteDatabasedb=dh.getWritableDatabase();             longrowID=db.insert(UsertableMetaData.table_name,values);             if(rowID>0){             UriinsertUri=ContentUris.withAppendedID             (UsertableMetaData.CONTENT_URI,rowID);             getContext().getContentResolver().notifyChange(insertUri,null);             returninsertUri;}             returnnull;}             @OverrIDe             publicbooleanonCreate(){             //Todoauto-generatedmethodstub             Log.d("sqlite","createPro--->");             dh=newDataBaseHelper(getContext(),ContentProvIDerData.DATABASE_name);             //sqliteDatabasedb=dh.getReadableDatabase();returntrue;}             @OverrIDe             publicCursorquery(Uriuri,String[]projection,            String[]selectionArgs,StringsortOrder){             //Todoauto-generatedmethodstub             sqlitequeryBuilderqb=newsqlitequeryBuilder();             switch(uMatcher.match(uri)){             caseINCOMING_USER_ColLECTION:             qb.settables(UsertableMetaData.table_name);             qb.setProjectionMap(userMap);             break;             caseINCOMING_USER_SINGLE:             qb.settables(UsertableMetaData.table_name);             qb.setProjectionMap(userMap);             qb.appenDWhere(UsertableMetaData._ID+"="+             uri.getPathSegments().get(1));             break;}             StringorderBy;             if(TextUtils.isEmpty(sortOrder)){             orderBy=UsertableMetaData.DEFulT_SORT_ORDER;}else{             orderBy=sortOrder;}             sqliteDatabasedb=dh.getWritableDatabase();             Cursorc=qb.query(db,projection,selection,            selectionArgs,sortOrder);             c.setNotificationUri(getContext().getContentResolver(),uri);             Log.d("sqlite","first--->>");returnc;}             @OverrIDe             publicintupdate(Uriuri,ContentValuesvalues,            String[]selectionArgs){             //Todoauto-generatedmethodstub             return0;}}          

3,在activity中的方法中用上这几行代码就可以进行插入

                      //定义插入用数据的对象,本质是一个             mapContentValuesvalues=newContentValues();             //键,值对values.put("ID",1);             //定义表名             Stringname=ContentProvIDerData.USERS_table_name;             //键值对             values.put(ContentProvIDerData.UsertableMetaData.USER_name,"tom");             //进行contentprovIDer的插入 *** 作             Uriuri=getContentResolver().insert(             ContentProvIDerData.UsertableMetaData.CONTENT_URI,values);          

至于剩下的

query()

delete()

自己参照文档补全吧