Android 高手進(jìn)階教程(十三)之----Android 數(shù)據(jù)庫SQLiteDatabase的使用！
大家好，好久沒有更新博客了，最近由于身體不適讓大家久等了，好了，直接進(jìn)入主題~
Android 提供了三種數(shù)據(jù)存儲方式，第一種是文件存儲;第二種是SharedPreferences 存儲;第三種就是數(shù)據(jù)庫SQLiteDatabase 存儲。
文件存儲我就不用多說了，而SharedPreferences 可以存取簡單的數(shù)據(jù)(int,double,float.etc)，它經(jīng)常用于數(shù)據(jù)緩存，因?yàn)樗x取存儲簡單。詳細(xì)可以參見本系列。Android 高手進(jìn)階教程(七)之----Android 中Preferences的使用!
今天我們將講一下SQLiteDatabase 的使用。 而掌握SqliteDatabase ，將會我們接下來掌握ContentProvider 打下良好的基石。
為了讓大家更好的掌握，我們手把手完成該節(jié)的Demo 。
第一步：新建一個(gè)Android工程，命名為SQLiteDatabaseDemo.
第二步:創(chuàng)建一個(gè)新的類BooksDB.java?這個(gè)類要繼承于android.database.sqlite.SQLiteOpenHelper抽象類，我們要實(shí)現(xiàn)其中兩個(gè)方法：onCreate(),onUpdate.具體代碼如下：
[java]?view plaincopy package?com.android.tutor;???import?android.content.ContentValues;???import?android.content.Context;???import?android.database.Cursor;???import?android.database.sqlite.SQLiteDatabase;???import?android.database.sqlite.SQLiteOpenHelper;???public?class?BooksDB?extends?SQLiteOpenHelper?{?????????private?final?static?String?DATABASE_NAME?=?"BOOKS.db";?????????private?final?static?int?DATABASE_VERSION?=?1;?????????private?final?static?String?TABLE_NAME?=?"books_table";?????????public?final?static?String?BOOK_ID?=?"book_id";?????????public?final?static?String?BOOK_NAME?=?"book_name";?????????public?final?static?String?BOOK_AUTHOR?=?"book_author";??????????????????public?BooksDB(Context?context)?{???????????//?TODO?Auto-generated?constructor?stub?????????????super(context,?DATABASE_NAME,?null,?DATABASE_VERSION);???????}???????//創(chuàng)建table???????@Override??????public?void?onCreate(SQLiteDatabase?db)?{?????????????String?sql?=?"CREATE?TABLE?"?+?TABLE_NAME?+?"?("?+?BOOK_ID???????????????+?"?INTEGER?primary?key?autoincrement,?"?+?BOOK_NAME?+?"?text,?"+??BOOK_AUTHOR?+"?text);";?????????????db.execSQL(sql);???????}???????@Override??????public?void?onUpgrade(SQLiteDatabase?db,?int?oldVersion,?int?newVersion)?{???????????String?sql?=?"DROP?TABLE?IF?EXISTS?"?+?TABLE_NAME;???????????db.execSQL(sql);???????????onCreate(db);???????}??????????????public?Cursor?select()?{???????????SQLiteDatabase?db?=?this.getReadableDatabase();???????????Cursor?cursor?=?db???????????????????.query(TABLE_NAME,?null,?null,?null,?null,?null,?null);???????????return?cursor;???????}???????//增加操作????????public?long?insert(String?bookname,String?author)?????????{???????????SQLiteDatabase?db?=?this.getWritableDatabase();???????????/*?ContentValues?*/??????????ContentValues?cv?=?new?ContentValues();???????????cv.put(BOOK_NAME,?bookname);???????????cv.put(BOOK_AUTHOR,?author);???????????long?row?=?db.insert(TABLE_NAME,?null,?cv);???????????return?row;?????????}????????//刪除操作?????????public?void?delete(int?id)?????????{???????????SQLiteDatabase?db?=?this.getWritableDatabase();???????????String?where?=?BOOK_ID?+?"?=??";???????????String[]?whereValue?={?Integer.toString(id)?};???????????db.delete(TABLE_NAME,?where,?whereValue);?????????}?????????//修改操作?????????public?void?update(int?id,?String?bookname,String?author)?????????{???????????SQLiteDatabase?db?=?this.getWritableDatabase();???????????String?where?=?BOOK_ID?+?"?=??";???????????String[]?whereValue?=?{?Integer.toString(id)?};????????????????????ContentValues?cv?=?new?ContentValues();???????????cv.put(BOOK_NAME,?bookname);???????????cv.put(BOOK_AUTHOR,?author);???????????db.update(TABLE_NAME,?cv,?where,?whereValue);?????????}???}????
第三步:修改main.xml布局如下，由兩個(gè)EditText和一個(gè)ListView組成，代碼如下:
[c-sharp]?view plaincopy
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