Viewpager加Gridview實(shí)現(xiàn)左右滑動翻頁

1、ViewPager+GridView實(shí)現(xiàn)GridView左右滑動翻頁，實(shí)時動態(tài)讀取數(shù)據(jù)實(shí)現(xiàn)思路：給ViewPager動態(tài)加載View，加載ViewPager當(dāng)前最后一個View時預(yù)先判斷是否還有數(shù)據(jù)，如果有就新建一個線程添加一個View，完成根據(jù)滑動及時讀取數(shù)據(jù)。包含兩個文件:main.javaDatabaseHelper.javamain.javapackageyy.viewpagergridview;importjava.util.ArrayList;importjava.util.List;importandroid.app.Activity;importandroid.content.

2、Context;importandroid.database.Cursor;importandroid.database.sqlite.SQLiteDatabase;importandroid.os.Bundle;importandroid.os.Handler;importandroid.os.HandlerThread;importandroid.os.Looper;importandroid.os.Message;importandroid.os.Parcelable;importandroid.support.v4.view.PagerAdapter;importandroid.sup

3、port.v4.view.ViewPager;importandroid.support.v4.view.ViewPager.OnPageChangeListener;importandroid.view.View;importandroid.view.View.OnClickListener;importandroid.widget.GridView;importandroid.widget.SimpleCursorAdapter;importandroid.widget.TextView;importdbhelper.DatabaseHelper;publicclassmainextend

4、sActivityprivateViewPagermyViewPager;privateMyPagerAdaptermyAdapter;privateListmListViews;privateinttolalnum;privateintpagesize=3;/每頁顯示數(shù)量privateDatabaseHelperdbhelper;privateSQLiteDatabasedb;privateCursorcur;privateTextViewgirdviewpage;OverrideprotectedvoidonCreate(BundlesavedInstanceState)/*實(shí)現(xiàn)思路：給V

5、iewPager動態(tài)加載View,加載ViewPager當(dāng)前最后一個View時預(yù)先判斷是否還有數(shù)據(jù)，如果有就新建一個線程添加一個View,完成根據(jù)滑動及時讀取數(shù)據(jù)。*/super.onCreate(savedInstanceState);setContentView(R.layout.main);show();/加載前兩頁GirdViewpublicvoidshow()myAdapter=newMyPagerAdapter();myViewPager=(ViewPager)findViewById(R.id.viewpagerLayout);myViewPager.setAdapter(myA

6、dapter);mListViews=newArrayList();/預(yù)先加載兩個View,及兩頁數(shù)據(jù)，如果考慮實(shí)際情況，可以從倒數(shù)第二個View就開始預(yù)裝數(shù)據(jù)。dbhelper=newDatabaseHelper(main.this,testdata,1);db=dbhelper.getReadableDatabase();cur=db.rawQuery(selectcount(id)asnumfromtesttable,null);cur.moveToFirst();tolalnum=Integer.parseInt(cur.getString(0);if(tolalnum0)girdvi

7、ewpage=(TextView)findViewById(R.id.girdviewpage);/要得到正確的頁數(shù)就自己寫了,這個不是目的,所以需要自己重寫girdviewpage.setText(共有+cur.getString(O)+條數(shù)據(jù)。當(dāng)前第1頁，共+tolalnum/pagesize+頁);/新手,目前沒有找到更合適的方法來拆分Cursorif(tolalnum1)/新建一個線程讀取下一個View的數(shù)據(jù)HandlerThreadhandlerthread=newHandlerThread(GetNewViewThread+arg0);handlerthread.start();m

8、yhandlermh=newmyhandler(handlerthread.getLooper();Messagems=mh.obtainMessage();ms.arg1=arg0+1;ms.sendToTarget();girdviewpage.setText(共有+tolalnum+條數(shù)據(jù)。當(dāng)前第+(argO+l)+頁，共+tolalnum/pagesize+頁);classmyhandlerextendsHandlerpublicmyhandler(Looperlooper)super(looper);OverridepublicvoidhandleMessage(Messagemsg

9、)/TODOAuto-generatedmethodstubsuper.handleMessage(msg);/讀取下一列數(shù)據(jù)intnextnum=msg.arg1;db=dbhelper.getReadableDatabase();cur=db.rawQuery(selectidas_id,namefromtesttableorderbyidLimit+pagesize+Offset+(nextnum)*pagesize,null);/執(zhí)行SQL語句，注意LimitOffset用法if(cur.getCount()0)GridViewgd=newGridView(main.this);mys

10、impcursoradptermyadapter=newmysimpcursoradpter(main.this,R.layout.gridview,cur,newStringname,newintR.id.txtlable1);gd.setAdapter(myadapter);gd.setNumColumns(3);gd.setHorizontalSpacing(1);gd.setVerticalSpacing(1);gd.setColumnWidth(90);gd.setStretchMode(2);/添加viewmListViews.add(gd);db.close();privatec

11、lassMyPagerAdapterextendsPagerAdapterOverridepublicvoiddestroyItem(Viewarg0,intarg1,Objectarg2)(ViewPager)arg0).removeView(mListViews.get(arg1);OverridepublicintgetCount()returnmListViews.size();OverridepublicObjectinstantiateItem(Viewarg0,intarg1)(ViewPager)arg0).addView(mListViews.get(arg1),0);ret

12、urnmListViews.get(arg1);OverridepublicbooleanisViewFromObject(Viewarg0,Objectarg1)returnarg0=(arg1);OverridepublicvoidfinishUpdate(Viewarg0)/TODOAuto-generatedmethodstubOverridepublicvoidrestoreState(Parcelablearg0,ClassLoaderarg1)/TODOAuto-generatedmethodstubOverridepublicParcelablesaveState()/TODO

13、Auto-generatedmethodstubreturnnull;OverridepublicvoidstartUpdate(Viewarg0)/TODOAuto-generatedmethodstubDatabaseHelper.java/數(shù)據(jù)庫操作，初始化數(shù)據(jù)packagedbhelper;importandroid.content.Context;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;importandroid.database.sqlit

14、e.SQLiteDatabase.CursorFactory;/DatabaseHelper作為一個訪問SQLite的助手類，提供兩個方面的功能，/第一，getReadableDatabase(),getWritableDatabase()以獲得SQLiteDatabse對象，通過該對象可以對數(shù)據(jù)庫進(jìn)行操作/第二，提供了onCreate()和onUpgrade()兩個回調(diào)函數(shù)，允許我們在創(chuàng)建和升級數(shù)據(jù)庫時，進(jìn)行自己的操作publicclassDatabaseHelperextendsSQLiteOpenHelperprivatestaticfinalintVERSION=1;/在SQLiteO

15、epnHelper的子類當(dāng)中，必須有該構(gòu)造函數(shù)publicDatabaseHelper(Contextcontext,Stringname,CursorFactoryfactory,intversion)/必須通過super調(diào)用父類當(dāng)中的構(gòu)造函數(shù)super(context,name,factory,version);/TODOAuto-generatedconstructorstubpublicDatabaseHelper(Contextcontext,Stringname)this(context,name,VERSION);publicDatabaseHelper(Contextconte

16、xt,Stringname,intversion)this(context,name,null,version);才會/該函數(shù)是在第一次創(chuàng)建數(shù)據(jù)庫的時候執(zhí)行，實(shí)際上是在第一次得到SQLiteDatabse對象的時候，調(diào)用這個方法OverridepublicvoidonCreate(SQLiteDatabasedb)/TODOAuto-generatedmethodstub/execSQL函數(shù)用于執(zhí)行SQL語句db.execSQL(createtabletesttable(idint，namevarchar(50);for(inti=1;i500;i+)db.execSQL(insertintotesttable(id，name)values(+i+，+i+);Override