Viewpager加Gridview实现左右滑动翻页

1、ViewPager+GridView实现GridView左右滑动翻页，实时动态读取数据实现思路：给ViewPager动态加载View，加载ViewPager当前最后一个View时预先判断是否还有数据，如果有就新建一个线程添加一个View，完成根据滑动及时读取数据。包含两个文件: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;/每页显示数量privateDatabaseHelperdbhelper;privateSQLiteDatabasedb;privateCursorcur;privateTextViewgirdviewpage;OverrideprotectedvoidonCreate(BundlesavedInstanceState)/*实现思路：给V

5、iewPager动态加载View,加载ViewPager当前最后一个View时预先判断是否还有数据，如果有就新建一个线程添加一个View,完成根据滑动及时读取数据。*/super.onCreate(savedInstanceState);setContentView(R.layout.main);show();/加载前两页GirdViewpublicvoidshow()myAdapter=newMyPagerAdapter();myViewPager=(ViewPager)findViewById(R.id.viewpagerLayout);myViewPager.setAdapter(myA

6、dapter);mListViews=newArrayList();/预先加载两个View,及两页数据，如果考虑实际情况，可以从倒数第二个View就开始预装数据。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);/要得到正确的页数就自己写了,这个不是目的,所以需要自己重写girdviewpage.setText(共有+cur.getString(O)+条数据。当前第1页，共+tolalnum/pagesize+页);/新手,目前没有找到更合适的方法来拆分Cursorif(tolalnum1)/新建一个线程读取下一个View的数据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+条数据。当前第+(argO+l)+页，共+tolalnum/pagesize+页);classmyhandlerextendsHandlerpublicmyhandler(Looperlooper)super(looper);OverridepublicvoidhandleMessage(Messagemsg

9、)/TODOAuto-generatedmethodstubsuper.handleMessage(msg);/读取下一列数据intnextnum=msg.arg1;db=dbhelper.getReadableDatabase();cur=db.rawQuery(selectidas_id,namefromtesttableorderbyidLimit+pagesize+Offset+(nextnum)*pagesize,null);/执行SQL语句，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/数据库操作，初始化数据packagedbhelper;importandroid.content.Context;importandroid.database.sqlite.SQLiteDatabase;importandroid.database.sqlite.SQLiteOpenHelper;importandroid.database.sqlit

14、e.SQLiteDatabase.CursorFactory;/DatabaseHelper作为一个访问SQLite的助手类，提供两个方面的功能，/第一，getReadableDatabase(),getWritableDatabase()以获得SQLiteDatabse对象，通过该对象可以对数据库进行操作/第二，提供了onCreate()和onUpgrade()两个回调函数，允许我们在创建和升级数据库时，进行自己的操作publicclassDatabaseHelperextendsSQLiteOpenHelperprivatestaticfinalintVERSION=1;/在SQLiteO

15、epnHelper的子类当中，必须有该构造函数publicDatabaseHelper(Contextcontext,Stringname,CursorFactoryfactory,intversion)/必须通过super调用父类当中的构造函数super(context,name,factory,version);/TODOAuto-generatedconstructorstubpublicDatabaseHelper(Contextcontext,Stringname)this(context,name,VERSION);publicDatabaseHelper(Contextconte

16、xt,Stringname,intversion)this(context,name,null,version);才会/该函数是在第一次创建数据库的时候执行，实际上是在第一次得到SQLiteDatabse对象的时候，调用这个方法OverridepublicvoidonCreate(SQLiteDatabasedb)/TODOAuto-generatedmethodstub/execSQL函数用于执行SQL语句db.execSQL(createtabletesttable(idint，namevarchar(50);for(inti=1;i500;i+)db.execSQL(insertintotesttable(id，name)values(+i+，+i+);Override