private String titles[] = new String[]{"今天", "这周", "这月", "今年"};boolean[] fragmentsUpdateFlag = { false, false, false, false };StarFragment todatFragmet=new StarFragment(titles[0],starDetailEntity, AppConstants.TYPE_CONTENT_TODAY);StarFragment weekFragmet=new StarFragment(titles[1],starDetailEntity, AppConstants.TYPE_CONTENT_WEEK);StarFragment monthFragmet=new StarFragment(titles[2],starDetailEntity, AppConstants.TYPE_CONTENT_MONTH);StarFragment yearFragmet=new StarFragment(titles[3],starDetailEntity, AppConstants.TYPE_CONTENT_YEAR);BaseFragment fragments[]={todatFragmet,weekFragmet,monthFragmet,yearFragmet};

@Overridepublic Object instantiateItem(ViewGroup container, int position) {//得到缓存的fragmentFragment fragment= (Fragment) super.instantiateItem(container, position);//获取到tagString fragmentTag=fragment.getTag();if (fragmentsUpdateFlag[position % fragmentsUpdateFlag.length]){//如果这个fragment需要更新android.support.v4.app.FragmentTransaction ft=fm.beginTransaction();//移除旧的fragment
                ft.remove(fragment);//换成新的fragmentfragment = fragments[position % fragments.length];//添加新fragment时必须用前面获得的tag，这点很重要ft.add(container.getId(), fragment, fragmentTag ==null? fragment.getClass().getName()+position : fragmentTag);ft.attach(fragment);ft.commit();//复位更新标志fragmentsUpdateFlag[position % fragmentsUpdateFlag.length] = false;}else{fragment = fragments[position];}return fragment;}

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.ViewGroup;
import com.bingo.cqtimelottery.R;
import com.bingo.cqtimelottery.api.ApiService;
import com.bingo.cqtimelottery.api.RetrofitManager;
import com.bingo.cqtimelottery.base.BaseActivity;
import com.bingo.cqtimelottery.base.BaseFragment;
import com.bingo.cqtimelottery.constants.ApiConstant;
import com.bingo.cqtimelottery.constants.AppConstants;
import com.bingo.cqtimelottery.starfortune.entity.StarDetailEntity;
import com.bingo.cqtimelottery.util.DateUtil;
import java.util.HashMap;
import java.util.Map;
import butterknife.BindView;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;public class StarFortuneDetailActivity extends BaseActivity {@BindView(R.id.tabLayout)TabLayout mTabLayout;@BindView(R.id.viewPager)ViewPager mViewPager;private String titles[] = new String[]{"今天", "这周", "这月", "今年"};boolean[] fragmentsUpdateFlag = {false, false, false, false};StarFragment todatFragmet = new StarFragment(titles[0], starDetailEntity, AppConstants.TYPE_CONTENT_TODAY);StarFragment weekFragmet = new StarFragment(titles[1], starDetailEntity, AppConstants.TYPE_CONTENT_WEEK);StarFragment monthFragmet = new StarFragment(titles[2], starDetailEntity, AppConstants.TYPE_CONTENT_MONTH);StarFragment yearFragmet = new StarFragment(titles[3], starDetailEntity, AppConstants.TYPE_CONTENT_YEAR);BaseFragment fragments[] = {todatFragmet, weekFragmet, monthFragmet, yearFragmet};private String starName;private String starId;public static StarDetailEntity starDetailEntity;StarPagerFragmentAdapter mainAdapter;private Handler mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);if (msg.arg1 == 100) {fragments[0] = new StarFragment(titles[0], starDetailEntity, AppConstants.TYPE_CONTENT_TODAY);fragmentsUpdateFlag[0] = true;mainAdapter.notifyDataSetChanged();}}};public static StarDetailEntity getStarDetailEntity() {return starDetailEntity;}public static void setStarDetailEntity(StarDetailEntity starDetailEntity) {StarFortuneDetailActivity.starDetailEntity = starDetailEntity;}@Overridepublic int getLayoutRes() {return R.layout.activity_star_fortune_detail;}@Overridepublic void onCreateActivity(@Nullable Bundle savedInstanceState) {Bundle bundle = getIntent().getExtras();starName = bundle.getString("starName");starId = bundle.getString("starId");initToolbar(starName);initAdapter();getStarDetailInfo(starId);}private void initAdapter() {mainAdapter = new StarPagerFragmentAdapter(getSupportFragmentManager(), fragments, titles);mViewPager.setAdapter(mainAdapter);mTabLayout.setupWithViewPager(mViewPager);mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {@Overridepublic void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {// arg0 :当前页面，及你点击滑动的页面；arg1:当前页面偏移的百分比；arg2:当前页面偏移的像素位置
            }@Overridepublic void onPageSelected(int position) {// arg0是当前选中的页面的Positionswitch (position) {case 0: //今天break;}}@Overridepublic void onPageScrollStateChanged(int state) {//arg0 ==1的时表示正在滑动，arg0==2的时表示滑动完毕了，arg0==0的时表示什么都没做。
}});}/*** 请求网络数据* @param lotteryid*/private void getStarDetailInfo(String lotteryid) {showLoading();Map<String, String> map = new HashMap<>();map.put("astroid", lotteryid);map.put("date", DateUtil.formateDateString().substring(0, 10));map.put("appkey", ApiConstant.API_KEY);RetrofitManager.getInstance().createReq(ApiService.class).loadStarDetailInfo(map).enqueue(new Callback<StarDetailEntity>() {@Overridepublic void onResponse(Call<StarDetailEntity> call, Response<StarDetailEntity> response) {dismissLoading();if (response.body() != null)starDetailEntity = response.body();//使用Handler发送数据跟新UIMessage message = new Message();message.arg1 = 100;mHandler.sendMessage(message);}@Overridepublic void onFailure(Call<StarDetailEntity> call, Throwable t) {}});}private void replaceTodayFragment() {}public class StarPagerFragmentAdapter<T extends Fragment> extends FragmentPagerAdapter {private BaseFragment[] mList;private String[] mTitles;private StarDetailEntity starDetailEntity;private FragmentManager fm;public StarDetailEntity getStarDetailEntity() {return starDetailEntity;}public void setStarDetailEntity(StarDetailEntity starDetailEntity) {this.starDetailEntity = starDetailEntity;}public StarPagerFragmentAdapter(FragmentManager fm, BaseFragment[] list, String[] titles) {super(fm);this.mList = list;this.mTitles = titles;this.fm = fm;}@Overridepublic Fragment getItem(int position) {Fragment fragment = fragments[position % fragments.length];Log.i("zzccbb", "getItem:position=" + position + ",fragment:"+ fragment.getClass().getName() + ",fragment.tag="+ fragment.getTag());return fragments[position % fragments.length];}@Overridepublic int getItemPosition(Object object) {return POSITION_NONE;}@Overridepublic int getCount() {return mList.length;}@Overridepublic CharSequence getPageTitle(int position) {return mTitles == null ? super.getPageTitle(position) : mTitles[position];}@Overridepublic Object instantiateItem(ViewGroup container, int position) {//得到缓存的fragmentFragment fragment = (Fragment) super.instantiateItem(container, position);//获取到tagString fragmentTag = fragment.getTag();if (fragmentsUpdateFlag[position % fragmentsUpdateFlag.length]) {//如果这个fragment需要更新android.support.v4.app.FragmentTransaction ft = fm.beginTransaction();//移除旧的fragment
                ft.remove(fragment);//换成新的fragmentfragment = fragments[position % fragments.length];//添加新fragment时必须用前面获得的tag，这点很重要ft.add(container.getId(), fragment, fragmentTag == null ? fragment.getClass().getName() + position : fragmentTag);ft.attach(fragment);ft.commit();//复位更新标志fragmentsUpdateFlag[position % fragmentsUpdateFlag.length] = false;}else{　　　　　　　　　　　　fragment = fragments[position];

　　　　　　　　　　}

　　　　　　　　return fragment; 　　　　} 　　} }