总结一下，我的网页浏览中有8页（片段）我会用新页面替换某些页面，但我无法获胜
我的活动
public class AfficherOngletsCategories extends FragmentActivity implements
TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
private ProgressDialog pDialog;
private static final String READ_CATEGORIES_URL = "http://192.168.1.30/GCR2000/SelectCategories.php";
private static final String READ_SOUS_CATEGORIES_URL = "http://192.168.1.30/GCR2000/SelectSousCategories.php";
private static final String TAG_NOM = "nom";
private static final String TAG_CATEGORIES_ID = "categorie_id";
private static final String TAG_SOUS_CATEGORIES_ID = "sousCategorie_id";
private Categorie catObjet = new Categorie();
private ArrayList<HashMap<String,String>> ListCat = null;
private SousCategorie SousCatObjet = new SousCategorie();
private ArrayList<HashMap<String,String>> ListSousCat;
private TabHost mTabHost;
private ViewPager mViewPager;
private HashMap<String, TabInfo> mapTabInfo = new HashMap<String, n
AfficherOngletsCategories.TabInfo>();
private PagerAdapter mPagerAdapter;
Boolean flag = false;
Bundle test;
/**
* Maintains extrinsic info of a tab's construct
*/
private class TabInfo {
private String tag;
private Class<?> clss;
private Bundle args;
private Fragment fragment;
TabInfo(String tag, Class<?> clazz, Bundle args) {
this.tag = tag;
this.clss = clazz;
this.args = args;
}
}
/**
* A simple factory that returns dummy views to the Tabhost
*/
class TabFactory implements TabContentFactory {
private final Context mContext;
/**
* @param context
*/
public TabFactory(Context context) {
mContext = context;
}
/**
* (non-Javadoc)
*
* @see android.widget.TabHost.TabContentFactory#createTabContent(java.lang.String)
*/
public View createTabContent(String tag) {
View v = new View(mContext);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
/**
* (non-Javadoc)
*
* @see android.support.v4.app.FragmentActivity#onCreate(android.os.Bundle)
*/
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Inflate the layout
setContentView(R.layout.activity_main1);
flag = false;
LoadCategories lc= new LoadCategories();
lc.execute();
//Thread t = new Thread(new LoadCategories2());
// t.start();
//Attend la fin AsynTask
try {
lc.get();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//Lancer après AsynTask
UpdateOnglet(savedInstanceState);
}
/**
* (non-Javadoc)
*
* @see android.support.v4.app.FragmentActivity#onSaveInstanceState(android.os.Bundle)
*
*/
protected void onSaveInstanceState(Bundle outState) {
outState.putString("tab", mTabHost.getCurrentTabTag()); // save the tab selected
//outState.putSerializable("listCat", ListCat);
//outState.putSerializable("listSousCat", ListSousCat);
// selected
super.onSaveInstanceState(outState);
}
/*
* (non-Javadoc)
*
* @see android.app.Activity#onRestoreInstanceState(android.os.Bundle)
*/
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
if (savedInstanceState != null) {
this.mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); // set the tab as per the saved state
//ListCat = (ArrayList<HashMap<String, String>>) savedInstanceState.getSerializable("listCat");
//ListSousCat = (ArrayList<HashMap<String, String>>) savedInstanceState.getSerializable("listSousCat");
}
super.onRestoreInstanceState(savedInstanceState);
}
public void updateJSONdata() {
//Récupere la liste des catégories
ListCat = catObjet.updateJSONOnedata(READ_CATEGORIES_URL, TAG_CATEGORIES_ID, TAG_NOM);
//Récupere la liste des sous-catégories
ListSousCat = SousCatObjet.updateJSONOnedata(READ_SOUS_CATEGORIES_URL, TAG_CATEGORIES_ID, TAG_NOM, TAG_SOUS_CATEGORIES_ID);
}
public void UpdateOnglet(Bundle args){
mTabHost = (TabHost) findViewById(android.R.id.tabhost);
mTabHost.setup();
TabInfo tabInfo = null;
Class<?> mfragment =null;
Bundle objetbunble = null;
List<Fragment> fragments = new Vector<Fragment>();
String catName = null;
//Boucle les categories
for ( int i = 0; ListCat.size() > i; i++){
//Affectation de la categorie dans l'onglet
TabSpec ts = mTabHost.newTabSpec(ListCat.get(i).get(TAG_NOM).toString()).setIndicator(ListCat.get(i).get(TAG_NOM).toString());
Boolean flag = true;
//Boucle des sous-categorie
for(int j = 0; ListSousCat.size() > j; j++){
//compare primary key id avec la foreing key pour déterminer si le fragment associé a l'onglet sera une liste ou un gridlayout
if (ListCat.get(i).get(TAG_CATEGORIES_ID).toString().equals(ListSousCat.get(j).get(TAG_CATEGORIES_ID).toString())){
//Affectation du fragment a l'onglet
mfragment = AfficherSousCategories.class;
catName = ListCat.get(i).get(TAG_NOM).toString();
objetbunble = new Bundle();
//Fragment test = null;
objetbunble.putString("sCsousCatId", ListSousCat.get(j).get(TAG_SOUS_CATEGORIES_ID).toString());
objetbunble.putString("sousCatId", ListSousCat.get(j).get(TAG_CATEGORIES_ID).toString());
objetbunble.putString("catId",ListCat.get(i).get(TAG_CATEGORIES_ID));
objetbunble.putBoolean("flag", flag);
objetbunble.putString("tag", ListCat.get(i).get(TAG_NOM).toString());
//args = objetbunble;
// fragments.setArguments(objetbunble);
break;
}else{
//Affectation du fragment a l'onglet
mfragment = AfficherListElem.class;
catName = ListCat.get(i).get(TAG_NOM).toString();
//Créer le bundle pour envoyer variable url caatégorie au fragment AfficherListElem
objetbunble = new Bundle();
//Renvoie l'id de la categorie
objetbunble.putString("catId", ListCat.get(i).get(TAG_CATEGORIES_ID));
objetbunble.putString("tag", ListCat.get(i).get(TAG_NOM).toString());
//args = objetbunble;
}//End if
}//End for ListSousCat
// mTabHost.addTab(ts, mfragment, objetbunble);
//Ajouter le fragment dans le tab
AfficherOngletsCategories.AddTab(this, this.mTabHost, ts,
(tabInfo = new TabInfo(catName, mfragment, args) ) );
//Ajouter tag dans map
this.mapTabInfo.put(tabInfo.tag, tabInfo);
//Ajouter à liste de fragment pour l'adapter
fragments.add(Fragment.instantiate(this, mfragment.getName()));
//répérer la position
//objetbunble.putInt("fragId", fragments.get(i).getId());
//set le bunble dans le frag
fragments.get(i).setArguments(objetbunble);
}//End for listCat
mTabHost.setOnTabChangedListener(this);
//Création de l'adapter
this.mPagerAdapter = new PagerAdapter(super.getSupportFragmentManager(), fragments);
//this.mPagerAdapter.add(fragments);
//mPagerAdapter.notifyDataSetChanged();
this.mViewPager = (ViewPager) super.findViewById(R.id.tabviewpager2);
this.mViewPager.setAdapter(this.mPagerAdapter);
this.mViewPager.setOnPageChangeListener(this);
/*Forcer le scrool horizontal
TabWidget tw = (TabWidget) findViewById(android.R.id.tabs);
LinearLayout ll = (LinearLayout) tw.getParent();
HorizontalScrollView hs = new HorizontalScrollView(this);
hs.setLayoutParams(new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT,
FrameLayout.LayoutParams.WRAP_CONTENT));
ll.addView(hs, 0);
ll.removeView(tw);
hs.addView(tw);
hs.setHorizontalScrollBarEnabled(false);*/
}
/**
* Add Tab content to the Tabhost
*
* @param activity
* @param tabHost
* @param tabSpec
* @param clss
* @param args
*/
private static void AddTab(AfficherOngletsCategories activity,
TabHost tabHost, TabHost.TabSpec tabSpec, TabInfo tabInfo) {
// Attach a Tab view factory to the spec
tabSpec.setContent(activity.new TabFactory(activity));
tabHost.addTab(tabSpec);
}
/**
* (non-Javadoc)
*
* @see android.widget.TabHost.OnTabChangeListener#onTabChanged(java.lang.String)
*/
public void onTabChanged(String tag) {
// TabInfo newTab = this.mapTabInfo.get(tag);
int pos = this.mTabHost.getCurrentTab();
this.mViewPager.setCurrentItem(pos);
}
/*
* (non-Javadoc)
*
* @see
* android.support.v4.view.ViewPager.OnPageChangeListener#onPageScrolled
* (int, float, int)
*/
int x = 0;
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
// TODO Auto-generated method stub
x = position;
}
/*
* (non-Javadoc)
*
* @see
* android.support.v4.view.ViewPager.OnPageChangeListener#onPageSelected
* (int)
*/
@Override
public void onPageSelected(int position) {
// TODO Auto-generated method stub
this.mTabHost.setCurrentTab(position);
//Faire suivre les onglets avec la pageview
HorizontalScrollView hv = (HorizontalScrollView)findViewById(R.id.scrool);
TabWidget tw = (TabWidget)findViewById(android.R.id.tabs);
int ntabs = ListCat.size();
int taille = ((tw.getWidth() / ntabs)-(tw.getWidth() / (ntabs*4)));
if (x < position)hv.scrollBy(taille, 0);
else hv.scrollBy(-taille, 0);
}
/*
* (non-Javadoc)
*
* @see android.support.v4.view.ViewPager.OnPageChangeListener#
* onPageScrollStateChanged(int)
*/
@Override
public void onPageScrollStateChanged(int state) {
// TODO Auto-generated method stub
}
//exemple thread : new thread = new (new updateJSONdata()).start();
public class LoadCategories2 implements Runnable {
@Override
public void run() {
// TODO Auto-generated method stub
updateJSONdata();
flag = true;
}
}
public class LoadCategories extends AsyncTask<Void, Void, Boolean> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AfficherOngletsCategories.this);
pDialog.setMessage("Loading Comments...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected Boolean doInBackground(Void... arg0) {
updateJSONdata();
return null;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
pDialog.dismiss();
}
}
}
我的pageAdapter
/**
* The <code>PagerAdapter</code> serves the fragments when paging.
*/
public class PagerAdapter extends FragmentPagerAdapter {
FragmentTransaction transaction;
private List<Fragment> fragments;
private Fragment mFragmentAtPos0 ;
/**
* @param fm
* @param fragments
*/
public PagerAdapter(FragmentManager fm, List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
public void add(List<Fragment> fragments){
for (int i = 0; fragments.size() > i; i++){
transaction = fragments.get(i).getFragmentManager().beginTransaction();
//mPagerAdapter.getItem(poss).d
//AfficherSousCategories
transaction.add(R.id.pagercontent, fragments.get(i));
//transaction.hide(AfficherSousCategories.this);
//transaction.show(list);
//getActivity().
//transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
//transaction.remove(arg0)
transaction.addToBackStack(null);
transaction.commit();
}
}
/* (non-Javadoc)
* @see android.support.v4.app.FragmentPagerAdapter#getItem(int)
*/
@Override
public Fragment getItem(int position) {
Log.i("getitem", this.fragments.get(position) + " "+position);
return this.fragments.get(position);
}
/* (non-Javadoc)
* @see android.support.v4.view.PagerAdapter#getCount()
*/
@Override
public int getCount() {
return this.fragments.size();
}
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}
这是我要替换的作品，在此片段中按照所选类别的子类别创建按钮。一旦用户 单击此片段中的某个类别必须替换为另一个 之前我用了一个而且fragmentTabHost替换了fragmentLayout realContent中的片段，所有这些都工作得很好但是因为我想使用寻呼机视图，所以我不能多说谎。 在viewpager中，我必须替换fragmentAdapter中存在的片段，但我不明白如何。
public class AfficherSousCategories extends Fragment {
private ProgressDialog pDialog;
// testing on Emulator:
public String urlSousCat = "http://192.168.1.30/GCR2000/ListSousCat.php";
public String urlListSousCat = "http://192.168.1.30/GCR2000/ListElemSousCat.php";
//private static final String TAG_SUCCESS = "success";
//private static final String TAG_TITLE = "title";
Intent monIntent;
Button btn;
//Type d'envoie JSON
private static final String TAG_POSTS = "posts";
// Balise JSON :
private static final String TAG_ELMENT_ID = "elment_id";
private static final String TAG_NOM = "nom";
private static final String TAG_DESCRIPTION = "description";
private static final String TAG_PRIX = "prix";
public String TAG = "sousCat";
private ViewPager mViewPager;
private PagerAdapter mPagerAdapter;
//public static final String TAG = "sousCat";
String sousCatId;
String sousCategorie_id;
String catId;
String url;
android.support.v7.widget.GridLayout buttonContainer;
public ArrayList<HashMap<String, String>> nSousCat;
private ArrayList<HashMap<String,String>> ListSousCat;
Boolean flag = false;
AfficherListElem list;
//String tag;
FragmentTransaction transaction;
int poss;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.grid_sous_categories, container, false);
buttonContainer = (android.support.v7.widget.GridLayout)view.findViewById(R.id.buttonContainer);
mViewPager = (ViewPager) getActivity().findViewById(R.id.tabviewpager2);
return view;
}
public void onStart(){
super.onStart();
//transaction.add(R.id.realtabcontent, list);
if(list !=null){
// mViewPager.setLayoutParams(new TableLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, 1));
transaction = getFragmentManager().beginTransaction();
transaction.show(AfficherSousCategories.this);
transaction.commit();
}
}
public void onStop(){
super.onStop();
//transaction.add(R.id.realtabcontent, list);
if(list !=null){
// mViewPager.setLayoutParams(new TableLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, 1));
transaction = getFragmentManager().beginTransaction();
transaction.hide(list);
transaction.commit();
}
}
@Override
public void onResume() {
// TODO Auto-generated method stub
super.onResume();
//Objet Bindle qui récupérer les données envoyé de l'activity AfficherongletsCatgories
Bundle objetbunble = getArguments();
catId = objetbunble.getString("catId");
sousCatId = objetbunble.getString("sousCatId");
TAG = objetbunble.getString("tag");
flag = objetbunble.getBoolean("flag");
poss = objetbunble.getInt("poss");
new LoadElements().execute();
}
public void updateJSONdata() {
SousCategorie sc = new SousCategorie();
//La list des éléments parser nElemList = reçois un ArrayList<HashMap<String, String>> avec l'url en paramatre
nSousCat = sc.updateListElem(urlSousCat, catId);
}
/**
* Inserts the parsed data into the listview.
*/
private void updateList() {
float pixels = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 175, getResources().getDisplayMetrics());
for (int i = 0; nSousCat.size() > i; i++){
final String nomSouCat = nSousCat.get(i).get("nom").toString();
btn = new Button(getActivity());
btn.setText(nomSouCat);
// sousCategorie_id = nSousCat.get(i).get("souscategorie_id").toString();
btn.setId(Integer.parseInt(nSousCat.get(i).get("souscategorie_id").toString()));
btn.setHeight((int) pixels);
btn.setWidth((int) pixels);
btn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
// monIntent = new Intent(getActivity(), AfficherListElem.class);
Bundle objetbunble = new Bundle();
for (int i = 0; nSousCat.size() > i; i++){
if (v.getId() == Integer.parseInt(nSousCat.get(i).get("souscategorie_id").toString())){
objetbunble.putString("sousCatId", nSousCat.get(i).get("souscategorie_id").toString());
Log.i("index dans if for", nSousCat.get(i).get("souscategorie_id").toString());
break;
}
}
objetbunble.putBoolean("flag", flag);
objetbunble.putString("catId", catId);
objetbunble.putString("tag", nomSouCat);
//Remplacer view pager
// List<Fragment> fragments = new Vector<Fragment>();
//fragments.add(Fragment.instantiate(getActivity(), AfficherListElem.class.getName()));
//fragments.get(0).setArguments(objetbunble);
// mPagerAdapter.getItemPosition(object);
// mPagerAdapter = new PagerAdapter(
// getActivity().getSupportFragmentManager(), fragments);
//
// mViewPager = (ViewPager)getActivity().findViewById(R.id.tabviewpager2);
//mViewPager.setAdapter(mPagerAdapter);
/*
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.tabviewpager2, list.newInstance(flag, catId, nomSouCat));
transaction.addToBackStack(null);
transaction.commit();
*/
list = new AfficherListElem();
list.setArguments(objetbunble);
transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.tabviewpager2, list); //le probleme et ici car je ne sais pas quel R.id utilisé ou je mis prend mal
transaction.addToBackStack(TAG);
transaction.commit();
//mViewPager.setLayoutParams(new TableLayout.LayoutParams(LayoutParams.FILL_PARENT, 0, 0));
//mPagerAdapter.getItem(poss).d
//AfficherSousCategories
//mViewPager.setAdapter(mPagerAdapter);
//transaction.hide(AfficherSousCategories.this);
//transaction.show(list);
//getActivity().
//transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
//transaction.remove(arg0)
//mPagerAdapter.notifyDataSetChanged();
//AfficherSousCategories.this.getView().setVisibility(AfficherSousCategories.this.getView().GONE);
//list.getView().setVisibility(list.getView().VISIBLE);
}
});
buttonContainer.addView(btn);
}//Bouble for
}
public class LoadElements extends AsyncTask<Void, Void, Boolean> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Loading Comments...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected Boolean doInBackground(Void... arg0) {
updateJSONdata();
return null;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
pDialog.dismiss();
updateList();
}
}
}
我的布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<include
android:id="@+id/top"
layout="@layout/barre_info"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_alignParentTop="true"
android:layout_weight="10"
/>
<!-- -->
<TabHost
android:id="@android:id/tabhost"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/top"
>
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<HorizontalScrollView
android:id="@+id/scrool"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fillViewport="true"
android:scrollbars="none">
<TabWidget
android:id="@android:id/tabs"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal" />
</HorizontalScrollView>
<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="0"/>
<android.support.v4.view.ViewPager
android:id="@+id/tabviewpager2"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1"
/>
<FrameLayout
android:id="@+id/pagercontent"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="1">
</FrameLayout>
</LinearLayout>
</TabHost>
<include
android:id="@+id/bottom"
layout="@layout/boutons_user_standard"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="5dp"
android:layout_alignParentBottom="true"
android:layout_weight="10"/>
<!-- -->
</RelativeLayout>
我提前感谢所有花时间阅读我的帖子的人
答案 0 :(得分：0)
我没有时间完全理解您的代码，但这是我的代码，以防您可以使用它：
FragmentStatePagerAdapter（用法说明如下）：
public class DisplayPagerAdapter extends FragmentStatePagerAdapter {
private static final String TAG = "DisplayPagerAdapter";
SparseArray<DisplayFragment> registeredFragments = new SparseArray<DisplayFragment>();
private final Context context;
private final DisplayCoreModule display;
private final FragmentManager fm;
private boolean isAddOrRemoving;
public DisplayPagerAdapter(Context context, FragmentManager fm,
DisplayCoreModule display) {
super(fm);
this.context = context;
this.display = display;
this.fm = fm;
Log.d(TAG, "pages " + display.getPagesCount());
}
public void notifySizeChangingDataSetChange() {
isAddOrRemoving = true;
notifyDataSetChanged();
isAddOrRemoving = false;
}
@Override
public int getCount() {
int count = (display != null && display.getPagesCount() > 0) ? display
.getPagesCount() : 1;
return count;
}
@Override
public int getItemPosition(Object object) {
DisplayFragment frag = (DisplayFragment) object;
if (!display.containsPageId(frag.getPageId())) {
// this will update the 'no information' page with id -1
return POSITION_NONE;
}
if (isAddOrRemoving) {
// recreate all for simplicity
return POSITION_NONE;
}
return POSITION_UNCHANGED;
}
@Override
public Fragment getItem(int position) {
Log.d(TAG, "getItem " + position);
return DisplayFragment.newInstance(position);
}
@Override
public CharSequence getPageTitle(int position) {
if (display != null && display.getPagesCount() > 0) {
return context.getString(R.string.page) + " " + (position + 1);
} else {
return super.getPageTitle(position);
}
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Log.d(TAG, "instantiateItem " + position);
DisplayFragment fragment = (DisplayFragment) super.instantiateItem(
container, position);
registeredFragments.put(position, fragment);
return fragment;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
Log.d(TAG, "destroyItem " + position);
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
public SparseArray<DisplayFragment> getRegisteredFragments() {
return registeredFragments;
}
}
页面是根据DisplayCoreModule的信息生成的。这实际上将页面位置映射到要在每个DisplayFragment上显示的信息，这也是getItem()只需要将位置传递给新的DisplayFragment以显示正确信息的原因。
我可以想象，有一个外部类可以管理每个位置应显示哪些片段。重要的是它是处理外部的＆＃39;到PagerAdapter。
getRegisteredFragment()周围的代码仅用作当前可见片段的句柄（肯定会添加到Activity而不是null），尽管理论上它也可用于获取可见周围的缓存片段分段。请注意，FragmentStatePagerAdapter只添加一些片段，而不是全部，可以使用mViewPager.setOffscreenPageLimit()
添加/删除片段
好的，现在回想一下DisplayCoreModule。此类保持数据的当前状态。现在，每当数据发生变化时，我都会向持有我的ViewPager的Activity发送一个回调函数。这些回调看起来像这样：
/*
* Get the currently visible DisplayFragment in the ViewPager
*
* @see com.turios.activities.listeners.TuriosUICallback#getSelectedDisplayFragment()
*/
@Override
public DisplayFragment getSelectedDisplayFragment() {
return (DisplayFragment) mDisplayPagerAdapter
.getRegisteredFragment(mViewPager.getCurrentItem());
}
/*
* Makes the current DisplayFragment refresh it's information
*
* @see com.turios.activities.listeners.TuriosUICallback#refreshDisplayFragment()
*/
@Override
public void refreshDisplayFragment() {
DisplayFragment displayFragment = getSelectedDisplayFragment();
if (displayFragment != null) {
displayFragment.refreshScreen();
}
}
/*
* A page has been deleted in DisplayCoreModule
* Inform the Viewpager by calling notifySizeChangingDataSetChange
*
* @see com.turios.activities.listeners.TuriosUICallback#pageDeleted(int)
*/
@Override
public void pageDeleted(int page) {
mDisplayPagerAdapter.notifySizeChangingDataSetChange();
deferInvalidation();
if (display.getPagesCount() == 0) {
locationService.stopLoactionUpdates();
wakeScreen.screenRelease();
}
}
/*
* A page has been added
* Inform the Viewpager by calling notifySizeChangingDataSetChange
*
* @see com.turios.activities.listeners.TuriosUICallback#addPage(int)
*/
@Override
public void addPage(final int page) {
tintBackground();
mDisplayPagerAdapter.notifyDataSetChanged();
if (mViewPager.getCurrentItem() == page)
return;
// http://stackoverflow.com/questions/13585396/viewpager-re-instantiates-items-out-of-order-after-screen-rotation
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
mViewPager.setCurrentItem(page);
}
}, ANIMATION_TINTBACKGROUND);
}
/*
* New information has been added to a page
* Tint screen to catch attention and scroll to the newly updated DisplayFragment
*
* @see com.turios.activities.listeners.TuriosUICallback#pageUpdated(int, java.util.List)
*/
@Override
public void pageUpdated(final int page, final List<String> entries) {
tintBackground();
// http://stackoverflow.com/questions/13585396/viewpager-re-instantiates-items-out-of-order-after-screen-rotation
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
if (!(mViewPager.getCurrentItem() == page)) {
mViewPager.setCurrentItem(page);
} else {
invalidateOptionsMenu();
}
DisplayFragment displayFrag = (com.turios.activities.fragments.DisplayFragment) mDisplayPagerAdapter
.getRegisteredFragment(page);
if (displayFrag != null) {
displayFrag.appendEntries(entries);
}
}
}, ANIMATION_TINTBACKGROUND);
}
所以只要＆＃39;模型＆＃39; （DisplayCoreModule）数据随着页面的添加或删除而变化，我唯一需要做的就是更新“显示”数据。 （ViewPager），是致电notifySizeChangingDataSetChange。
addPage只是调用notifyDataSetChanged的原因是我总是将新页面添加到ViewPager的尾部。因此，我不希望ViewPager重新创建所有片段，因为这里没有必要。
notifySizeChangingDataSetChange使ViewPager重新创建所有片段，允许更改顺序，这在添加或删除不是尾部的片段时是必需的。notifyDataSetChanged对getItem使用POSITION_UNCHANGED，它在调用时对性能的影响较小。但是由于无法改变片段的顺序的限制。 这种架构可能不适合您的情况，但它对我有用。
快乐的编码和好运:)）
答案 1 :(得分：0)
适配器调用getItemId(int position)以检查支持position的片段的数据是否已更改。默认实现返回位置。如果在适配器中重写此方法以返回更新数据的不同值，则适配器会知道旧Fragment不再有效。