我有一个应用程序,处理片段和ViewPager。我在ViewPager中有三个片段。当你在它们之间切换时,它总是会导致其他两个片段调用它们的onCreateView方法。如何做到这一点,只有当创建FragmentActivity? 我已阅读了一些问题并尝试了解决方案,但片段仍具有相同的行为。为什么片段的onCreateView,onCreate,onActivityCreated被调用
ListFragment onCreate called twice
onCreate() and onCreateView() invokes a lot more than required (Fragments)
下面是一些代码,如果它可以帮助你,伙计们:
MainActivity:
public class StartingActivity extends FragmentActivity implements View.OnClickListener {
ViewPager viewPager;
CirclePageIndicator pageIndicator;
Button discount;
Button qrCode;
Button pay;
TabHost tabHost;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.starting_layout);
viewPager = (ViewPager) findViewById(R.id.pager);
if (savedInstanceState == null) {
Fragment firstPage = Fragment.instantiate(this, FindTovarFragment.class.getName());
Fragment secondPage = Fragment.instantiate(this, MainWindowActivity.class.getName());
Fragment thirdPage = Fragment.instantiate(this, MapActivity.class.getName());
if ((firstPage != null && !firstPage.isDetached())|| (secondPage != null && !secondPage.isDetached()) || (thirdPage != null && !thirdPage.isDetached())) {
List<Fragment> viewPagerFragments = new ArrayList<Fragment>();
viewPagerFragments.add(firstPage);
viewPagerFragments.add(secondPage);
viewPagerFragments.add(thirdPage);
PageAdapter pageAdapter = new PageAdapter(getSupportFragmentManager(), viewPagerFragments);
viewPager.setAdapter(pageAdapter);
pageIndicator = (CirclePageIndicator) findViewById(R.id.circle);
pageIndicator.setViewPager(viewPager);
pageIndicator.setCurrentItem(pageAdapter.getCount() - 2);
}
}
}
MapActivity:
public class MapActivity extends Fragment implements OnMyLocationListener {
//Тэг для логов
private static final String TAG = "MapActivity";
List<Address> addressList;
private static final String STRING_LOCATION = "";
ArrayList<TorgCentr> randomTorgCentr;
ArrayList<String> torgCentrNames;
Context context;
AutoCompleteTextView searchTorgCentr;
OverlayManager overlayManager;
MapController mapController;
TextView textView;
double longitude;
double latitude;
double itemLongitude;
double itemLatitude;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Log.d(TAG, "MapActivity onCreateView");
View view = (LinearLayout) inflater.inflate(R.layout.map_layout, container, false);
final MapView mapView = (MapView) view.findViewById(R.id.map);
textView = (TextView) view.findViewById(R.id.searchlocation);
searchTorgCentr = (AutoCompleteTextView) view.findViewById(R.id.autoCompleteTextView);
mapView.showBuiltInScreenButtons(true);
mapController = mapView.getMapController();
context = getActivity();
return view;
}
@Override
public void onResume() {
super.onResume();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "MapActivity onCreate");
}
public void onActivityCreated(Bundle savedInstanceState) {
Log.d(TAG, "MapActivity onActivityCreated");
context = getActivity();
SetRightMapDisplayAddress rightMapDisplayAddress = new SetRightMapDisplayAddress();
rightMapDisplayAddress.execute(STRING_LOCATION);
DownloadSuperMarketsArray superMarketsArray = new DownloadSuperMarketsArray();
superMarketsArray.execute();
overlayManager = mapController.getOverlayManager();
overlayManager.getMyLocation().setEnabled(false);
super.onActivityCreated(savedInstanceState);
}
二破片换货:
public class MainWindowActivity extends Fragment {
private static final String TAG = "MainWindowActivity";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Log.d(TAG, "MainWindowActivity onCreateView");
View view = (RelativeLayout) inflater.inflate(R.layout.main_window_layout, container, false);
if (container == null) {
return null;
}
return view;
}
}
,第三个:
public class FindTovarFragment extends Fragment {
private static final String TAG= "FindTovarFragment";
Context context;
ArrayList<Category> categories;
Spinner categoryContainer;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Log.d(TAG, "FindTovarFragment onCreateView");
View view = (LinearLayout) inflater.inflate(R.layout.find_tovar_main_layout, container, false);
categoryContainer = (Spinner) view.findViewById(R.id.category);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Log.d(TAG, "FindTovarFragment onActivityCreated");
DownloadCategory downloadCategory = new DownloadCategory();
downloadCategory.execute();
}
日志为MapActivity:
06-20 11:06:37.709: DEBUG/MapActivity(1290): MapActivity onCreate
06-20 11:06:37.709: DEBUG/MapActivity(1290): MapActivity onCreateView
06-20 11:06:38.509: DEBUG/MapActivity(1290): MapActivity onActivityCreated
然后一遍又一遍:
06-20 11:07:53.239: DEBUG/MapActivity(1290): MapActivity onCreate
06-20 11:07:53.239: DEBUG/MapActivity(1290): MapActivity onCreateView
06-20 11:07:53.429: DEBUG/MapActivity(1290): MapActivity onActivityCreated
06-20 11:08:23.029: DEBUG/MapActivity(1290): MapActivity onCreate
06-20 11:08:23.039: DEBUG/MapActivity(1290): MapActivity onCreateView
06-20 11:08:23.269: DEBUG/MapActivity(1290): MapActivity onActivityCreated
预先感谢您非常。
谢谢你的答案。但这正是我所做的。问题是,我的应用程序正在下载大量的信息,当碎片被创建并使用地理定位。所以当一个片段被创建并且另一个片段被viewpager销毁时,它必须再次下载一切,并且如果快速滑动,则应用程序崩溃。所以不可能自定义viewpager,所以它不会销毁对象? – PAcan
另外我不认为不破坏碎片是一个好主意,这是非常糟糕的做法。你应该照顾内存管理,不要这样做...... – jpardogo
请不要再下载一切!将这些信息存储在您的活动中(您只需将一次所需内容下载到您的活动一次),并通过接口形式与片段进行交流。并改变你加载片段的方式,不要创建片段列表或类似的东西,只需从适配器调用newInstance。请仔细阅读android开发者文档,并遵循这些代码,我认为这是最好的主意。将MainWindowActivity,MapActivity重命名为MainWindowFragment,MapFragment也会更清晰。 – jpardogo