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// Ich habe in RecycleView Fragment wie folgt erstellt:Ich erstelle ein RecyclerView in Fragment, aber während des Datenladens behält RecyclerView den Status nicht bei.
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_new_shop, container, false);
recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
stackView = (RelativeLayout) view.findViewById(R.id.stack_view);
firstStack = (CustomImageView) view.findViewById(R.id.firstStack);
secondStack = (CustomImageView) view.findViewById(R.id.secondStack);
thirdStack = (CustomImageView) view.findViewById(R.id.thirdStack);
stackTopGap = view.findViewById(R.id.view);
new Handler().post(new Runnable() {
@Override
public void run() {
firstStack.getLayoutParams().width = stackView.getWidth() - 40;
secondStack.getLayoutParams().width = stackView.getWidth() - 80;
thirdStack.getLayoutParams().width = stackView.getWidth() - 120;
width = thirdStack.getLayoutParams().width;
recyclerView.getLayoutParams().height = recyclerView.getHeight() - (firstStack.getHeight() + stackTopGap.getHeight());
stackView.getLayoutParams().height = firstStack.getHeight();
}
});
recyclerView.setHasFixedSize(true);
linearLayoutManager=new LinearLayoutManager(getActivity()) {
@Override
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
// A good idea would be to create this instance in some initialization method, and just set the target position in this method.
LinearSmoothScroller smoothScroller = new LinearSmoothScroller(getContext()) {
@Override
public PointF computeScrollVectorForPosition(int targetPosition) {
//int yDelta = calculateCurrentDistanceToPosition(targetPosition);
return new PointF(0, 200);
}
// This is the important method. This code will return the amount of time it takes to scroll 1 pixel.
// This code will request X milliseconds for every Y DP units.
@Override
protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
return 7/TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 7, displayMetrics);
}
};
smoothScroller.setTargetPosition(position);
startSmoothScroll(smoothScroller);
}
};
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
@Override
public void onScrolled(final RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
final int positionView = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastVisibleItemPosition();
if (dy > 0) {
if (positionView >= 2) {
final View view = recyclerView.getChildAt(2);
if (view != null && recyclerView.getChildAdapterPosition(view) == positionView) {
TranslateAnimation translateAnimation = new TranslateAnimation(0, 0, 200, 0);
translateAnimation.setAnimationListener(new Animation.AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {
if (counter == 0) {
if (recyclerView.getAdapter().getItemCount() - 4 >= positionView) {
createStackImageView();
}
if (stackView.getChildAt(1) != null) {
//stackView.getChildAt(1).setScaleX(1.5f);
}
counter++;
}
recyclerView.smoothScrollToPosition(positionView);
}
@Override
public void onAnimationEnd(Animation animation) {
view.clearAnimation();
stackView.requestLayout();
stackView.removeView(stackView.getChildAt(1));
stackView.invalidate();
try {
for (int i = 1; i < 4; i++) {
Glide.with(getActivity())
.load(JSONUrl.IMAGE_BASE_URL + imageList.get(positionView + i))
.into((ImageView) stackView.getChildAt(i));
}
} catch (IndexOutOfBoundsException | NullPointerException | IllegalArgumentException ex) {
ex.printStackTrace();
}
counter = 0;
}
@Override
public void onAnimationRepeat(Animation animation) {
}
});
translateAnimation.setDuration(150);
view.setAnimation(translateAnimation);
}
}
for (int i = stackView.getChildCount() - 1; i >= 2; i--) {
ResizeAnimation resizeAnimation = new ResizeAnimation(stackView.getChildAt(i));
resizeAnimation.setHeights(stackView.getChildAt(i).getHeight(), stackView.getChildAt(i - 1).getHeight());
resizeAnimation.setWidths(stackView.getChildAt(i).getWidth(), stackView.getChildAt(i - 1).getWidth());
resizeAnimation.setDuration(200);
stackView.getChildAt(i).startAnimation(resizeAnimation);
}
} else if (dy < 0) {
final int position = ((LinearLayoutManager) recyclerView.getLayoutManager()).findLastVisibleItemPosition();
if (position == imageList.size() - 1) {
stackView.removeView(firstStack);
stackView.addView(firstStack);
stackView.invalidate();
stackView.requestLayout();
stackView.getChildAt(1).setVisibility(View.VISIBLE);
Glide.with(getActivity())
.load(JSONUrl.IMAGE_BASE_URL + imageList.get(imageList.size() - 1))
.into((ImageView) stackView.getChildAt(1));
} else if (position == imageList.size() - 2) {
stackView.removeView(secondStack);
stackView.addView(secondStack);
secondStack.getLayoutParams().height = firstStack.getHeight() - 20;
secondStack.getLayoutParams().width = firstStack.getWidth() - 40;
stackView.invalidate();
stackView.requestLayout();
stackView.getChildAt(2).setVisibility(View.VISIBLE);
Glide.with(getActivity())
.load(JSONUrl.IMAGE_BASE_URL + imageList.get(imageList.size() - 2))
.into((ImageView) stackView.getChildAt(2));
} else if (position == imageList.size() - 3) {
stackView.removeView(thirdStack);
stackView.addView(thirdStack);
thirdStack.getLayoutParams().height = secondStack.getHeight() - 20;
thirdStack.getLayoutParams().width = secondStack.getWidth() - 40;
stackView.invalidate();
stackView.requestLayout();
stackView.getChildAt(3).setVisibility(View.VISIBLE);
Glide.with(getActivity())
.load(JSONUrl.IMAGE_BASE_URL + imageList.get(imageList.size() - 3))
.into((ImageView) stackView.getChildAt(3));
} else {
stackView.removeView(firstStack);
stackView.addView(firstStack);
stackView.invalidate();
stackView.requestLayout();
}
}
}
});
return view;
}
// In validateToken Verfahren Daten von dem json genommen wird und wie folgt festgelegt an Adapter.
private void validateToken() {
final SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
if (new ConnectionManager(getActivity()).isConnectedToInternet()) {
final SweetAlertDialog pDialog = new AlertDIalogMessage().showProgressDialog(getActivity(), "Loading...");
if (sharedPreferences.getString(SharedPrefrenceInfo.IS_TOKEN_VALID, "token_invalid").equals("token_invalid")) {
Utils.setTokenInfo(getActivity(), pDialog, new AccessTokenInfoHolder() {
@Override
public void setAcessTokenInfo(String accessToken, String expires_in, String token_type) {
Log.e("Access Token", accessToken);
new ShopFragmentJson(getActivity()).getShopPageContent(pDialog, sharedPreferences.getString(SharedPrefrenceInfo.TOKEN_TYPE, "") + " " + sharedPreferences.getString(SharedPrefrenceInfo.IS_TOKEN_VALID, ""), new ShopPageContentHolder() {
@Override
public void setErrorShopPageContent(String statusCode, String statusText) {
//do nothing here since the case unauthorized will not arrive for the first time
}
@Override
public void setSuccessShopPageContent(String success, String data) {
if (success.equals("true")) {
shoppageInfoList = getShopPageContent(data);
//set the adapter after loading data from url
final NewShopFragmentAdapter recyclerViewAdapter = new NewShopFragmentAdapter(getActivity(), recyclerView.getHeight(), shoppageInfoList);
recyclerView.setAdapter(recyclerViewAdapter);
pDialog.dismiss();
} else {
pDialog.dismiss();
new AlertDIalogMessage().showErrorDialog(getActivity(), data);
}
}
});
}
});
} else {
new ShopFragmentJson(getActivity()).getShopPageContent(pDialog, sharedPreferences.getString(SharedPrefrenceInfo.TOKEN_TYPE, "") + " " + sharedPreferences.getString(SharedPrefrenceInfo.IS_TOKEN_VALID, ""), new ShopPageContentHolder() {
@Override
public void setErrorShopPageContent(String statusCode, String statusText) {
//this method is invoked when unauthorized response come from server
Utils.setTokenInfo(getActivity(), pDialog, new AccessTokenInfoHolder() {
@Override
public void setAcessTokenInfo(String accessToken, String expires_in, String token_type) {
new ShopFragmentJson(getActivity()).getShopPageContent(pDialog, sharedPreferences.getString(SharedPrefrenceInfo.TOKEN_TYPE, "") + " " + sharedPreferences.getString(SharedPrefrenceInfo.IS_TOKEN_VALID, ""), new ShopPageContentHolder() {
@Override
public void setErrorShopPageContent(String statusCode, String statusText) {
//do nothing here since the case unauthorized will not arrive for the first time
}
@Override
public void setSuccessShopPageContent(String success, String data) {
if (success.equals("true")) {
List<ShoppageInfo> shoppageInfoList = getShopPageContent(data);
final NewShopFragmentAdapter recyclerViewAdapter = new NewShopFragmentAdapter(getActivity(), recyclerView.getHeight(), shoppageInfoList);
recyclerView.setAdapter(recyclerViewAdapter);
pDialog.dismiss();
} else {
pDialog.dismiss();
new AlertDIalogMessage().showErrorDialog(getActivity(), data);
}
}
});
}
});
}
@Override
public void setSuccessShopPageContent(String success, String data) {
if (success.equals("true")) {
List<ShoppageInfo> shoppageInfoList = getShopPageContent(data);
//set the adapter after loading data from url
final NewShopFragmentAdapter recyclerViewAdapter = new NewShopFragmentAdapter(getActivity(), recyclerView.getHeight(), shoppageInfoList);
recyclerView.setAdapter(recyclerViewAdapter);
pDialog.dismiss();
} else {
pDialog.dismiss();
new AlertDIalogMessage().showErrorDialog(getActivity(), data);
}
}
});
}
} else {
new SweetAlertDialog(getActivity(), SweetAlertDialog.ERROR_TYPE)
.setTitleText("Oops...")
.setContentText("No internet connection!")
.show();
}
}
Nein in onResume Methode namens i Validate-Token wie folgt:
@Override
public void onResume() {
super.onResume();
validateToken();
}
// Nun, wenn ich eine gewisse Aktivität von diesem Fragment rufen und wieder mit Rücken gedrückt Validate-Methode wird aufgerufen und RecyclerView Adapter neu geladen. Nun möchte ich den Zustand von RecyclerView beibehalten, so dass RecyclerView nach der Rückkehr aus der Aktivität in der Scroll-Position bleibt, wenn die Aktivität aufgerufen wird. Aber Problem für mich ist es immer von Anfang an. Ich sehe auch einige Stack Overflow Beiträge und sie empfehlen mir, Parceable zu benutzen, aber ich bekomme keinen Vorteil. Tut nichts.