I have a landscape configuration for one of my app's activities. This activity contains a fragment and this fragment contains one textview and one recyclerview. Everytime when i switch in between portrait and landscape modes, the recyclerview leaves the view of itself like however it was before i turned the device. It might be a little difficult to understand what i try to ask here, so i recorded a gif for that.
https://giphy.com/gifs/3Wv7NAtT8ezP1SQhDu
This is my activity
public class RecipeStepsActivity extends AppCompatActivity {
static Recipe recipe;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recipe_steps);
if (StepDetailActivity.SDA_TAG.equals(StepDetailActivity.NEGATIVE))
recipe = getIntent().getParcelableExtra("recipe");
Bundle b = new Bundle();
b.putParcelable("recipe", recipe);
ActionBar ab = getSupportActionBar();
if (ab != null)
ab.setTitle(recipe.getName());
RecipeStepsFragment recipeStepsFragment = new RecipeStepsFragment();
recipeStepsFragment.setArguments(b);
FragmentManager fm = getSupportFragmentManager();
fm.beginTransaction().add(R.id.frame_layout_steps, recipeStepsFragment).commit();
}
}
This is my fragment
public class RecipeStepsFragment extends Fragment {
#BindView(R.id.recipe_steps_rv)
RecyclerView recyclerView;
#BindView(R.id.ingredients_tv)
TextView tv_ingredients;
List<Step> steps;
public RecipeStepsFragment(){}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_recipe_steps, container, false);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ButterKnife.bind(this, view);
List<Ingredients> ingredients;
Recipe recipe = getArguments().getParcelable("recipe");
steps = recipe.getSteps();
initRecyclerView();
ingredients = recipe.getIngredients();
String ingredientsAppended = "INGREDIENTS" + "\n\n";
if (ingredients == null){
ingredientsAppended = "Not Available";
} else {
for (int a = 0 ; a < ingredients.size() ; a++) {
Ingredients i = ingredients.get(a);
ingredientsAppended += String.valueOf(i.getQuantity()) + " " +
i.getMeasure() + " " +
i.getIngredient();
if (a+1 != ingredients.size()){
ingredientsAppended += '\n';
}
}
}
tv_ingredients.setText(ingredientsAppended);
if(savedInstanceState != null){
recyclerView.scrollToPosition(savedInstanceState.getInt("position"));
}
}
#Override
public void onSaveInstanceState(#NonNull Bundle outState) {
outState.putInt("position", recyclerView.getVerticalScrollbarPosition());
super.onSaveInstanceState(outState);
}
private void initRecyclerView(){
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL));
RecipeStepsRecyclerAdapter recipeStepsRecyclerAdapter =
new RecipeStepsRecyclerAdapter(steps, new RecipeStepsRecyclerAdapter.ClickListener() {
#Override
public void onItemClick(int clickedItemPosition) {
Intent intentToStepDetail = new Intent(getActivity(), StepDetailActivity.class);
Step step = steps.get(clickedItemPosition);
intentToStepDetail.putExtra("step", step);
startActivity(intentToStepDetail);
}
}, getContext());
recyclerView.setAdapter(recipeStepsRecyclerAdapter);
recipeStepsRecyclerAdapter.notifyDataSetChanged();
}
}
This is my adapter
public class RecipeStepsRecyclerAdapter extends RecyclerView.Adapter<RecipeStepsRecyclerAdapter.ViewHolder> {
private List<Step> stepList;
private LayoutInflater mInflater;
final private ClickListener clickListener;
public RecipeStepsRecyclerAdapter(List<Step> stepList, ClickListener clickListener, Context context){
this.stepList = stepList;
this.clickListener = clickListener;
mInflater = LayoutInflater.from(context);
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recipe_steps_recyclerview_adapter, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
Step step = stepList.get(position);
String stepContent = step.getShortDescription();
holder.listingNumber.setText(String.valueOf(position+1));
holder.stepContent.setText(stepContent);
}
#Override
public int getItemCount() {
return stepList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
TextView listingNumber;
TextView stepContent;
private ViewHolder(View itemView) {
super(itemView);
listingNumber = itemView.findViewById(R.id.list_number_tv);
stepContent = itemView.findViewById(R.id.step_content_tv);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
int clickedPosition = getAdapterPosition();
clickListener.onItemClick(clickedPosition);
}
}
public interface ClickListener{
void onItemClick(int clickedItemPosition);
}
}
Layout files are as I already explained above. I guess nothing special to post here.
Thanks in advance.
The problem is that you add a new fragment to the Activity every time it is created. Here's the end of your onCreate(...):
RecipeStepsFragment recipeStepsFragment = new RecipeStepsFragment();
recipeStepsFragment.setArguments(b);
FragmentManager fm = getSupportFragmentManager();
fm.beginTransaction().add(R.id.frame_layout_steps, recipeStepsFragment).commit();
The FragmentManager keeps a reference to the fragment you add to it even if the host Activity is destroyed. Thus, you keep adding new instances of the RecipeStepsFragment eventually overlaying each other and producing the seen behavior.
Don't worry, the fix is pretty simple: use replace(...) instead of add(...):
fm.beginTransaction().replace(R.id.frame_layout_steps, recipeStepsFragment).commit();
P.S.: Note, however, that replacing the current fragment with a new one every time the host activity is destroyed is not a good idea. You should check either if the savedInstanceState is null (which indicates that it's a non-recreated Activity) or if the given fragment is already added (define a tag when adding the fragment and try finding it in onCreate(...) before replacing the old one).
Every time you change the rotation of the screen your activity is destroyed and recreated. That is the reason why your list is populating with new items each time when you switch between your orientation.
So it's important you only instantiate your objects once, and not keep recreating them each time your app is recreated. Which then adds them to your list.
You can use onSaveInstanceState and onRestoreInstanceState.
If you want your app to allow orientation change, apply logic so your list don't get new items each time when activity is created.
Put configChanges attribute in your activity in menifest file
<activity android:name=".VideoActivity" android:configChanges="keyboardHidden|orientation|screenSize"/>
Related
I have a BottomNavigationBar with 3 fragments. In the first fragment, I try to put SQLite data into a recyclerview. It works fine except for the fact that I need to switch between the Navigation Bar items in order to see the refreshed recyclerview. When I use a handler with postDelayed however, it does show the refreshed recyclerview if I set around 1 sec of delay. 0.2 secs wont work already.
Even though this is still very generic: is there any best practice for this? It seems to me that I need to use AsyncTask which has been -however- deprecated.
Thanks!
Simon
HomeFragment
public class HomeFragment extends Fragment {
private HomeViewModel homeViewModel;
private Context context;
private CardView cardview;
private LinearLayout.LayoutParams layoutparams;
private TextView textview;
private RelativeLayout relativeLayout;
private myDbAdapter helper;
RecyclerView myView;
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
homeViewModel =
new ViewModelProvider(this).get(HomeViewModel.class);
View root = inflater.inflate(R.layout.fragment_home, container, false);
helper = new myDbAdapter(getContext());
myView = (RecyclerView) root.findViewById(R.id.recyclerview_home);
RecyclerViewAdapter3 adapter = new RecyclerViewAdapter3(new ArrayList<String>(Arrays.asList(helper.classes())));
myView.setHasFixedSize(true);
myView.setAdapter(adapter);
LinearLayoutManager llm = new LinearLayoutManager(getContext());
llm.setOrientation(LinearLayoutManager.VERTICAL);
myView.setLayoutManager(llm);
homeViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {
#Override
public void onChanged(#Nullable String s) {
textView.setText(s);
}
});
return root;
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
public void refresh(View v){
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
public void run() {
myView = (RecyclerView) v.findViewById(R.id.recyclerview_home);
helper = new myDbAdapter(v.getContext());
ArrayList<String> classes = new ArrayList(Arrays.asList(helper.classes()));
ArrayList<String> subClasses = new ArrayList(Arrays.asList(helper.subClasses()));
RecyclerViewAdapter3 adapter = new RecyclerViewAdapter3(classes);
myView.setHasFixedSize(true);
myView.setAdapter(adapter);
LinearLayoutManager llm = new LinearLayoutManager(v.getContext());
llm.setOrientation(LinearLayoutManager.VERTICAL);
myView.setLayoutManager(llm);
}
}, 1000); //time in millis
}
}
RecyclerViewAdapter3
public class RecyclerViewAdapter3 extends RecyclerView.Adapter<RecyclerViewAdapter3.MyViewHolder> {
public ArrayList<String> classArrayList;
public ArrayList<String> subClassArrayList;
myDbAdapter helper;
public RecyclerViewAdapter3(ArrayList<String> classArrayList){
this.classArrayList = classArrayList;
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View listItem = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardview, parent, false);
return new MyViewHolder(listItem);
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.class.setText(classArrayList.get(position));
holder.delete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
helper = new myDbAdapter(v.getContext());
helper.delete(classArrayList.get(position));
HomeFragment homeFragment = new HomeFragment();
homeFragment.refresh(v.getRootView());
}
});
holder.selectButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
}});}
#Override
public int getItemCount() {
return classArrayList.size();
}
public static class MyViewHolder extends RecyclerView.ViewHolder {
private TextView class;
private Button selectButton;
private ImageView delete;
public MyViewHolder(View itemView) {
super(itemView);
class = (TextView)itemView.findViewById(R.id.name);
selectButton = (Button) itemView.findViewById(R.id.selectButton);
delete = (ImageView) itemView.findViewById(R.id.delete);
}
}
}
Thanks for posting your code :)
There are a fair few things that can go wrong in your code as it is right now, and I can't really pinpoint what causes it to work when you use postDelay. I'm going to list a few, which you can look into:
From your onClick() inside your ViewHolder
HomeFragment homeFragment = new HomeFragment();
homeFragment.refresh(v.getRootView());
You should really not instantiate your fragments like this. You can instead pass a callback from your fragment to your adapter (eg.: View.OnClickListener)
You keep re-instantiating your adapter and your helper needlessly. You should create your adapter only once, set it as your recycler view adapter, and save it in a member variable.
Proposed solution
I see that you're already using ViewModel, so you're on a great path for a less error-prone screen, so I suggest that you move your db query-ing logic to your view model. If you're using raw SQLite (instead of Room), you can extend AndroidViewModel, so you'll have access to a context right away. And as you do with your homeViewModel.getText(), you should expose the classes array as live data, observe it, and submit the new list to your adapter.
For submitting your list to your adapter I suggest using ListAdapter, this will provide you a submitList method for submitting the list in the fragment, and inside the adapter, you will have a getItem(int position) method, which you can query inside the onBindViewHolder method.
Inside your fragment, it'll look something like this:
ClassAdapter adapter = null;
View onCreateView(Bundle savedInstanceState) {
super.onCreate(savedInstanceState)
View root = inflater.inflate(R.layout.fragment_home, container, false);
adapter = new ClassAdapter(
new ClassDeleteCallback() {
#Override
void onClassDeleted(Class class) {
// inside view model we can modify db state, than refresh live data
viewModel.deleteClass(class);
}
},
new ClassSelectedCallback() {
// follows same pattern of above
}
);
RecyclerView rv = root.findViewById(R.id.my_rv);
rv.setAdapter(adapter);
rv.setLayoutManager(new LinearLayoutManager(getContext());
homeViewModel.getClasses().observe(getViewLifecycleOwner(), new Observer<List<Class>>() {
#Override
public void onChanged(#Nullable List<Class> classes) {
adapter.submitList(classes);
}
});
homeViewModel.refreshClasses();
return root;
}
I can highly recommend for you to study this project a bit, because it covers lot of the basics which can lead to a much stabler app: Sunflower sample app
I think you should read a bit more about the architecture components, and then go through some code-labs and stuff, and have another go with this screen starting from square one, because it will be easier than fixing the current state :)
I hope this was helpful, and not too discouraging!
I'm new in android and want an app with viewpager. I am unable to design the viewpager in the layout. The layout fetch the data dynamatically. I want to create a matreial UI viewpager which swipes the page left or right like a paper.I have made a view which shows the data but is unable to swipe like a viewpager left or right...
The code is as below:
public class DetailNewsActivity extends AppCompatActivity {
private PullToZoomScrollViewEx scrollView;
private ArrayList<NewsItemModel> newsArr;
private TextView tvNewsTitle;
private TextView tvNewsPublishDate;
private TextView tvNewsFull;
private int newsPosition = 0;
private ImageView ivYoutubeEnable;
private SharedPreferences sharedPref;
int textSize = 16;
boolean isHighQuality = false;
private Typeface typeface;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail_news);
init();
AdView mAdView = (AdView) findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder()
.addTestDevice("5745FD6726ACCBEE8324DB158D021FA5")
.build();
mAdView.loadAd(adRequest);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_detail_news, container, false);
return view;
}
private void init() {
typeface = Typeface.createFromAsset(getAssets(), "AnmolUni.ttf");
// newsArr = (ArrayList<NewsItemModel>) getIntent().getSerializableExtra("newsArray");
newsArr = AppController.getAppController().getMainNewsArr();
AppController.getAppController().setMainNewsArr(null);
newsPosition = getIntent().getIntExtra("newsPosition", 0);
findViewById(R.id.iv_back).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
findViewById(R.id.iv_share).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
generateBranchURL(newsPosition);
}
});
sharedPref = getSharedPreferences(Constants.SHARED_PREF_NAME, Context.MODE_PRIVATE);
textSize = sharedPref.getInt("text_size", 16);
isHighQuality = sharedPref.getBoolean("isHighQuality",false);
loadViewForCode();
scrollView = (PullToZoomScrollViewEx) findViewById(R.id.scroll_view);
setNewsFromArray(newsPosition);
// ((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom)).setImageResource(android.R.drawable.arrow_down_float);
(scrollView.getZoomView().findViewById(R.id.iv_zoom)).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(DetailNewsActivity.this, ImageVideoActivity.class);
intent.putExtra("viewType", "image");
if(isHighQuality)
intent.putExtra("imageArr", newsArr.get(newsPosition).getImage());
else
intent.putExtra("imageArr", newsArr.get(newsPosition).getMedium());
startActivity(intent);
}
});
DisplayMetrics localDisplayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(localDisplayMetrics);
int mScreenHeight = localDisplayMetrics.heightPixels;
int mScreenWidth = localDisplayMetrics.widthPixels;
LinearLayout.LayoutParams localObject = new LinearLayout.LayoutParams(mScreenWidth, (int) (9.0F * (mScreenWidth / 16.0F)));
scrollView.setHeaderLayoutParams(localObject);
scrollView.setParallax(true);
// scrollView.getPullRootView().findViewById(R.id.container_layout).setOnTouchListener(new OnSwipeTouchListener(DetailNewsActivity.this) {
scrollView.getPullRootView().setOnTouchListener(new OnSwipeTouchListener(DetailNewsActivity.this) {
#Override
public void onSwipeLeft() {
if (newsPosition < newsArr.size() - 1) {
newsPosition++;
setNewsFromArray(newsPosition);
} else {
CommonUtils.showToast(DetailNewsActivity.this, "No more news");
}
}
#Override
public void onSwipeRight() {
if (newsPosition > 0) {
newsPosition--;
setNewsFromArray(newsPosition);
} else {
CommonUtils.showToast(DetailNewsActivity.this, "This is the first news");
}
}
});
scrollView.setOnPullZoomListener(new PullToZoomBase.OnPullZoomListener() {
#Override
public void onPullZooming(int newScrollValue) {
Log.d("MainActivity", "onPullZooming: " + newScrollValue);
// Intent intent = new Intent(DetailNewsActivity.this, ImageVideoActivity.class);
// intent.putExtra("viewType", "image");
// intent.putExtra("imageArr", newsArr.get(newsPosition).getImage());
// startActivity(intent);
}
#Override
public void onPullZoomEnd() {
}
});
}
void setNewsFromArray(int position) {
if (position >= newsArr.size()) {
finish();
return;
}
if (!newsArr.get(position).getMedium().get(0).isEmpty()) {
if(isHighQuality)
Picasso.with(DetailNewsActivity.this).load(newsArr.get(position).getImage().get(0)).placeholder(R.drawable.logo).error(R.drawable.logo).
into((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom));
else
Picasso.with(DetailNewsActivity.this).load(newsArr.get(position).getMedium().get(0)).placeholder(R.drawable.logo).error(R.drawable.logo).
into((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom));
} else {
((ImageView) scrollView.getZoomView().findViewById(R.id.iv_zoom)).setImageResource(R.drawable.logo);
}
tvNewsTitle.setText(newsArr.get(position).getTitle());
tvNewsPublishDate.setText(newsArr.get(position).getPublish_dt());
//String style = "<html><body style='text-align:justify'>";
//Log.i("RAJEEV",style + newsArr.get(position).getFullnews());
tvNewsFull.setText(Html.fromHtml( newsArr.get(position).getFullnews()));
if (newsArr.get(position).getYoutube_video().isEmpty()) {
ivYoutubeEnable.setVisibility(View.GONE);
} else {
ivYoutubeEnable.setVisibility(View.VISIBLE);
}
ivYoutubeEnable.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(DetailNewsActivity.this, ImageVideoActivity.class);
intent.putExtra("viewType", "youtube");
intent.putExtra("youtube_code", newsArr.get(newsPosition).getYoutube_video());
startActivity(intent);
}
});
}
private void loadViewForCode() {
PullToZoomScrollViewEx scrollView = (PullToZoomScrollViewEx) findViewById(R.id.scroll_view);
View headView = LayoutInflater.from(this).inflate(R.layout.ptz_head_view, null, false);
View zoomView = LayoutInflater.from(this).inflate(R.layout.ptz_zoom_view, null, false);
View contentView = LayoutInflater.from(this).inflate(R.layout.ptz_content_view, null, false);
scrollView.setHeaderView(headView);
scrollView.setZoomView(zoomView);
scrollView.setScrollContentView(contentView);
tvNewsTitle = (TextView) scrollView.getPullRootView().findViewById(R.id.tv_news_title);
tvNewsPublishDate = (TextView) scrollView.getPullRootView().findViewById(R.id.tv_news_publish_date);
tvNewsFull = (TextView) scrollView.getPullRootView().findViewById(R.id.tv_news_full);
tvNewsFull.setTextSize(textSize);
if (!AppController.isPunjabiSupported()) {
tvNewsTitle.setTypeface(typeface);
tvNewsFull.setTypeface(typeface);
}
ivYoutubeEnable = (ImageView) scrollView.getHeaderView().findViewById(R.id.iv_youtube_header);
}
void generateBranchURL(final int newsPosition) {
// String imageUrl = "";
// if (newsArr.get(newsPosition).getMedium().size() <= 1)
// imageUrl = newsArr.get(newsPosition).getMedium().get(0);
BranchUniversalObject branchUniversalObject = new BranchUniversalObject()
.setCanonicalIdentifier("NewsDetails")
///.setCanonicalUrl("https://branch.io/deepviews")
//.setTitle("" + newsArr.get(newsPosition).getTitle())
//.setContentDescription("" + newsArr.get(newsPosition).getIntro())
//.setContentImageUrl("" + imageUrl)
// You use this to specify whether this content can be discovered publicly - default is public
.setContentIndexingMode(BranchUniversalObject.CONTENT_INDEX_MODE.PUBLIC);
// Here is where you can add custom keys/values to the deep link data
//.addContentMetadata("property1", "blue")
//.addContentMetadata("property2", "red");
LinkProperties linkProperties = new LinkProperties()
.addControlParameter("$desktop_url", "http://www.newsnumber.com/news/share/" + newsArr.get(newsPosition).getFn_id())
.addControlParameter("$ios_url", "itms-apps://itunes.apple.com/us/app/newsnumber/id1022442357?mt=8")
.addControlParameter("NewsId", "" + newsArr.get(newsPosition).getFn_id())
.addControlParameter("CatId", "" + newsArr.get(newsPosition).getCat_id())
.addControlParameter("$og_title", newsArr.get(newsPosition).getTitle())
.addControlParameter("$og_description", newsArr.get(newsPosition).getIntro())
.addControlParameter("$og_image_url", newsArr.get(newsPosition).getImage().get(0))
.addControlParameter("$twitter_title", newsArr.get(newsPosition).getTitle())
.addControlParameter("$twitter_description", newsArr.get(newsPosition).getIntro())
.addControlParameter("$twitter_image_url", newsArr.get(newsPosition).getImage().get(0))
;
branchUniversalObject.generateShortUrl(this, linkProperties, new Branch.BranchLinkCreateListener() {
#Override
public void onLinkCreate(String url, BranchError error) {
if (error == null) {
Log.i("MyApp", "got my Branch link to share: " + url);
Intent sharingIntent = new Intent(Intent.ACTION_SEND);
sharingIntent.setType("text/plain");
sharingIntent.putExtra(Intent.EXTRA_SUBJECT, "News Number\n");
sharingIntent.putExtra(Intent.EXTRA_TEXT, url);
startActivity(Intent.createChooser(sharingIntent, "Share via"));
}
}
});
}
}
can anyone help??
thanks in advance.
It seems like you might be trying to make a new Activity for each "page" of a ViewPager. The Android support library already has their own ViewPager that uses fragments.
You basically need three things to use a ViewPager:
The ViewPager itself
An adapter for the ViewPager
The fragment that will be used in the ViewPager (esentially the "template" that will be used for each "page" in the ViewPager)
First, we'll create the fragment. This is just a simple example that uses only one TextView, but it will work for any amount of views and data. You'll notice that static method "newInstance()" that creates and returns an instance of this fragment. Google recommends using this method to instantiate new Fragments for a ViewPager as it makes passing data to the fragment much easier. All fragments have a "setArguments()" method that lets you pass in a Bundle when you instantiate it with whatever data you want. The method "getArguments()" can be used to access that bundle and get the values out of it in onCreate() or onCreateView(). This is how you pass in an object or objects to bind its data to the views. In this example, were just passing in a String and setting that String to a TextView. You'll see how it's used when we create the adapter for the ViewPager.
//You should be using android.support.v4.app.Fragment here
public class ExampleFragment extends Fragment {
private static final String DAY_NAME_KEY = "day_name";
private TextView dayName;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View fragmentView = inflater.inflate(R.layout.fragment_example, container, false);
dayName = (TextView) fragmentView.findViewById(R.id.day_name);
return fragmentView;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//Set the name of the day to the dayName TextView
String day = getArguments().getString(DAY_NAME_KEY);
dayName.setText(day);
}
public static ExampleFragment newInstance(String day) {
Bundle bundle = new Bundle();
bundle.putString(DAY_NAME_KEY, day);
ExampleFragment fragment = new ExampleFragment();
fragment.setArguments(bundle);
return fragment;
}
}
Now, we need to make an adapter that will create the views when the ViewPager is swiped. You need to extend either FragmentPagerAdapter or FragmentStatePagerAdapter. FragmentPagerAdapter is used for a small number of static fragments and it will use more memory. So you only want to use this if you have 4 or 5 pages and aren't adding any more dynamically.
For your case, it sounds like you want to swipe through a variable number of pages that are dynamically added, so you want to use FragmentStatePagerAdapter. It's optimized for memory efficiency and it will handle the saving and restoring of the fragments' state for you.
The adapter is simple.
First, you need to make your constructor match the super class's constructor. What that means is that your constructor must have a FragmentManager parameter. All you do with that is pass it to the super class. (You'll see below.)
Secondly, you have to implement just 2 methods from the FragmentStatePagerAdapter class:
public Fragment getItem(int position)
and
public int getCount()
getItem will be automatically called by the ViewPager when it is swiped. You just have to tell it what type of fragment to return. We'll be using the newInstance() method from the ExampleFragment class here.
getCount is the number of views that your ViewPager will be using. For example, I will have an ArrayList that will contain 7 strings (one for each day of the week). I want each one of those strings to be displayed on a different page of my ViewPager. So I'm just going to return the size of the ArrayList for this method.
Here's the class:
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
//A reference to the array of data that will be used to populate
//each fragment. In this case it's an array of Strings, but it
//could be any type of object. The Strings within this array are what
//we'll be passing to the newInstance() method of each fragment.
private ArrayList<String> days;
//Constructor must take a FragmentManager to match the superclass.
public ViewPagerAdapter(FragmentManager fm, ArrayList<String> days) {
//All you have to do with the fragment manager is pass it to super
super(fm);
//The array will be passed in when we create the Adapter in our Activity
this.days = days;
}
#Override
public Fragment getItem(int position) {
/*
Automatically called when another page is needed.
The adapter will keep track of the position of the current page
so the first time this is called, it will be 0, then when a
swipe occurs, it will be one. If it is swiped backward, it will go back to 0.
So when the position is 0, a new Fragment will be created and the
String at days.get(0) ("Monday") will be passed to it.
*/
return ExampleFragment.newInstance(days.get(position));
}
#Override
public int getCount() {
return days.size();
}
}
Now we just have to set the adapter for the ViewPager in our Activity and it will automatically handle swipes for us.
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<String> daysOfWeek = new ArrayList<>();
daysOfWeek.add("Monday");
daysOfWeek.add("Tuesday");
daysOfWeek.add("Wednesday");
daysOfWeek.add("Thursday");
daysOfWeek.add("Friday");
daysOfWeek.add("Saturday");
daysOfWeek.add("Sunday");
ViewPager pager = findViewById(R.id.view_pager);
//Pass the activity's fragmentmanager by calling getSupportFragmentManager().
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager(), daysOfWeek);
pager.setAdapter(adapter);
}
}
This is what we get (I've added some padding and color to make it clear):
As for changing the way the pages "turn" (for example, like a newspaper), you need to look into PageTransformer
Application
I am building an Android application wherein order for certain item will be taken from customers. These order can have 4 different status : Pending, Confirmed, Completed and Cancelled. I have written necessary firebase rule for the same.
My initial design was listing up all the orders in single activity, HomeActivity, and everything looked good. But then I decided to change the design to tabs and viewpager for each status of the order in the same HomeActivity. I am using one of the best library, smart tab layout to generate my views.
Current Design
I planned to keep one single Fragment and update the adapter of recyclerview accordingly.
HomeActivity.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Global.replaceFragmentWithAnimation(new HomeTabFragment(), getSupportFragmentManager(), R.id.frame_container);
}
Global.replaceFragmentWithAnimation is a static method which just replaces the fragment to necessary container.
HomeTabFragment.java
public class HomeTabFragment extends Fragment implements SmartTabLayout.TabProvider {
public HomeTabFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home_tab, container, false);
final ViewPager viewPager = view.findViewById(R.id.viewpager);
final SmartTabLayout viewPagerTab = view.findViewById(R.id.viewpagertab);
viewPagerTab.setCustomTabView(this);
FragmentPagerItems pages = new FragmentPagerItems(getContext());
pages.add(FragmentPagerItem.of("Pending", OrderListsFragment.class));
pages.add(FragmentPagerItem.of("Confirmed", OrderListsFragment.class));
pages.add(FragmentPagerItem.of("Cancelled", OrderListsFragment.class));
pages.add(FragmentPagerItem.of("Completed", OrderListsFragment.class));
FragmentStatePagerItemAdapter adapter = new FragmentStatePagerItemAdapter(
getActivity().getSupportFragmentManager(), pages);
viewPager.setAdapter(adapter);
viewPager.setCurrentItem(0);
viewPagerTab.setViewPager(viewPager);
viewPagerTab.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
}
});
return view;
}
#Override
public View createTabView(ViewGroup container, int position, PagerAdapter adapter) {
LayoutInflater inflater = LayoutInflater.from(container.getContext());
View tab = inflater.inflate(R.layout.custom_tab_icon_and_notification_mark, container, false);
TextView txtTab = tab.findViewById(R.id.txtTitle);
switch (position) {
case 0:
txtTab.setText(getResources().getString(R.string.pending_tab_text));
break;
case 1:
txtTab.setText(getResources().getString(R.string.confirmed_tab_text));
break;
case 2:
txtTab.setText(getResources().getString(R.string.cancelled_tab_text));
break;
case 3:
txtTab.setText(getResources().getString(R.string.completed_tab_text));
break;
default:
throw new IllegalStateException("Invalid pos - " + position);
}
return tab;
}
}
and finally this is my OrderListFragment
OrderListFragment.java
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_order_lists, container, false);
recycler_view_order_list = view.findViewById(R.id.recycler_view_order_list); //declared outside
emptyView = view.findViewById(R.id.empty_view);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
recycler_view_order_list.setItemAnimator(new DefaultItemAnimator());
recycler_view_order_list.setLayoutManager(mLayoutManager);
loadOrders();
return view;
}
public void loadOrders() {
if (recycler_view_order_list != null) {
recycler_view_order_list.setHasFixedSize(true);
}
final DatabaseReference orderTableRef = Global.getDatabase().getReference(Constants.ORDERS_TABLE);
final DatabaseReference customerRef = Global.getDatabase().getReference(Constants.CUSTOMERS_TABLE);
orderTableRef.keepSynced(true);
customerRef.keepSynced(true);
final Query orderList = orderTableRef.orderByChild("status").equalTo("Pending");
//I hardcoded Pending value to make sure everything looks good.
Global.adapter = new FirebaseRecyclerAdapter<Order, OrderItemHolder>(
Order.class,
R.layout.order_item_view,
OrderItemHolder.class,
orderList
) {
#Override
protected void populateViewHolder(final OrderItemHolder viewHolder, final Order model, final int position) {
if(model.getCustId()!=null) {
customerRef.child(model.getCustId()).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
Customers customers = dataSnapshot.getValue(Customers.class);
//set Customer name
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
if ("Pending".equals(model.getStatus())) {
//Some UI updates for Pending
}
if ("Completed".equals(model.getStatus())) {
//Some UI updates for Pending
}
if ("Cancelled".equals(model.getStatus())) {
//Some UI updates for Pending
}
if ("Confirmed".equals(model.getStatus())) {
//Some UI updates for Pending
}
}
}
};
orderTableRef.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (!dataSnapshot.hasChildren())
emptyView.setVisibility(View.VISIBLE);
else
emptyView.setVisibility(View.GONE);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
RecyclerView.AdapterDataObserver mObserver = new RecyclerView.AdapterDataObserver() {
#Override
public void onItemRangeInserted(int positionStart, int itemCount) {
emptyView.setVisibility(View.GONE);
}
#Override
public void onItemRangeRemoved(int positionStart, int itemCount) {
if (Global.adapter.getItemCount() == 0)
emptyView.setVisibility(View.VISIBLE);
else
emptyView.setVisibility(View.GONE);
}
};
Global.adapter.registerAdapterDataObserver(mObserver);
recycler_view_order_list.setAdapter(Global.adapter);
}
Very long code but I've shortened it as much as possible. I've couple of problems here.
The data never gets displayed even though it is fetched in orderList. when debugged, it never hits populateViewHolder of FirebaseRecyclerAdapter. When I did some research on this issue, All I found was to add RecyclerView.AdapterDataObserver and register it to Global.adapter which I've already implemented. I am still confused as in why the data is not fetched. addListenerForSingleValueEvent for orderTableRef hits anyhow and if (!dataSnapshot.hasChildren()) condition within evaluates to false thus hiding emptyView message. Few suggestions from GitHub issue also stated to remove recycler_view_order_list.setHasFixedSize(true); but it did not help either.
How can I pass different order status for different tabs? I tried doing below within:
HomeTabFragment.java
Bundle bundle=new Bundle();
bundle.putString("orderType","Pending");
pages.add(FragmentPagerItem.of("Pending", OrderListsFragment.class,bundle));
bundle.putString("orderType","Confirmed");
pages.add(FragmentPagerItem.of("Confirmed", OrderListsFragment.class,bundle));
bundle.putString("orderType","Cancelled");
pages.add(FragmentPagerItem.of("Cancelled",OrderListsFragment.class,bundle));
bundle.putString("orderType","Completed");
pages.add(FragmentPagerItem.of("Completed", OrderListsFragment.class,bundle));
Overriding FragmentPagerItems's add method and passing budnle with different value for same key but then it ended up passing last value i.e. Completed during every initialization.
Note - FragmentPagerItems is an utility extension available with the tabs library used.
Could anyone point me in the right direction here?
MainActivity on startup add a fragment layout to Relativeview, then i send a data to fragment to add it to ExpandablelistView but my app shows me error that couldn't recognize ExpandablelistView.
MainActivity:
public class MainActivity extends AppCompatActivity implements FragmentAddCatergory.onClickButtonListener {
private FragmentManager manager;
private FragmentTransaction transactionShowList;
private FragmentTransaction transactionAddCatergory;
private FragmentAddCatergory addCatergory;
private FragmentShowCategory showCategory;
private boolean addcategory;
private TextView txtAddCategory;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
manager = getFragmentManager();
transactionShowList = manager.beginTransaction();
showCategory = new FragmentShowCategory();
addCatergory=new FragmentAddCatergory();
transactionShowList.add(R.id.Fragment_container, showCategory);
transactionShowList.commit();
addcategory=false;
txtAddCategory = (TextView) findViewById(R.id.txtaddcategory);
txtAddCategory.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
ChangeFragment();
}
});
}
public void ChangeFragment(){
transactionAddCatergory=manager.beginTransaction();
if (addcategory){
transactionAddCatergory.replace(R.id.Fragment_container,addCatergory);
txtAddCategory.setText("Do you want to see your List?Show me!");
addcategory=false;
}else{
transactionAddCatergory.replace(R.id.Fragment_container,showCategory);
txtAddCategory.setText("Do you want to add a Category?Create One");
addcategory=true;
}
transactionAddCatergory.commit();
}
#Override
public void ClickButton(String group, String child) {
FragmentShowCategory a=new FragmentShowCategory();
a.showExpand(this,group,child);
}}
in last above code i make object from first fragment and send a data and in below code is code of first fragment
public class FragmentShowCategory extends Fragment {
private View view;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
view = inflater.inflate(R.layout.activity_expandable_list_view, container, false);
return view;
}
public void showExpand(Context context, String g, String c) {
Toast.makeText(context, g + " is " + c, Toast.LENGTH_LONG).show();
HashMap<String, List<String>> carsDetails = DataProvider.getInfo(g, c);
List<String> carsBrands = new ArrayList<String>(carsDetails.keySet());
ItemClass adapter = new ItemClass(context, carsDetails, carsBrands);
ExpandableListView list = (ExpandableListView) view.findViewById(R.id.expandList);
list.setAdapter(adapter);
}}
but when i ran my app, i get error that i don't know why in line of:
ExpandableListView list = (ExpandableListView) view.findViewById(R.id.expandList);
i'd appreciate to help me.
Your fragment's view hierarchy is not inflated automatically just because you created an instance of your fragment, as you do in ClickButton. The onCreateView() method that has to be called first in order to inflate your views is part of the fragment's lifecycle. You should let Android instantiate your fragment, and acquire it's instance through the FragmentManager.
This tutorial explains basics about fragments very well.
This type of question is asked many times in SO, I have tried all of them, but couldn't achieve what I actually want. In my app I have Fragment, inside that fragment I have a recycler view. recyclerview would be manipulated by the data which I have got from API.
What I want that when rotation is changed, the app doesn't call the API again. To achieve this I know I have to put the data in onSaveInstanceState, If I want to save a complex object then the class must be implements Parcelable. I have done everything that is recommended, but couldn't achieve what I want.
I am sharing my code here, I have created a simplified example.
Code for SimpleFragment.java
public class SimpleFragment extends Fragment {
RecyclerView recyclerView;
ArrayList<TestModel> testModelList = new ArrayList<TestModel>() ;
SimpleAdapter simpleAdapter;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.simple_fragment, container, false);
recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(mLayoutManager);
simpleAdapter = new SimpleAdapter(getActivity());
recyclerView.setAdapter(simpleAdapter);
if(savedInstanceState != null){
//if this fragment starts after a rotation or configuration change, load the existing model from a parcelable
testModelList = savedInstanceState.getParcelableArrayList("key");
// I have done necessary debug , after rotation , it comes here ,
// but suddenly savedInstanceState becomes null and getTestModelList() get called
}else {
//if this fragment starts for the first time, load the list of model
getTestModelList();
}
simpleAdapter.setModel(testModelList);
return rootView;
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelableArrayList("key",testModelList);
}
public void getTestModelList(){
for (int i=0;i<10;i++){
testModelList.add(new TestModel(i,"test"+i));
}
Toast.makeText(getActivity(),"Called",Toast.LENGTH_SHORT).show();
}
}
layout file for SimpleFragment: simple_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="#+id/recycler"
android:background="#android:color/black"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
Here is code for my data model TestModel.java
public class TestModel implements Parcelable {
String text;
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public TestModel(int number, String text) {
this.text = text;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(this.text);
}
protected TestModel(Parcel in) {
this.text = in.readString();
}
public static final Parcelable.Creator<TestModel> CREATOR
= new Parcelable.Creator<TestModel>() {
public TestModel createFromParcel(Parcel in) {
return new TestModel(in);
}
public TestModel[] newArray(int size) {
return new TestModel[size];
}
};
}
My adapter class: SimpleAdapter.java
public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.ViewHolder> {
Context context;
ArrayList<TestModel> testModels;
public SimpleAdapter(Context context) {
this.context = context;
}
public void setModel(ArrayList<TestModel> model){
this.testModels = model;
notifyDataSetChanged();
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.single_row, viewGroup, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.list_item.setText(testModels.get(position).getText());
}
#Override
public int getItemCount() {
return testModels.size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
TextView list_item;
public ViewHolder(View itemView) {
super(itemView);
list_item = (TextView) itemView.findViewById(R.id.list_item);
}
}
}
Code for single row layout for adapter single_row.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20dp"
android:id="#+id/list_item"
android:textColor="#android:color/white"/>
</LinearLayout>
These are what I have done, and if change the orientation getTestModelList() method in my SimpleFragment is called again, which I want to avoid; in real app scenario this method will do some API call. I want to save the state of ArrayList<TestModel> testModelList.
you need to save state of activity and check it before configuration
follow this code
public class MainActivity extends AppCompatActivity{
private HomeFragment homeFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager fm = getSupportFragmentManager();
if (savedInstanceState == null) {
homeFragment = new HomeFragment();
((fm.beginTransaction()).replace(R.id.mainframe, homeFragment)).commit();
}
}}}
You can save Fragment instance like this in Fragment onCreate method for orientation change to save instance :
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set Instance true
this.setRetainInstance(true);
}
Android recreates your activity whenever the orientation changes. The reason behind this is you may need to change your layout but you can still achieve that with onConfigurationChanged() of the Activity or the Fragment I suggest you to add
android:configChanges="orientation|keyboardHidden|screenSize"
in your manifest file (refer to this and this). This will stop recreation of Activity on Confifuration changes.