Develop Reference

How to display this type of view in recyclerview?

i use GridLayoutManager to RecyclerView but i require every four row this (provide image) ViewType
give me solution
This type view

Assumning all items have similar views Try This:
GridLayoutManager layoutManager = new GridLayoutManager(DashboardActivity.this, 2);
layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
#Override
public int getSpanSize(int position) {
if (positions you wish to have a different view) {
return 2;
}
return 1;
}
});

RecyclerView supports multiple viewtypes.
Take a look into this:
How to create RecyclerView with multiple view type?
#Override
public int getItemViewType(int position) {
//Every 5th view should be different
return position % 5;
}
#Override
public int getItemCount() {
return 2;
}

Recycler View: I want my recycler view item(rows) to be highlighted after specific interval of time

I want my recycler view rows to be highlighted after a specific interval of time, say after 2 seconds.
Searched all over the internet but no luck so far.

How about, in the recycler adapter OnBindViewHolder method, put a [Handler.postDelayed](https://developer.android.com/reference/android/os/Handler.html#postDelayed(java.lang.Runnable, long)) in which you set the specific time where you want the item to change.
Inside the runner that you pass in the handler, you put in a boolean flag to check if the row will have a different colour/behaviour + a notifyDataSetChanged() in the adapter. (You will have to change your data object to accomodate this new variable)

The question is not very clear. I had two questions in mind that I mentioned in the comment of the question.
Do you want to highlight some specific rows?
Do you want to toggle the highlight after each two seconds?
So I'm going for a general solution for both.
Let us assume the object you're populating in your each row is like the following.
public class ListItem {
int value;
boolean highlight = false;
}
The list of ListItem object can be inserted in an ArrayList to be populated in the RecyclerView. Here is your adapter which may look like this.
// Declare the yourListItems globally in your Activity
List<ListItem> yourListItems = new ArrayList<ListItem>();
populateYourListItems();
public class YourAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
public class YourViewHolder extends RecyclerView.ViewHolder {
private final TextView valueTextView;
private final LinearLayout background;
public YourViewHolder(final View itemView) {
super(itemView);
valueTextView = (TextView) itemView.findViewById(R.id.value_text_view);
background = (LinearLayout) itemView.findViewById(R.id.background);
}
public void bindView(int pos) {
int value = yourListItems.get(pos).value;
boolean isHighlighted = yourListItems.get(pos).hightlight;
valueTextView.setText(value);
// Set the background colour if the highlight value is found true.
if(isHighlighted) background.setBackgroundColor(Color.GREEN);
else background.setBackgroundColor(Color.WHITE);
}
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_activity_log, parent, false);
return new YourViewHolder(v);
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
try {
if (holder instanceof YourViewHolder) {
YourViewHolder vh = (YourViewHolder) holder;
vh.bindView(position);
}
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
public int getItemCount() {
if (yourListItems == null || yourListItems.isEmpty())
return 0;
else
return yourListItems.size();
}
#Override
public int getItemViewType(int position) {
return 1;
}
}
Now when you want to highlight some specific items of your RecyclerView you need to just set the highlight value to true and then call notifyDataSetChanged() to bring into the change in effect.
So you might need a timer like the following which will highlight your rows as per your demand in every two seconds.
// Declare the timer
private Timer highlightTimer;
private TimerTask highlightTimerTask;
highlightTimer = new Timer();
highlightTimerTask = new TimerTask() {
public void run() {
highLightTheListItems();
}
};
highlightTimer.schedule(highlightTimerTask, 2000);
Now implement your highLightTheListItems function as per your need.
public void highLightTheListItems() {
// Modify your list items.
// Call notifyDataSetChanged in your adapter
yourAdapter.notifyDataSetChanged();
}
Hope that helps. Thanks.

Do you mean highlight as in colour the row's background? If so, you could do this in your listViewAdapter
#Override
public View getView(final int position, View row, ViewGroup parent){
if (row==null){
row = LayoutInflater.from(getContext()).inflate(mResource, parent, false);
}
if(foo){
row.setBackgroundColor(getResources().getColor(R.color.translucent_green));
}
else row.setBackgroundColor(Color.TRANSPARENT);
return row;
}
Then in colours.xml
<color name="translucent_green">#667cfc00</color>
The first 2 numbers(66) is the alpha value, ie opacity. The next 6 are RBG in hexadecimal.

How to click on every item in a RecyclerView with Android Espresso

There are posts on how to click on a certain item in a RecyclerView at whatever position you input, but is there a way to click on all the views, especially given the fact that I may not know how many views there will be in the Recycler View.
I thought of getting the number of items in the RecyclerView like in this link but it involves getting the actual RecyclerView from the activity which sometimes is not possible.
I've also seen a block of code like:
public static class RecyclerViewItemCountAssertion implements ViewAssertion { private final int expectedCount;
public RecyclerViewItemCountAssertion(int expectedCount) {
this.expectedCount = expectedCount;
}
#Override
public void check(View view, NoMatchingViewException noViewFoundException) {
if (noViewFoundException != null) {
throw noViewFoundException;
}
RecyclerView recyclerView = (RecyclerView) view;
RecyclerView.Adapter adapter = recyclerView.getAdapter();
assertThat(adapter.getItemCount(), is(expectedCount));
}
}
But i'm unsure of how to manipulate to get the count

So simply in your test:
final View viewById = activityTestRule.getActivity().findViewById(R.id.your_recycler_view_id);
final RecyclerView recyclerView = (RecyclerView) viewById;
final RecyclerView.Adapter adapter = recyclerView.getAdapter();
final int itemsCount = adapter.getItemCount();
So you can iterate through from 0 to itemsCount-1
You can use this class to get recycler view element at position (in your case 0 to itemsCount-1)
public class RecyclerViewMatcher {
private final int recyclerViewId;
public RecyclerViewMatcher(int recyclerViewId) {
this.recyclerViewId = recyclerViewId;
}
public Matcher<View> atPosition(final int position) {
return atPositionOnView(position, -1);
}
public Matcher<View> atPositionOnView(final int position, final int targetViewId) {
return new TypeSafeMatcher<View>() {
Resources resources = null;
View childView;
public void describeTo(Description description) {
String idDescription = Integer.toString(recyclerViewId);
if (this.resources != null) {
try {
idDescription = this.resources.getResourceName(recyclerViewId);
} catch (Resources.NotFoundException var4) {
idDescription = String.format("%s (resource name not found)", recyclerViewId);
}
}
description.appendText("with id: " + idDescription);
}
public boolean matchesSafely(View view) {
this.resources = view.getResources();
if (childView == null) {
RecyclerView recyclerView =
(RecyclerView) view.getRootView().findViewById(recyclerViewId);
if (recyclerView != null && recyclerView.getId() == recyclerViewId) {
childView = recyclerView.findViewHolderForAdapterPosition(position).itemView;
} else {
return false;
}
}
if (targetViewId == -1) {
return view == childView;
} else {
View targetView = childView.findViewById(targetViewId);
return view == targetView;
}
}
};
}}
and use this class like this:
onView(new RecyclerViewMatcher(R.id.your_recycler_view_id)
.atPositionOnView(0, R.id.your_item_body))
.perform(click());
So finally you are able to click all items in your recyclerview. I hope it would help. Cheers.

I'm thinking out loud here, but a couple of things I would try are:
a- Check to see if there is any way to put this in the ViewHolder/RecyclerView Adapter. That really depends on when you want to trigger the click on all items so I'm guessing it won't work for you.
b- Try a while loop with a try/catch for getting the item. This doesn't sound like a good idea from a software engineering best practices perspective, but it should work if your goal is just to get something working.
c- If you can't get the recycler view itself, is there some way you can access the arraylist (or whatever) you used to populate the recyclerView itself?
Some questions:
1- In what cases is it not possible for you to get the actual recycler view? And if you can't get it, then how will you trigger its onclick anyway?
2- Could you maybe share your code and where you need to do this?
disclaimer: I'm a bit new to android development, but I hope this helps.

To be thread safe you should use custom view action something like
#RunWith(AndroidJUnit4.class)
public class XXXXActivityTest {
int count=0;
#Test
public void xxxxxxx() throws Exception {
onView(allOf(withId(R.id.drawer_list))).perform(new ViewAction() {
#Override
public Matcher<View> getConstraints() {
return null;
}
#Override
public String getDescription() {
return null;
}
#Override
public void perform(UiController uiController, View view) {
count=((ListView)view).getAdapter().getCount();
}
});
}
}
then you can iterate with
onView(new RecyclerViewMatcher(R.id.drawer_list)
.atPositionOnView(0, R.id.your_item_body))
.perform(click());
assertThat(.......) for all items

Android:getting number of views in recyclerview

I am implementing recyclerview with multiple layouts.Usually we have multiple viewholders for different layouts and override other methods as per the required layout.I have successfully implemented this.But now i have a different scenario like: A recyclerview that shows some videos (say 3) then another layout(say layout x), again 3 videos and then again layout x and so on.Suppose i have 10 videos then in this case the itemcount would be 10 + 3 as 3 layout x would be displayed.But the videos are loaded while scrolling.So how can i determine the number of views to return in getItemCount();
I mean
#Override
public int getItemCount() {
return ListofVideos.size() + "WHAT??"
}
layout is like this
If all the videos are loaded at at once then it is easy to calculate the number of views like if i have 21 videos i would have total 27 views(i.e 21 videos and 6 layout X views). But when the list is loaded on scroll how can i determine the number of views?

Your Adapter is responsible to populate view so it has all views of your RecyclerView while your ListofVideos (may) have only video links.
Whenever you scroll your RecyclerView, Adapter is responsible to inflate views.
What you should do?
Create an interface
public interface BaseItem {
int ITEM_TYPE_HEADER = 0;
int ITEM_TYPE_SUB_HEADER = 1;
int ITEM_TYPE_ROW_NORMAL = 2;
int getItemType();
}
And implement this interface with your adapter's video item like
public class YourAdapterVideoItem implements BaseItem {
// rest of your code
#Override
public int getItemType() {
return ITEM_TYPE_ROW_NORMAL;
}
}
Create your adapter's header item
public class YourAdapterHeaderItem implements BaseItem {
// rest of your code
#Override
public int getItemType() {
return ITEM_TYPE_HEADER;
}
}
Update your adapter with
public class YourAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<BaseItem> items = new ArrayList<BaseItem>();
#Override
public BaseRecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
BaseRecyclerViewHolder holder;
switch (viewType) {
case BaseItem.ITEM_TYPE_ROW_NORMAL:
default:
// inflate your default items
break;
case BaseItem.ITEM_TYPE_HEADER:
// inflate your default items
break;
}
return holder;
}
#Override
public void onBindViewHolder(BaseRecyclerViewHolder viewHolder, int position) {
BaseItem base = getItemAt(position);
switch (base.getItemType()) {
case BaseItem.ITEM_TYPE_HEADER:
// populate your header view
break;
case BaseItem.ITEM_TYPE_ROW_NORMAL:
// populate your actual view
break;
}
}
#Override
public int getItemCount() {
return items == null ? 0 : items.size();
}
#Override
public int getItemViewType(int position) {
return getItemAt(position).getItemType();
}
public BaseItem getItemAt(int position) {
return items == null ? null : items.get(position);
}
}
When you want to add header use YourAdapterHeaderItem for your videos use YourAdapterVideoItem.
Hope this helps
Edit
For adding headers in GridLayoutManager have a look at RecyclerView GridLayoutManager with full width header

How is the position of a RecyclerView adapter related to the index of its dataset?

I thought they were the same, but they're not. The following code gives an indexOutOfBounds exception when I try to access the "position" index of my dataset, in this case a list of a model I created called Task:
public class TaskAdapter extends RecyclerView.Adapter<TaskAdapter.TaskViewHolder> {
private List<Task> taskList;
private TaskAdapter thisAdapter = this;
// cache of views to reduce number of findViewById calls
public static class TaskViewHolder extends RecyclerView.ViewHolder {
protected TextView taskTV;
protected ImageView closeBtn;
public TaskViewHolder(View v) {
super(v);
taskTV = (TextView)v.findViewById(R.id.taskDesc);
closeBtn = (ImageView)v.findViewById(R.id.xImg);
}
}
public TaskAdapter(List<Task> tasks) {
if(tasks == null)
throw new IllegalArgumentException("tasks cannot be null");
taskList = tasks;
}
// onBindViewHolder binds a model to a viewholder
#Override
public void onBindViewHolder(TaskViewHolder taskViewHolder, int pos) {
final int position = pos;
Task currTask = taskList.get(pos);
taskViewHolder.taskTV.setText(currTask.getDescription());
**taskViewHolder.closeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d("TRACE", "Closing task at position " + position);
// delete from SQLite DB
Task taskToDel = taskList.get(position);
taskToDel.delete();
// updating UI
taskList.remove(position);
thisAdapter.notifyItemRemoved(position);
}
});**
}
#Override
public int getItemCount() {
//Log.d("TRACE", taskList.size() + " tasks in DB");
return taskList.size();
}
// inflates row to create a viewHolder
#Override
public TaskViewHolder onCreateViewHolder(ViewGroup parent, int pos) {
View itemView = LayoutInflater.from(parent.getContext()).
inflate(R.layout.list_item, parent, false);
Task currTask = taskList.get(pos);
//itemView.setBackgroundColor(Color.parseColor(currTask.getColor()));
return new TaskViewHolder(itemView);
}
}
Deleting from my recyclerview gives unexpected results sometimes. Sometimes the element ahead of the one clicked is deleted, other times an indexOutOfBounds exception occurs at "taskList.get(position)".
Reading https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html and https://developer.android.com/training/material/lists-cards.html did not give me any more insight into why this was happening and how to fix it.
It looks like RecyclerView recycles the rows, but I wouldn't expect an indexoutofbounds exception using a smaller subset of numbers to index my list.

RecyclerView does not rebind views when their positions change (for obvious performance reasons).
For example, if your data set looks like this:
A B C D
and you add item X via
mItems.add(1, X);
notifyItemInserted(1, 1);
to get
A X B C D
RecyclerView will only bind X and run the animation.
There is a getPosition method in ViewHolder but that may not match adapter position if you call it in the middle of an animation.
If you need the adapter position, your safest option is getting the position from the Adapter.
update for your comment
Add a Task field to the ViewHolder.
Change onCreateViewHolder as follows to avoid creating a listener object on each rebind.
// inflates row to create a viewHolder
#Override
public TaskViewHolder onCreateViewHolder(ViewGroup parent, int type) {
View itemView = LayoutInflater.from(parent.getContext()).
inflate(R.layout.list_item, parent, false);
final TaskViewHolder vh = new TaskViewHolder(itemView);
taskViewHolder.closeBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// delete from SQLite DB
Task taskToDel = vh.getTask();
final int pos = taskList.indexOf(taskToDel);
if (pos == -1) return;
taskToDel.delete();
// updating UI
taskList.remove(pos);
thisAdapter.notifyItemRemoved(pos);
}
});
}
so in your on bind method, you do
// onBindViewHolder binds a model to a viewholder
#Override
public void onBindViewHolder(TaskViewHolder taskViewHolder, int pos) {
Task currTask = taskList.get(pos);
taskViewHolder.setTask(currTask);
taskViewHolder.taskTV.setText(currTask.getDescription());
}

Like yigit said, RecyclerView works like that:
A B C D
and you add item X via
mItems.add(1, X);
notifyItemInserted(1, 1);
you get
A X B C D
Using holder.getAdapterPosition() in onClickListener() will give you the right item from dataset to be removed, not the "static" view position. Here's the doc about it onBindViewHolder

Why dont you use a public interface for the button click and controle the action in the MainActivity.
In your adapter add:
public interface OnItemClickListener {
void onItemClick(View view, int position, List<Task> mTaskList);
}
and
public OnItemClickListener mItemClickListener;
// Provide a suitable constructor (depends on the kind of dataset)
public TaskAdapter (List<Task> myDataset, OnItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
this.mDataset = mDataset;
}
plus the call in the ViewHolder class
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ViewHolder(View v) {
super(v);
...
closeBtn = (ImageView)v.findViewById(R.id.xImg);
closeBtn.setOnClickListener(this);
}
#Override
public void onClick(View v) {
// If not long clicked, pass last variable as false.
mItemClickListener.onItemClick(v, getAdapterPosition(), mDataset);
}
}
In your MainActivity change your adapter to handle the call
// set Adapter
mAdapter = new TaskAdapter(taskList, new TaskAdapter.OnItemClickListener() {
#Override
public void onItemClick(View v, int position) {
if (v.getId() == R.id.xImg) {
Task taskToDel = taskList.get(position);
// updating UI
taskList.remove(position);
thisAdapter.notifyItemRemoved(position);
// remove from db with unique id to use delete query
// dont use the position but something like taskToDel.getId()
taskToDel.delete();
}
}
});

Thanks to #yigit for his answer, his solution mainly worked, I just tweaked it a little bit so as to avoid using vh.getTask() which I was not sure how to implement.
final ViewHolder vh = new ViewHolder(customView);
final KittyAdapter final_copy_of_this = this;
// We attach a CheckChange Listener here instead of onBindViewHolder
// to avoid creating a listener object on each rebind
// Note Rebind is only called if animation must be called on view (for efficiency)
// It does not call on the removed if the last item is checked
vh.done.setChecked(false);
vh.done.setOnCheckedChangeListener(null);
vh.done.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
buttonView.setEnabled(false);
final int pos2 = vh.getAdapterPosition(); // THIS IS HOW TO GET THE UPDATED POSITION
// YOU MUST UPDATE THE DATABASE, removed by Title
DatabaseHandler db = new DatabaseHandler(mContext);
db.remove(mDataSet.get(pos2).getTitle(), fp);
db.close();
// Update UI
mDataSet.remove(pos2);
final_copy_of_this.notifyItemRemoved(pos2);
}
});
Notice instead to get the updated position, you can call vh.getAdapterPosition(), which is the line that will give you the updated position from the underlying dataset rather than the fake view.
This is working for me as of now, if someone knows of a drawback to using this please let me know. Hope this helps someone.

Personally, I don't like this concept of RecyclerViews. Seems like it wasn't thought of completely.
As it was said when removing an item the Recycler view just hides an item. But usually you don't want to leave that item in your collection. When deleting an item from the collection "it shifts its elements towards 0" whereas recyclerView keeps the same size.
If you are calling taskList.remove(position); your position must be evaluated again:
int position = recyclerView.getChildAdapterPosition(taskViewHolder.itemView);