I am trying to listen for row clicks (item clicks) on my recycler view from the Activity itself (not from adapter).
My Adapter so far looks like this:
public class ListMiestnostiAdapter extends RecyclerView.Adapter<ListMiestnostiAdapter.ViewHolder>{
private List<Miestnost> data;
// you provide access to all the views for a data item in a view holder
public static class ViewHolder extends RecyclerView.ViewHolder {
public ViewDataBinding binding;
public ViewHolder(ViewDataBinding binding) {
super(binding.getRoot());
this.binding = binding;
}
public void bind(Object obj){
binding.setVariable(BR.obj, obj);
binding.executePendingBindings();
}
}
public ListMiestnostiAdapter(List<Miestnost> data) {
this.data = data;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
ActivityListMiestnostiRowBinding itemBinding = ActivityListMiestnostiRowBinding.inflate(inflater, parent,false);
return new ViewHolder(itemBinding);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Miestnost item = data.get(position);
holder.bind(item);
}
#Override
public int getItemCount() {
return data.size();
}
}
And my row layout like this:
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="obj"
type="com.example.com.projectname.Models.Miestnost" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:attr/selectableItemBackground"
android:clickable="true"
android:focusable="true"
android:orientation="horizontal"
android:paddingBottom="#dimen/row_padding_vertical"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/row_padding_vertical">
<TextView
android:id="#+id/txt_miestnost_row_nazov"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="#{obj.Name}"
android:textSize="16dp" />
</LinearLayout>
</layout>
As I have already mentioned I am trying to listen to item clicks, but not from Adapter itself (as other posts suggested), but from my Activity which holds this RecyclerView.
Is such action even possible? If yes, then any help would be highly appreciated as I could not find anything on google.
You’ll first need an interface that specifies listener’s behavior. In this example, there is a sample model called ContentItem, so the click will return an item of that type:
public interface OnItemClickListener {
void onItemClick(ContentItem item);
}
The constructor will receive an object that implements this interface, along with the items to be rendered:
private final List<ContentItem> items;
private final OnItemClickListener listener;
public ContentAdapter(List<ContentItem> items, OnItemClickListener listener) {
this.items = items;
this.listener = listener;
}
You could alternatively create a setOnItemClickListener method and assign it that way. Now, in onBindViewHolder the ViewHolder will receive the constructor in the custom bind method:
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.bind(items.get(position), listener);
}
This is how this bind method looks:
public void bind(final ContentItem item, final OnItemClickListener listener) {
...
itemView.setOnClickListener(new View.OnClickListener() {
#Override public void onClick(View v) {
listener.onItemClick(item);
}
});
}
Use it whenever you need it by creating a new adapter and the listener that will implement the behavior when an item is clicked. A simple example:
recycler.setAdapter(new ContentAdapter(
items,
new ContentAdapter.OnItemClickListener() {
#Override
public void onItemClick(ContentItem item) {
Toast.makeText(getContext(), "Item Clicked", Toast.LENGTH_LONG).show();
}
}));
Source
To add to the answer provided by João Alvares Neto, we can call the OnItemClickListener directly from the layout.
In the variable tag, we can pass the OnItemClickListener and call it using the android:onClick property.
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="storyClickListener"
type="com.hoomanwe.zorro.ui.adapter.OnStoryClickListener" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="#{() -> storyClickListener.onStoryClick(item.id)}" />
</layout>
By this way, you can eliminate the following code from the solution provided by João Alvares Neto
public void bind(final ContentItem item, final OnItemClickListener listener) {
itemView.setOnClickListener(new View.OnClickListener() {
#Override public void onClick(View v) {
listener.onItemClick(item);
}
});
}
Related
I am creating Android app, using room database.
I have two tables DogsTable:
#PrimaryKey(autoGenerate = true)
int dog_id;
String dogName;
and CatsTable (both tables have constructor and getter methods ):
#PrimaryKey(autoGenerate = true)
int cat_id;
String catName;
1- How to display in one RecyclerView two different object type
ArrayList<DogsTable> dog_list;
ArrayList<CatsTable> cat_list;
I am getting the values of dog_list and cat_list from ViewModel Query as show in MainActivity.class.
2- How to fix getItemCount() method? I don't know how to return two different object cat_list.size(); and dog_list.size();
3- Also in onBindViewHolder() method I don`t know how to get cat_list values to display them in UI?
4- Another problem is in swapToDelete() Method in MainActivity.class, I can get the dog id to delete it, but I can not get the cat id to delete it, how can I get the cat id ?
5- How can I display (dog1,dog2 , dog3) as show in first image? (i inserted the value manually in the first image just to show how i want to display them )
Existing Output as below:
My code
MainActivity.java
public class MainActivity extends AppCompatActivity implements MainActivityAdapter.ItemClickListener {
MyViewModel viewModel;
MainActivityAdapter adapter;
RecyclerView recyclerView;
LinearLayoutManager layoutManager;
Button btn_addDog, btn_addCat;
EditText et_addDogName, et_addCatName;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
viewModel = ViewModelProviders.of(this).get(MyViewModel.class);
actionButton();
buildRecyclerView();
setUpViewModel_dogs();
swapToDelete_dog();
}
private void initViews() {
et_addDogName = findViewById(R.id.addDogNameET_xml);
et_addCatName = findViewById(R.id.addCatNameET_xml);
}
public void actionButton() {
btn_addDog = findViewById(R.id.AddDog_btn_xml);
btn_addCat = findViewById(R.id.AddCat_btn_xml);
btn_addDog.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
insertDog();
}
});
btn_addCat.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
insertCat();
}
});
}
private void buildRecyclerView() {
recyclerView = findViewById(R.id.recyclerView_id);
adapter = new MainActivityAdapter(this, this);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(adapter);
}
// Query
public void setUpViewModel_dogs() {
viewModel = ViewModelProviders.of(this).get(MyViewModel.class);
viewModel.getAllDogs().observe(this, new Observer<List<DogsTable>>() {
#Override
public void onChanged(#Nullable List<DogsTable> dogsTables) {
adapter.setDog_list((ArrayList<DogsTable>) dogsTables);
}
});
}
public void setUpViewModel_cats(){
viewModel.getAllCats().observe(this, new Observer<List<CatsTable>>() {
#Override
public void onChanged(#Nullable List<CatsTable> catsTables) {
adapter.setCat_list((ArrayList<CatsTable>) catsTables);
}
});
}
// Add
public void insertDog() {
String dogName = String.valueOf(et_addDogName.getText()).trim();
DogsTable obj_dog = new DogsTable(dogName);
viewModel.insertDog(obj_dog);
Toast.makeText(this, "Dog Added", Toast.LENGTH_SHORT).show();
}
public void insertCat() {
String catName = String.valueOf(et_addCatName.getText());
CatsTable obj_cat = new CatsTable(catName);
viewModel.insertCat(obj_cat);
Toast.makeText(this, "cat Added", Toast.LENGTH_SHORT).show();
}
// Delete
public void swapToDelete_dog() {
new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(final RecyclerView.ViewHolder viewHolder, int direction) {
List<DogsTable> dog_pos = adapter.getDog_list();
viewModel.deleteDog(dog_pos.get(viewHolder.getAdapterPosition()));
}
}
).attachToRecyclerView(recyclerView);
}
public void swapToDelete_cat() {
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int item_id = item.getItemId();
if (item_id == R.id.menu_add) {
Intent in = new Intent(this, Add.class);
startActivity(in);
}
return super.onOptionsItemSelected(item);
}
#Override
public void onItemClickListener(int pet_id) {
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/addDogNameET_xml"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:hint="add Dog name" />
<Button
android:id="#+id/AddDog_btn_xml"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="add" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="#+id/addCatNameET_xml"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
android:hint="add Cat name" />
<Button
android:id="#+id/AddCat_btn_xml"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="add" />
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView_id"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:ignore="MissingConstraints" />
</LinearLayout>
MainActivityAdapter.java
public class MainActivityAdapter extends RecyclerView.Adapter<MainActivityAdapter.MyViewHolder> {
Context mContext;
ArrayList<DogsTable> dog_list;
ArrayList<CatsTable> cat_list;
ItemClickListener mItemClickListener;
public MainActivityAdapter(Context context , ItemClickListener itemClickListener) {
this.mContext = context;
this.mItemClickListener = itemClickListener;
}
public interface ItemClickListener {
void onItemClickListener(int pet_id);
}
#NonNull
#Override
public MyViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(mContext).inflate(R.layout.activity_main_adapter, viewGroup, false);
return new MyViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull MyViewHolder holder, int position) {
DogsTable dog_pos = dog_list.get(position);
// CatsTable catsTable = cat_list.get(position);
holder.dogName.setText(String.valueOf(dog_pos.getDogName()));
// holder.catName.setText(String.valueOf(catsTable.getCatName()));
}
#Override
public int getItemCount() {
if (dog_list == null ) {
return 0;
} else {
return dog_list.size();
}
}
public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener , ItemClickListener {
TextView dogName;
TextView catName;
public MyViewHolder(#NonNull View itemView) {
super(itemView);
dogName = itemView.findViewById(R.id.dogName_xml);
catName = itemView.findViewById(R.id.catName_xml);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
int pet_id = dog_list.get(getAdapterPosition()).getDogs_id();
mItemClickListener.onItemClickListener(pet_id);
}
#Override
public void onItemClickListener(int pet_id) {
int pos = dog_list.get(getAdapterPosition()).getDogs_id();
mItemClickListener.onItemClickListener(pet_id);
}
}
public void setDog_list(ArrayList<DogsTable> dog_list) {
this.dog_list = dog_list;
notifyDataSetChanged();
}
public ArrayList<DogsTable> getDog_list() {
return dog_list;
}
public void setCat_list(ArrayList<CatsTable> cat_list) {
this.cat_list = cat_list;
}
}
activity_main_adapter.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Dogs: " />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/dogName_xml"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Cats: " />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp">
<TextView
android:id="#+id/catName_xml"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</LinearLayout>
To support different view types, RecyclerView.Adapter provides a useful method int getItemViewType(int position):
Return the view type of the item at position for the purposes of view recycling.
The default implementation of this method returns 0, making the assumption of a single view type for the adapter. Unlike ListView adapters, types need not be contiguous. Consider using id resources to uniquely identify item view types.
Then, in onCreateViewHolder you can see that a second parameter is int viewType which comes from the method int getItemViewType(int position). Based on that, you can instantiate a ViewHolder you need, e.g. DogViewHolder or CatViewHolder.
But what about storing multiple view models in a single adapter and defining which ViewHolder type should be actually instantiated? Here are two most popular approaches:
Declaring multiple containers for multiple types and defining a custom logic for getItemViewType method, e.g. all odd numbers will go in the dogs' list and even numbers will go in the cats' list (or any other method, but beware that you will have to cope with different lists' sizes and all the view types you need). Also, getItemsCount should be overriden appropriately (return list1.size() + list2.size + ... + listN.size();)
Put all the view models in a single list and perform some kind of attributes checks: either it will be some property or the type itself (not recommended for scalability reasons). Then your code will look like this:
public int getItemViewType(int position) {
CommonParentForUpcasting item = items.get(position);
if (item instanceOf Dog) { // or something like item.type == Animal.CAT
return R.id.holder_dog;
} else {
return R.id.holder_cat;
}
}
If you want to come up with a second solution, this solution should suit you well.
Also, make sure to check this StackOverflow answer.
Ok I'll try one more time. Last time I asked about passing data between recyclerview and item and one person helped me with open item by click, but I still don't have idea how to show the data of clicked item in new activity. I want to click on an item and then display the data of that item in new activity. In this activity I want to edit data.
Does anyone knows how to do it? I need any idea.
RecyclerView Adapter with OnItemClickListener interface:
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.TaskViewHolder> {
private List<MainViewModel> mTasks;
private List<Task> tasks = new ArrayList<>();
private Context context;
private EditTaskViewModel editTaskViewModel;
public RecyclerViewAdapter(List<MainViewModel> tasks, Context context, EditTaskViewModel editTaskViewModel) {
this.mTasks = tasks;
this.context = context;
this.editTaskViewModel = editTaskViewModel;
}
#NonNull
#Override
public RecyclerViewAdapter.TaskViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
final RecyclerViewItemBinding binding = DataBindingUtil.inflate(inflater, R.layout.recycler_view_item, parent, false);
binding.setItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(View view) {
Intent intent = new Intent(view.getContext(), EditTaskActivity.class);
intent.putExtra("id", binding.getPosition());
view.getContext().startActivity(intent);
Toast.makeText(view.getContext(), "ID " + binding.getPosition(), Toast.LENGTH_SHORT).show();
}
});
return new TaskViewHolder(binding);
}
#Override
public void onBindViewHolder(#NonNull final RecyclerViewAdapter.TaskViewHolder holder, final int position) {
Task currentTask = tasks.get(position);
holder.mBinding.descriptionItem.setText(currentTask.getDescription());
holder.mBinding.dateItem.setText(currentTask.getDate());
holder.mBinding.timeItem.setText(currentTask.getTime());
holder.mBinding.setPosition(position);
}
#Override
public int getItemCount() {
return tasks.size();
}
public void setTasks(List<Task> tasks) {
this.tasks = tasks;
notifyDataSetChanged();
}
public Task getTaskPosition(int position) {
return tasks.get(position);
}
public class TaskViewHolder extends RecyclerView.ViewHolder {
private final RecyclerViewItemBinding mBinding;
public TaskViewHolder(RecyclerViewItemBinding binding) {
super(binding.getRoot());
this.mBinding = binding;
}
public void bind (MainViewModel mainViewModel){
mBinding.setItemView(mainViewModel);
mBinding.executePendingBindings();
}
}
public interface OnItemClickListener {
void onItemClick(View view);
}
Item XML file:
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="itemView"
type="com.example.daniellachacz.taskmvvm.viewmodel.MainViewModel">
</variable>
<variable
name="itemClickListener"
type="com.example.daniellachacz.taskmvvm.adapter.RecyclerViewAdapter.OnItemClickListener">
</variable>
<variable
name="task"
type="com.example.daniellachacz.taskmvvm.model.Task">
</variable>
<variable
name="position"
type="int">
</variable>
</data>
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="120dp"
android:shadowColor="#color/colorPrimary"
android:backgroundTint="#color/cardview_shadow_end_color">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="110dp"
android:layout_marginBottom="6dp"
android:layout_marginTop="6dp"
android:layout_marginStart="6dp"
android:layout_marginEnd="6dp"
android:onClick="#{(view)-> itemClickListener.onItemClick(view)}">
<TextView
android:id="#+id/description_item"
android:layout_width="250dp"
android:layout_height="96dp"
android:layout_marginStart="5dp"
android:layout_marginTop="9dp"
android:layout_marginBottom="5dp"
android:text="#{itemView.description}"
android:textSize="18sp"
android:textColor="#020202"
android:focusable="true" />
<TextView
android:id="#+id/date_item"
android:layout_width="90dp"
android:layout_height="40dp"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="9dp"
android:layout_marginEnd="10dp"
android:gravity="center"
android:text="#{itemView.date}"
android:textColor="#020202"
android:textSize="16sp" />
<TextView
android:id="#+id/time_item"
android:layout_width="90dp"
android:layout_height="40dp"
android:layout_alignParentBottom="true"
android:layout_alignStart="#+id/date_item"
android:layout_marginBottom="10dp"
android:layout_marginEnd="10dp"
android:gravity="center"
android:text="#{itemView.time}"
android:textColor="#020202"
android:textSize="16sp" />
</RelativeLayout>
</android.support.v7.widget.CardView>
</layout>
onCreate:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
floatingActionButton = findViewById(R.id.floating_action_button);
List<Task> tasks = new ArrayList<>();
RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setHasFixedSize(true);
final RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(context, tasks);
recyclerView.setAdapter(recyclerViewAdapter);
mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class);
mainViewModel.getAllTasks().observe(this, recyclerViewAdapter::setTasks);
Here are a couple of suggestions you might find useful:
Don't depend on ViewModels in your adapters. ViewModels are meant to handle events from views (Fragments or Activities) and broadcast updates back to the views via some observable mechanism (most commonly LiveData instances). Referencing your ViewModels directly inside an adapter is bad, since it couples them together. This means that it will be very hard for you to reuse your adapter with a different ViewModel if needed. I know it doesn't seem likely at this point in time, but just trust me on this one. After the changes have been applied, your adapter should look something like this:
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.TaskViewHolder> {
private LayoutInflater mLayoutInflater;
private List<Task> mTasks;
private OnItemClickListener mOnItemClickListener;
public RecyclerViewAdapter(#NonNull Context context, #NonNull List<Task> tasks) {
mLayoutInflater = LayoutInflater.fromContext(context);
mTasks = tasks;
}
public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
mOnItemClickListener = onItemClickListener;
}
#NonNull
#Override
public RecyclerViewAdapter.TaskViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
final RecyclerViewItemBinding binding = DataBindingUtil.inflate(mLayoutInflater, R.layout.recycler_view_item, parent, false);
return new TaskViewHolder(binding);
}
#Override
public void onBindViewHolder(#NonNull final RecyclerViewAdapter.TaskViewHolder holder, final int position) {
Task currentTask = tasks.get(position);
holder.bind(currentTask, mOnItemClickListener);
}
#Override
public int getItemCount() {
return tasks.size();
}
public void setTasks(List<Task> tasks) {
this.tasks = tasks;
notifyDataSetChanged();
}
public Task getTaskPosition(int position) {
return tasks.get(position);
}
public class TaskViewHolder extends RecyclerView.ViewHolder {
private final RecyclerViewItemBinding mBinding;
public TaskViewHolder(RecyclerViewItemBinding binding) {
super(binding.getRoot());
this.mBinding = binding;
}
public void bind (Task item, OnItemClickListener onItemClickListener) {
mBinding.setItem(item);
mBinding.executePendingBindings();
itemView.setOnClickListener(view -> {
if (onItemClickListener != null) {
onItemClickListener.onItemClick(view, item);
}
}
}
}
public interface OnItemClickListener {
void onItemClick(View view, Task item);
}
}
The OnItemClickListener.onItemClick() method now passes the view and the item itself as parameters. This is the easiest way to expose the clicked item to whoever might be interested. The on click listener is now set at the adapter level, using setOnItemClickListener().
The setting of the OnClickListener of the item view is now done in the bind() method of the TaskViewHolder. When binding, we know the exact item that is going to populate the view, so we can return it to the OnItemClickListener.
You have to simplify the layout as well, since there are a lot of things that are not really needed. It may look like this:
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="task"
type="com.example.daniellachacz.taskmvvm.model.Task">
</variable>
</data>
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="120dp"
android:shadowColor="#color/colorPrimary"
android:backgroundTint="#color/cardview_shadow_end_color">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="110dp"
android:layout_marginBottom="6dp"
android:layout_marginTop="6dp"
android:layout_marginStart="6dp"
android:layout_marginEnd="6dp">
<TextView
android:id="#+id/description_item"
android:layout_width="250dp"
android:layout_height="96dp"
android:layout_marginStart="5dp"
android:layout_marginTop="9dp"
android:layout_marginBottom="5dp"
android:text="#{item.description}"
android:textSize="18sp"
android:textColor="#020202"
android:focusable="true" />
<TextView
android:id="#+id/date_item"
android:layout_width="90dp"
android:layout_height="40dp"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="9dp"
android:layout_marginEnd="10dp"
android:gravity="center"
android:text="#{item.date}"
android:textColor="#020202"
android:textSize="16sp" />
<TextView
android:id="#+id/time_item"
android:layout_width="90dp"
android:layout_height="40dp"
android:layout_alignParentBottom="true"
android:layout_alignStart="#+id/date_item"
android:layout_marginBottom="10dp"
android:layout_marginEnd="10dp"
android:gravity="center"
android:text="#{item.time}"
android:textColor="#020202"
android:textSize="16sp" />
</RelativeLayout>
</android.support.v7.widget.CardView>
</layout>
The only variable is the item and we are binding it's properties to the TextViews.
I guess this should be enough to get you going.
Just a couple of other things that are not directly related to the question, but are important.
Null safety - you never check the input when calling setTask() in the adapter. A client may pass null and cause crashes all over the place. You should try and prevent that.
Calling notifyDataSetChanged() is not a good practice when working with RecyclerView.Adapter since this will cancel all the built-in animations of the RecyclerView. It's better to use the other notify... methods. You might want to check DiffUtil at some point.
It depends on how your data is stored and if it accessible in the second activity. If you have a static ArrayList of your data you can pull the data from it using the index you passed in your onclick of the RV item. For example:
class myData{
private ArrayList<Data> myDataArray;
static ArrayList<Data> getMyDataArray(){
return myDataArray;
}
static void setMyDataArray(array)
myDataArray = array;
}
So you fill your RV with getMyDataArray() then you set the onlclick to send the index clicked in the RV to the next activity.
In onLoad of the second activity:
int myDataIndex = getIntent().getIntExtra("id",0);
Data myData = myData.getMyDataArray().get(myDataIndex);
Note: Data is whatever your data is, could be strings, or ints, or a custom class/object with data.
Here is what I have done for item click listener in recycler view using data binding.
ADAPTER CODE
public class TC_DashboardRecViewAdapter extends RecyclerView.Adapter<TC_DashboardRecViewAdapter.ViewHolder> {
Context context;
List<String> list;
private TcDashboardItemBinding tcDashboardItemBinding;
ItemClickListener itemClickListener;
public TC_DashboardRecViewAdapter(Context context, List<String> dashboardItems, ItemClickListener itemClickListener) {
this.context = context;
this.list = dashboardItems;
this.itemClickListener = itemClickListener;
}
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
ViewDataBinding binding = DataBindingUtil.inflate(inflater, R.layout.tc_dashboard_item, parent, false);
tcDashboardItemBinding = (TcDashboardItemBinding) parent.getTag();
return new ViewHolder(binding);
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
holder.bind(list.get(position), itemClickListener, position);
}
#Override
public int getItemCount() {
return list.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
private ViewDataBinding binding;
public ViewHolder(ViewDataBinding binding) {
super(binding.getRoot());
this.binding = binding;
}
public void bind(String s, ItemClickListener itemClickListener, int position) {
this.binding.setVariable(BR.itemModel, s);
this.binding.executePendingBindings();
binding.getRoot().setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(itemClickListener !=null){
itemClickListener.onItemClicked(binding.getRoot(), s, position);
}
}
});
}
}
ITEM CLICK INTERFACE:
public interface ItemClickListener {
void onItemClicked(View vh, Object item, int pos);
}
FRAGMENT/ACTIVITY CODE:
public class TC_DashboardFragment extends BaseFragment implements ItemClickListener {
public void onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
tc_dashboardRecViewAdapter = new TC_DashboardRecViewAdapter(getContext(), getDashboardItems(), this);
linearLayoutManager = new LinearLayoutManager(getContext());
dashboardrecyclerview.setLayoutManager(new LinearLayoutManager(getContext()));
binding.setAdapter(tc_dashboardRecViewAdapter);
}
#Override
public void onItemClicked(View vh, Object item, int pos) {
Toast.makeText(mainActivity, item.toString(), Toast.LENGTH_SHORT).show();
}
When you run the code and click on recycler view item it would show a toast with the text from the item clicked.
I have a simple RecyclerView with only a TextView as each item. By using recyclerView.smoothScrollToPosition(myPosition); in MainActivity, I can scroll to custom item. What I need is changing textColor for current item that is scrolled to, just after scrolling.
For example, if myPosition is 3 and 3rd item of RecyclerView is "current" or "focused", I want to change textColor for this 3rd item.
How can I do that?
MainActivity.java:
public class MainActivity extends AppCompatActivity implements MyAdapter.ItemClickListener {
MyAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<String> itemTitle_List = new ArrayList<>();
itemTitle_List.add("facebook");
itemTitle_List.add("flickr");
itemTitle_List.add("google_plus");
itemTitle_List.add("instagram");
itemTitle_List.add("linkedin");
itemTitle_List.add("pinterest");
itemTitle_List.add("soundcloud");
itemTitle_List.add("swarm");
itemTitle_List.add("tumblr");
itemTitle_List.add("twitter");
// set up the RecyclerView
RecyclerView recyclerView = findViewById(R.id.recycler_view);
RecyclerView.LayoutManager layoutManager=new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
adapter = new MyAdapter(this, itemTitle_List);
adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
recyclerView.smoothScrollToPosition(3);
}
#Override
public void onItemClick(View view, int position) {
//Toast.makeText(this, "You clicked " + adapter.getItem(position) + " on row number " + position, Toast.LENGTH_SHORT).show();
}
}
MyAdapter.java:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private List<String> itemTitle_List;
private LayoutInflater layoutInflater;
private ItemClickListener itemClickListener;
// data is passed into the constructor
MyAdapter(Context context, List<String> itemTitle_List) {
this.layoutInflater = LayoutInflater.from(context);
this.itemTitle_List = itemTitle_List;
}
// inflates the row layout from xml when needed
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = layoutInflater.inflate(R.layout.recyclerview_row, parent, false);
return new ViewHolder(view);
}
// total number of rows
#Override
public int getItemCount() {
return itemTitle_List.size();
}
// binds the title to the TextView, and image to the ImageView in each row
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
String title = itemTitle_List.get(position);
holder.textView.setText(title);
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView textView;
ViewHolder(View itemView) {
super(itemView);
textView = itemView.findViewById(R.id.text_view);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
if (itemClickListener != null) itemClickListener.onItemClick(view, getAdapterPosition());
}
}
// convenience method for getting data at click position
String getItem(int id) {
return itemTitle_List.get(id);
}
// allows clicks events to be caught
void setClickListener(ItemClickListener itemClickListener) {
this.itemClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
}
activity_main.xml:
<?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.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/recycler_view">
</android.support.v7.widget.RecyclerView>
</RelativeLayout>
recyclerview_row.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal"
android:padding="10dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/text_view"
android:layout_gravity="center_vertical"
android:layout_margin="10dp"/>
</LinearLayout>
I found a simple solution, but I'm not sure if this is standard or not.
Add a public integer, named row_index=0 and a public function, in MyAdapter.java, as below:
public void selectRow(int index){
row_index=index;
notifyDataSetChanged();
}
And in the onBindViewHolder function in MyAdapter.java, add this code:
if(position==row_index){
holder.textView.setTextColor(Color.RED);
}
else{
holder.textView.setTextColor(Color.BLACK);
}
Then, after recyclerView.smoothScrollToPosition(3) in MainActivity.java, use this:
MyAdapter.selectRow(3);
MyAdapter.notifyDataSetChanged();
This way, when RecyclerView scrolled to 3rd item, the textColor for this item changes to Red.
In my android app I have one activity to show a RecyclerView in which each row is composed by a TextView and 2 buttons. Just like that:
Well, following many explanations of internet I have made this Adapter:
public class ListAdapter extends
RecyclerView.Adapter<ListAdapter.ViewHolder> {
private LayoutInflater layoutInflater;
protected Vector<List> lists;
public ListAdapter(Context context, Vector lists) {
layoutInflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.lists = lists;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = layoutInflater.inflate(R.layout.listadapter, null);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
List list = lists.elementAt(position);
holder.name.setText(list.getName());
//holder.delete.set HOW DO I GET BUTTON HERE?
}
#Override
public int getItemCount() {
return lists.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder
implements View.OnClickListener {
public TextView name;
public Button edit;
public Button delete;
public ViewHolder(View itemView) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.listname);
edit = (Button) itemView.findViewById(R.id.edit);
delete = (Button) itemView.findViewById(R.id.delete);
edit.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.edit:
break;
case R.id.delete:
break;
default:
break;
}
}
}
}
I haven't found examples of having 2 buttons (there are only examples of adding images) in each view of the recyclerview, as in the first image. I mean, guess I have 10 List elements in my RecyclerView, how can I have in each of them to one side a TextView with the name of the List and 2 buttons and handle clickListener?. As in the following image, which I have done by hand for you to see what I am talking about:
This is the activity that will show the recyclerView; don't take it into account because I am pretty sure the way is wrong. I get lists information from sqlite database:
public class ShowListOfLists extends AppCompatActivity {
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_list_of_lists);
LocalDB localDB = new LocalDB(this, "localBD", null, 1);
Vector <List> ListAdapter = localDB.getAllPrivateList();
recyclerView = (RecyclerView) findViewById(R.id.recyclerviewlistas);
recyclerView.setAdapter(new ListAdapter(this, ListAdapter));
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
}
A list have the following attributes:
-idList int
-name String
-Description String
-creationDate Date
-active int (0 or 1)
-deactivationDate Date
Thank you in advance.
/*******************************EDIT****************************************/
Thank to you I have been able to show the recyclerView and it works well. But I see that:
Instead of that:
This the XML code and design of the adapter:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="60dp"
android:background="#drawable/rectangle_bg"
android:orientation="horizontal"
android:weightSum="1"
android:layout_marginTop="5dp">
<TextView
android:id="#+id/listname"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:layout_weight="0.75"
android:gravity="center_vertical"
android:text="TextView"
android:textSize="15sp"/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="end"
android:orientation="vertical">
<ImageButton
android:id="#+id/delete"
android:layout_width="match_parent"
android:layout_height="30dp"
android:background="#android:color/transparent"
android:contentDescription="Delete"
app:srcCompat="#android:drawable/ic_menu_delete" />
<ImageButton
android:id="#+id/edit"
android:layout_width="match_parent"
android:layout_height="30dp"
android:background="#android:color/transparent"
android:contentDescription="Edit"
app:srcCompat="#android:drawable/ic_menu_edit" />
</LinearLayout>
</LinearLayout>
And this is the XML of the recyclerview
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="match_parent"
tools:context="com.pc.kanayel.runoutof.ShowListOfLists"
android:orientation="vertical"
android:id="#+id/recyclerviewlistas">
</android.support.v7.widget.RecyclerView>
You just need to add some code to your ListAdapter. It is there, where you have to implement onClickListener. The code for your case should look something like the one below.
You can pass any parameter you need to. It depends on the functionality you want to achieve. Here I have demonstrated passing the order of item clicked inside of list.
Option 1 (power/performance efficient)
So, what does the code below actually mean? You have already created a ViewHolder and implemented OnClickListener. That is correct. Now you need to set OnClickListener to two buttons. But what these buttons will do when clicked is defined by the interface we created inside of ViewHolder.
When app will run RecyclerView will create as many ViewHolders as it is needs to fill the available screen with list items by calling onCreateViewHolder() method for each of viewholders. When you scroll up/down these ViewHolders will be reused. OnCreateViewHolder() is not called, only onBindViewHolder() is called to update the content of viewholder. The code below made so that, when ViewHolder is created it will also create an MyClickListener that will be used by OnClickListener of viewholder and when viewholder is reused it will not create new OnClickListener. It means that our method is performance efficient.
Option 2 (not efficient)
You could also setOnClickListener() inside of onBindViewHolder(). However, as I have mentioned in the paragraph above, this method is called every time you scroll to update the content of viewholder. Now it would create new OnClickListener object everytime. While Option 1 has OnClickListener on every ViewHolder and it reuses them.
Code for Option 1
public class ListAdapter extends RecyclerView.Adapter<ListAdapter.ViewHolder> {
private LayoutInflater layoutInflater;
protected Vector<List> lists;
public ListAdapter(Context context, Vector lists) {
layoutInflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.lists = lists;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = layoutInflater.inflate(R.layout.listadapter, null);
ViewHolder holder = new ViewHolder(view, new MyClickListener() {
#Override
public void onEdit(int p) {
// Implement your functionality for onEdit here
}
#Override
public void onDelete(int p) {
// Implement your functionality for onDelete here
}
});
return holder;
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
List list = lists.elementAt(position);
holder.name.setText(list.getName());
}
#Override
public int getItemCount() {
return lists.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
MyClickListener listener;
TextView name;
Button edit;
Button delete;
public ViewHolder(View itemView, MyClickListener listener) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.listname);
edit = (Button) itemView.findViewById(R.id.edit);
delete = (Button) itemView.findViewById(R.id.delete);
this.listener = listener;
edit.setOnClickListener(this);
delete.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.edit:
listener.onEdit(this.getLayoutPosition());
break;
case R.id.delete:
listener.onDelete(this.getLayoutPosition());
break;
default:
break;
}
}
}
public interface MyClickListener {
void onEdit(int p);
void onDelete(int p);
}
}
Edit for your second question
To make list items take all the width set the width of your recyclerview to match_parent. It is also better to make it a child view of some layout. For instance as given below.
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.pc.kanayel.runoutof.ShowListOfLists">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerviewlistas"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<RelativeLayout>
And change this code inside of your adapter:
View view = layoutInflater.inflate(R.layout.listadapter, null);
to this:
View view = layoutInflater.inflate(R.layout.listadapter, parent, false);
You can do simply like this:
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
List list = lists.elementAt(position);
holder.name.setText(list.getName());
holder.edit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Do your stuff
}
});
holder.delete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Do your stuff
}
});
}
I need to access a method of RecyclerView Adapter from View Holder. I don't find any solution for this.
Or is it possible to access adpater'method(get an instance of adapter) from ViewModel class (I've defined a viewModel for items of RecyclerView in MVVM pattern) of ViewHolder.
Regards,
Habib
Thanks to all, here is code snippets. in ItemViewModel class I want to get adapter's methods.
Adapter && ViewHolder :
public class MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder> {
public class MyViewHolder extends RecyclerView.ViewHolder {
........
public MyViewHolder(View view) {
super(view);
......
}
}
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item, parent, false);
return itemView;
}
#Override
public void onBindViewHolder(MyViewHolder holder, int position) {
........
}
#Override
public int getItemCount() {
.........
}
}
list_item.xml :
<?xml version="1.0" encoding="utf-8"?>
<data>
<variable
name="viewModel"
type="program.viewmodel.ItemViewModel" />
</data>
<android.support.v7.widget.CardView
android:id="#+id/cvMain"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="#{viewModel.onClickCard()}"
android:onLongClick="#{viewModel.onLongClickCard()}" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:paddingLeft="5dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/engM"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:paddingLeft="5dp"
android:text="#{viewModel.engligh}"
android:textSize="20sp" />
</LinearLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
ItemViewModel class :
public class ItemViewModel{
private Proverb proverb; //Proverb is model class
public ItemViewModel(Proverb item) {
this.proverb = item;
notifyChange();
}
#Bindable
public String getEngligh() {
return proverb.getEngligh();
}
/**
* click each item
* #return
*/
public View.OnClickListener onClickProverb() {
return new View.OnClickListener() {
#Override
public void onClick(View view) {
// here I need to access adapter's method
}
};
}
/**
* long click listener
* #return
*/
public View.OnLongClickListener onLongClickProverb() {
return new View.OnLongClickListener() {
#Override
public boolean onLongClick(View view) {
// here I need to access adapter's method
return true;
}
};
}
}