I create a RecyclerView with CardViews in my app. Now I want to add inside each CardView a new List of custom Views, with a custom layout (see example Image). When the add button is pressed, there should be insert a new row of this layout inside the card.
How do I realize that? In the internet I readed, that a ListView inside the CardView is not possible, because a ListView is scrollable, and there should not be two scrollable Views on the activity (thats what I found..)
the red marked row is the custom row.
for the RecylcerView I used the ViewHolder, CustomAdapter, etc.
Do I need this for the rows inside to? or is there a simpler way?
What I would do is attached a click handler to the Views is your ViewHolder. In this event handler you can delegate to a presenter of some sort that will add/remove/edit the View in the card holder.
private class MyHolder extends ViewHolder
implements View.OnClickListener {
...
public MyHolder(View itemView, MyPresenter presenter) {
super(itemView);
itemView.setOnClickListener(this);
...
}
#Override
public void onClick(View v) {
presenter.addRow(v);
}
}
Related
I have an activity which contain a recycler view, in this activity is implemented the edit mode like a lot of applications. everythings works well but I have some performance issue and i'am tryng to goes more deep in the pest practices.
User goes in edit mode by select a menuItem in the toolbar which is placed in the activity, so in the menuItemClickListener in the activity I call a method of the adapter which is used to tell him that user want to go in edit mode:
mAdapter.setEditMode(true);
then in the adapter:
public void setEditMode(boolean editMode){
this.editMode = editMode;
notifyDataSetChanged(); //in order to change the items layout
}
Now the most difficult part: I need to change the itemClickListener when the editMode variable is set to true, so the listener associated with the holder's itemView change dinamically. I am doing this think in onBindViewHolder so I can set the right listener when the edit mode variable change.
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder,int position) {
if(editMode){
holder.itemView.setOnClickListener(listener1);
}
else{
holder.itemView.setOnClickListener(listener2);
}
}
this solution works but I know that placing a listener inside onBindViewHolder method is a bad practice so I would like to find a solution that allows to implement the listener in the viewHolder constructor.
This is not simple because when the editMode variable is changing the viewHolder constructor is not being called, so he can't set the right listener.
are there any best practice to do this?
After scouring various StackOverFlow answers regarding the most optimum location for a clickListener, people seem to be divided across multiple implementations. Here is what I know for adding a listener in the ViewHolder.
1. Adapter:
In your Adapter, override the onCreateViewHolder() method
#Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View view = LayoutInflater.from(//pass in your args);
ImageView imageview1 = //init your views
TextView textView = //init your views
return new MyViewHolder(view, textView);
}
2. Viewholder:
When you create your Viewholder class, allow it to implement View.OnClickListener and override the onClick method there.
public static class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ImageView imageView1;
private MyViewHolder(View itemView, ImageView imageView) {
super(itemView);
itemView.setOnClickListener(this);
imageView1 = imageView;
}
#Override
public void onClick(View view) {
//Implement your click functionality here
}
}
I had made a navigation drawer which is having header footer and list. I wonder how to apply touch event in specific navigation drawer header image and footer. I'm having navigation drawer with Header which contain Image and name of the user then in between list of items and then footer.
All the xml file(Header, CustomRow and footer) are in recyclerView,
so i want basically functionality to click header image,customrom and
footer as well.
If you are using recyclerview you must have ViewHolder as well. Yes? Your problem is fixed.
You can define clickListeners within ViewHolder
Taking an example -
class AddedProductHolder extends RecyclerView.ViewHolder {
View mCardContainer;
AddedProductHolder(View itemView) {
super(itemView);
mContainer = itemView.findViewById(R.id.conatiner);
// Define clickListener here...
mCardContainer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// Do your stuff.. If you need position of item clicked.. user getAdapterPosition()
}
});
}
}
It is my third day now dealing with the handling of my view clicks. I originally was using ListView, then I switched to RecyclerView. I have added android:onclick elements to every control on my row_layout and I am handling them in my MainActivity like this:
public void MyMethod(View view) {}
In my old ListView implementation, I have done setTag(position) to be able to get it in MyMethod by doing this inside it:
Integer.parseInt(view.getTag().toString())
This worked nicely without problems. Though now I am dealing with RecyclerView and being forced to use the ViewHolder, which does not offer a setTag method. After searching for 2 hours, I have found that people use setTag like this:
holder.itemView.setTag(position)
This was acceptable. Though when I try to get the value from the MyMethod function using the line:
Integer.parseInt(view.getTag().toString())
The application crashes. I have read several implementation of onclick handling inside the adapter which works but I have to use the MainActivity because I am using something that is unique to that activity.
TL;DR I want to send the position of the clicked row to my MainActivity in a simple manner.
Edit: I apologize for the confusion since my topic was not very thorough. I have a RecyclerView and an adapter. The adapter is linked to my row_layout. This row_layout xml has one root LinearLayout. Inside it there is one TextView, another LinearLayout (which has two TextViews) and one Button (for simplicity). I do not want to suffer for dealing with the clicks on RecylerView like I did with the ListView. So, I have decided to add an android:onclick for every control, then link TextView and LinearLayout to a single method and link the Button (and future Buttons) to their unique methods. What I am missing is that I want to be able to tell the position on each of the receiving methods on my MainActivity. If I must link everything that comes from the adapter and goes into the MainActivity to a single onclick handler, so be it. Although, how would I tell which control fired the click?
Edit 2: The requested layout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:onClick="MyMethod"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="1">
<TextView
android:id="#+id/letter"
android:onClick="MyMethod"
android:layout_width="60dp"
android:layout_height="fill_parent"
/>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:onClick="MyMethod"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/firstname"
android:onClick="MyMethod"
android:layout_width="fill_parent"
android:layout_height="17dp" />
<TextView
android:id="#+id/longname"
android:onClick="MyMethod"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
<Button
android:text="Test"
android:onClick="OtherMethod"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:id="#+id/process"/>
</LinearLayout>
You can achieve this by creating an interface inside your adapter for an itemclicklistener and then you can set onItemClickListener from your MainActivity.
Somewhere inside your RecyclerViewAdapter you would need the following:
private onRecyclerViewItemClickListener mItemClickListener;
public void setOnItemClickListener(onRecyclerViewItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
}
public interface onRecyclerViewItemClickListener {
void onItemClickListener(View view, int position);
}
Then inside your ViewHolder (which I've added as an inner class inside my adapter), you would apply the listener to the components you'd like the user to click, like so:
class RecyclerViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ImageView imageview;
RecyclerViewHolder(View view) {
super(view);
this.imageview = (ImageView) view
.findViewById(R.id.image);
imageview.setOnClickListener(this);
}
#Override
public void onClick(View v) {
if (mItemClickListener != null) {
mItemClickListener.onItemClickListener(v, getAdapterPosition());
}
}
}
This example shows an onClickListener being applied to the image inside a ViewHolder.
recyclerView.setAdapter(adapter);// set adapter on recyclerview
adapter.notifyDataSetChanged();// Notify the adapter
adapter.setOnItemClickListener(new RecyclerViewAdapter.onRecyclerViewItemClickListener() {
#Override
public void onItemClickListener(View view, int position) {
//perform click logic here (position is passed)
}
});
To implement this code, you would setOnItemClickListener to your adapter inside MainActivity as shown above.
EDIT
Because the View is getting passed into the OnItemClickListener, you can perform a switch statement inside the listener to ensure that the right logic is being performed to the right component. All you would need to do is take the logic from the MyMethod function and copy and paste it to the component you wish it to be applied to.
Example:
recyclerView.setAdapter(adapter);// set adapter on recyclerview
adapter.notifyDataSetChanged();// Notify the adapter
adapter.setOnItemClickListener(new RecyclerViewAdapter.onRecyclerViewItemClickListener() {
#Override
public void onItemClickListener(View view, int position) {
Switch (view.getId()) {
case R.id.letter:
//logic for TextView with ID Letter here
break;
case R.id.firstname:
//logic for TextView with ID firstname here
break;
....
//the same can be applied to other components in Row_Layout.xml
}
}
});
You would also need to change something inside the ViewHolder. instead of applying the OnClickListener to an ImageView, you would need to apply to the whole row like so:
RecyclerViewHolder(View view) {
super(view);
this.imageview = (ImageView) view
.findViewById(R.id.image);
view.setOnClickListener(this);
}
EDIT 2
Explanation:
So, with every RecyclerView. You need three components, The RecyclerView, RecyclerViewAdapter and the RecyclerViewHolder. These are what define the actual components the user sees (RecyclerView) and the Items within that View. The Adapter is where everything is pieced together and the Logic is implemented. The ins and outs of these components are nicely explained by Bill Phillips with the article RecyclerView Part 1: Fundamentals For ListView Experts over at Big Nerd Ranch.
But to further explain the logic behind the click events, it's basically utilizing an interface to pass information from the RecyclerViewAdapter to the RecyclerViewHolder to your MainActivity. So if you follow the life-cycle of the RecyclerView adapter, it'll make sense.
The adapter is initialized inside your MainActivity, the adapter's constructor would then be called with the information being passed. The components would then be passed into the adapter via the OnCreateViewHolder method. This itself tells the adapter, that's how you would like the list to look like. The components in that layout, would then need to be individually initialized, that's where the ViewHolder comes into play. As you can see like any other components you would initialize in your Activities, you do the same in the ViewHolder but because the RecyclerViewAdapter inflates the ViewHolder you can happily use them within your adapter as shown by Zeeshan Shabbir. But, for this example you would like multiple components to have various logic applied to each individual one in your MainActivity class.
That's where we create the click listener as a global variable (so it can be accessed by both the ViewHolder and the Adapter) the adapter's job in this case is to ensure the listener exists by creating an Interface you can initialize the listener through.
public interface onRecyclerViewItemClickListener {
void onItemClickListener(View view, int position);
}
After you've defined the information you would like the interface to hold (E.G. the component and it's position), you can then create a function in which the adapter will call to apply the logic from your Activity (same way you would called View.OnClickListener) but by creating a setOnItemClickListener, you can customize it.
public void setOnItemClickListener(onRecyclerViewItemClickListener mItemClickListener) {
this.mItemClickListener = mItemClickListener;
}
This function then needs onRecyclerViewItemClickListener variable passed to it, as seen in your MainActivity. new RecyclerViewAdapter.onRecyclerViewItemClickListener() in this case it's the interface you created before with the method inside that would need to be implemented hence the
#Override
public void onItemClickListener(View view, int position) {
}
is called.
All the ViewHolder does in this scenario is pass the information (The components it's self and the position) into the onItemClickListener with the components attached (inside the onClick function) to finalize the actual click functionality.
if you would like me to update the explanation in anyway, let me know.
I think you are stuck with handling multiple clicks on ReceylerView if that is the case then let me share you the a code snippet from my project. That's how i handle the click in RecyclerView
public class ExploreItemAdapter extends RecyclerView.Adapter<ExploreItemAdapter.ViewHolder> {
private WSResponseDTO<Data> wsResponseDTO;
public ExploreItemAdapter(WSResponseDTO<Data> wsResponseDTO) {
this.wsResponseDTO = wsResponseDTO;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.consumer_dashboard_item, parent, false);
return new ViewHolder(view);
}
#Override
public void onBindViewHolder(ViewHolder holder, final int position) {
holder.tvCompanyName.setText(wsResponseDTO.getData().getPosts().get(position).getStoreInfo().getStoreName());
holder.tvBranchName.setText("(" + wsResponseDTO.getData().getPosts().get(position).getStoreInfo().getBranchName() + ")");
holder.tvLikes.setText(wsResponseDTO.getData().getPosts().get(position).getPost().getFavoriteCount() + "");
holder.tvShares.setText(wsResponseDTO.getData().getPosts().get(position).getPost().getShareCount() + "");
holder.validity.setText(wsResponseDTO.getData().getPosts().get(position).getPost().getValidFrom() + "-" +
wsResponseDTO.getData().getPosts().get(position).getPost().getValidTo());
holder.sTime.setText(wsResponseDTO.getData().getPosts().get(position).getPost().getTime());
holder.tvTitle.setText(wsResponseDTO.getData().getPosts().get(position).getPost().getHeading());
holder.cardView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(view.getContext(), "card is touched", Toast.LENGTH_SHORT).show();
view.getContext().startActivity(new Intent(view.getContext(), ConsumerDetailOfferActivity.class).putExtra("post", wsResponseDTO.getData().getPosts().get(position)));
}
});
}
#Override
public int getItemCount() {
return wsResponseDTO.getData().getPosts().size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
#BindView(R.id.card_explore)
CardView cardView;
#BindView(R.id.tv_company_name)
TextView tvCompanyName;
#BindView(R.id.tv_branch_name)
TextView tvBranchName;
#BindView(R.id.tv_title)
TextView tvTitle;
#BindView(R.id.tv_like_count)
TextView tvLikes;
#BindView(R.id.tv_share_count)
TextView tvShares;
#BindView(R.id.tv_validity)
TextView validity;
#BindView(R.id.tv_sTime)
TextView sTime;
public ViewHolder(View itemView) {
super(itemView);
ButterKnife.bind(this, itemView);
}
}
}
you can set click listener to any item in bindViewHolder() like i did for cardView I hope this will help some.
I have two View holders . On clicking a button in one view I want a text to get updated in another view of the Recycler.
It works fine with getRootview().
But on scrolling when the view gets hidden, recycler crashes (as getRootView no longer returns anything).
How can I implement this ?
ViewHolder1:
public static class CartHeader extends RecyclerView.ViewHolder {
public TextView list_cart_header_textView_total;
private TextView list_cart_header_textView_title;
}
ViewHolder2:
public class CartDBItem extends RecyclerView.ViewHolder implements View.OnClickListener {
private ImageView list_cart_product_imageView_add;
}
onClick of list_cart_product_imageView_add:
CartHeader ch=new CartHeader(view.getRootView());
storeHeader=Double.parseDouble(ch.list_cart_header_textView_total.getText().toString());
Lists in Android use the Model-View-Controller paradigm. The RecyclerView is the View, of course, and the adapter is the Model.
Within the Controller (onClick handler), when you want to change something in the View you change the Model then update the View. So you change the text at its source in the adapter, then call notifyDataSetChanged() to let the RecyclerView know to refresh its views from the adapter.
You should only access view holders when creating their layouts or binding their data.
I am working on xamarin android apps. I used recycler view for displaying the images in each row. Now for each item image there is some link which I need to redirect. How can I achieve this onclick action for each image in recycler view.
Please help me in this regard.
Thanks
When creating a recycler view, you need to create a RecyclerView adapter which (among other things) implements methods for creating and binding a viewholder to the item in the recycler view. Somewhere in your code (oftentimes within this recycler view adapter class), you need to define the viewholder that you will use for your recyclerview items. This is where you should assign the onClickListener to your imageView.
Here is an example of a viewholder definition that I think may help you:
public class YourViewHolder extends RecyclerView.ViewHolder {
protected ImageView yourImage;
public YourViewHolder(View v) {
super(v);
final View theView = v;
yourImage = (ImageView) v.findViewById(R.id.yourImage);
yourImage.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// image clicked... do something
}
});
}
}
Let me know if you need more information on how to set up the recycler view adapter class (I have assumed that you already have done this, but I could be mistaken).