Custom View to be Used as a Nested View or as a RecyclerView Item view in Android

Question

I'm new to android, but have a good JavaFX experience. I'm trying to create a custom view that i can reuse, but having a hard time figuring out the correct way to do it.

In javafx i could achieve this by: Creating a separate fxml file defining the layout of the custom view, then create a controller class linked to the fxml file, in that class, i'd have a method to retrieve the data model of the controller and use it to fill in the labels, etc.

The custom view i want would be

• Constrained Layout
  • TextView (constrained to right anchor)
  • Round TextView (constrained to left anchor)

What is the best way to do this in android? Also, Is it possible to achieve this with a RecyclerView? If yes, how can i use a custom view for each item and set its data?

Answer 1

The question is broad. You may need additional research on creating views

1. Create a recyclerview in the main.xml,
2. a separate file with an item view.
   • You have 3 views in your item view - white background with margins (linearlayout?), right textView, and left textview.
   • The left textview should have android:background="drawable/round_shape" and round_shape.xml defined in your drawables folder. Everything is done in 3 xml files, main.xml for recyclerview, item.xml, round_background.xml. Then, the recyclerview adapter to bind the textviews with your array, and recyclerview initialization

A typical RV adaptor

 public class MyRV extends RecyclerView.Adapter<MyRV.ViewHolder> {

private List<MyModelItemWith2Strings> mDataSet; // You may need to setup an array, 
                   // with 2 String objects - for the right and left textviews


// Use an array of class with 2 elements rather than <String>, e.g. List<MyModelItemWith2Strings>
// pass your model here
 // this setData will be used to provide the contents for the textviews
void setData(List< /* set your 2 string class here*/ > dataSet) {
    mDataSet = dataSet;
}

static class ViewHolder extends RecyclerView.ViewHolder {

   // Here you bind item TV's
   // first you declare textviews that you will use to fill with data
   // Add any other item views you will need to fill in

    public TextView tv;
    public TextView tv2;

    public ViewHolder(LinearLayout v) {
        super(v);

        // Bind itemview views here. Put R.id.tv from your itemview.xml

        tv = v.findViewById(R.id.....);
         tv2 = v...
    }
}

// Add your itemview layout here
@Override
public MyRV.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    LinearLayout v = (LinearLayout) LayoutInflater.from(parent.getContext())
        .inflate(/***R.layout.item_view***/, parent, false);
    ViewHolder vh = new ViewHolder(v);
    return vh;
}


@Override
public void onBindViewHolder( MyRV.ViewHolder h, int position) {

    // get content from your model (the above list) and fill in the the itemview textviews

    String a= mDataSet.get(position).getItem1();
    String b = mDataSet.get(position). getItem2();
    ...

    h.tv.setText(a);
    // set clickers if you want to. The clicker class is below.
    h.tv.setOnClickListener(new Click(position));

    h.tv2.setText(...)
}

// This is obligatory to pass for your RV to initialize. It won't work if you don' t tell Android how to count your array soze
@Override
public int getItemCount() {
    return mDataSet.size();
}

// These are my implementation of clickers. I prefer to put them in the nested class of the adapter.
private class Click  implements OnClickListener {
    private int pos;
    Click(int position) {
        pos = position;
    }

    @Override
    public void onClick(View p1) {
        // get data from your array on click
        mDataSet.get(pos);
        // Use pos as position on the array, mData.get(pos)
    }
    }
}

Then, in your main class set a recyclerview

   RecyclerView rv = (RecyclerView) findViewById(R.id.rv_In_Main_Xml);

    // just additional tunings. 
    rv.setHasFixedSize(true);
    rv.setLayoutManager(new LinearLayoutManager(context)); // <- context = this, if you are in the Main activity

Then set the adapter

MyRV rva = new MyRV();
rva.setData(myArray_with_2_string_objects_to_fill_tvs);
rv.setAdaptor(rva);

And your recycler view gets filled with data