How to use the adapter of Android Recyclerview V7 framework
How to use the adapter of Android Recyclerview V7 framework
In Android development, RecyclerView is a very practical control that is used to display a list of large amounts of data or layout of grid forms.The RecyclerView V7 framework provides a more flexible and efficient way to manage this data.This article will introduce the adapter of how to use the RecyclerView V7 framework to present data and provide some Java code examples.
First of all, we need to add the Recyclerview V7 framework to the project.In the built.gradle file of the project, add the following code:
dependencies {
implementation 'androidx.recyclerview:recyclerview:<version>'
}
Add a RecyclerView control to the layout file:
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
Next, we need to create an adapter class to manage the presentation of data.First of all, create a Class ViewHolder type inherited from the RecyclerView.adapter and specify the data model.For example, we create a adapter class called MyAdapter:
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private List<String> data;
public MyAdapter(List<String> data) {
this.data = data;
}
// Create a ViewHolder class
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView textView;
public ViewHolder(View itemView) {
super(itemView);
textView = itemView.findViewById(R.id.textView);
}
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
// Create a view
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
// Bind data
String text = data.get(position);
holder.textView.setText(text);
}
@Override
public int getItemCount() {
// Return the number of data items
return data.size();
}
}
In the above code, we created a viewholder class to cache view, and created a view in the oncreateViewHolder method, and associated it with ViewHolder.In the OnbindViewHolder method, we obtain data from the corresponding position from the data list and bind it to the view of the viewholder.Finally, the getItemCount method returns the number of data items.
We can now use adapters in Activity or Fragment to present data.First, find the RecyclerView control:
RecyclerView recyclerView = findViewById(R.id.recyclerView);
Then, create an adapter instance and set it to Recyclerview:
List<String> data = new ArrayList<>();
// Add data to the list
// ...
MyAdapter adapter = new MyAdapter(data);
recyclerView.setAdapter(adapter);
Finally, we need to choose a suitable layout manager to manage the layout of RecyclerView.For example, using linearlayoutManager to create a vertical linear layout:
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
The above is the basic step of using Android Reyclerview V7 framework.By creating a custom adapter class, we can manage the presentation of data more flexibly and implement the layout of the list or grid form.
I hope this article will help you understand the adapters of Android Reyclerview V7 framework.If you have any questions, please ask at any time.
