How to Implement Load More in #RecyclerView


At all apps like facebook, Twitter …etc

you will notice that when you scroll down you will see progress bar and more data will loaded at this case we this app load only some of data and when user scroll more data will loaded

Now we will Know how to do this in android studio

1-Start new project and name it what you want

2-Open your build.gradle and add next dependencies

compile 'com.android.support:recyclerview-v7:23.1.0'
compile 'com.android.support:cardview-v7:23.1.0'

3-At your main_activity .xml add the RecyclerView

<?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="match_parent"
android:fitsSystemWindows="true"
android:orientation="vertical">

<android.support.v7.widget.RecyclerView
android:id="@+id/my_recycler_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_margin="5dp"
android:layout_weight="1"
android:scrollbars="vertical" />


<TextView
android:id="@+id/empty_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="No Records"
android:visibility="gone" />


</LinearLayout>

4-Now under layout directory add new layout resource file and name it item.xml and add the following xml code

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
card_view:cardCornerRadius="5dp"
card_view:cardUseCompatPadding="true">

<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="?android:selectableItemBackground">

<TextView
android:id="@+id/tvName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="5dp"
android:text="Name"
android:textColor="@android:color/black"
android:textSize="18sp" />

<TextView
android:id="@+id/tvEmailId"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/tvName"
android:layout_margin="5dp"
android:text="Email Id"
android:textColor="@android:color/black"
android:textSize="12sp" />
</RelativeLayout>

</android.support.v7.widget.CardView>

5- At this step we will add out progress bar layout that will show when loade more data under layout directory add new layout resource file and name it progressbar.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="match_parent"
android:orientation="vertical" >

<ProgressBar
android:id="@+id/progressBar1"
android:layout_width="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_height="wrap_content" />

</LinearLayout>

6- Add new class and name it Student.java it will be youe model and copy past the follwing code

package com.asi.lodemorerecy;

import java.io.Serializable;

public class Student implements Serializable {

private static final long serialVersionUID = 1L;

private String name;

private String emailId;

public Student() {

}
public Student(String name, String emailId) {
this.name = name;
this.emailId = emailId;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getEmailId() {
return emailId;
}

public void setEmailId(String emailId) {
this.emailId = emailId;
}


}

7-Now you will make new Interface to Implement the loade more by what you want OnLoadMoreListener copy past the next code at your interface

package com.asi.lodemorerecy;

public interface OnLoadMoreListener {
void onLoadMore();
}

8-Working on the recyclerview Adapter see the next code study it

and copy past on you Adapter

package com.asi.lodemorerecy;


import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import java.util.List;



public class DataAdapter extends RecyclerView.Adapter {
private final int VIEW_ITEM = 1;
private final int VIEW_PROG = 0;

private List<Student> studentList;

// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 5;
private int lastVisibleItem, totalItemCount;
private boolean loading;
private OnLoadMoreListener onLoadMoreListener;



public DataAdapter(List<Student> students, RecyclerView recyclerView) {
studentList = students;

if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {

final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView
.getLayoutManager();


recyclerView
.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView,
int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);

totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager
.findLastVisibleItemPosition();
if (!loading
&& totalItemCount <= (lastVisibleItem + visibleThreshold)) {
// End has been reached
// Do something
if (onLoadMoreListener != null) {
onLoadMoreListener.onLoadMore();
}
loading = true;
}
}
});
}
}

@Override
public int getItemViewType(int position) {
return studentList.get(position) != null ? VIEW_ITEM : VIEW_PROG;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
RecyclerView.ViewHolder vh;
if (viewType == VIEW_ITEM) {
View v = LayoutInflater.from(parent.getContext()).inflate(
R.layout.list_row, parent, false);

vh = new StudentViewHolder(v);
} else {
View v = LayoutInflater.from(parent.getContext()).inflate(
R.layout.progressbar_item, parent, false);

vh = new ProgressViewHolder(v);
}
return vh;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof StudentViewHolder) {

Student singleStudent= (Student) studentList.get(position);

((StudentViewHolder) holder).tvName.setText(singleStudent.getName());

((StudentViewHolder) holder).tvEmailId.setText(singleStudent.getEmailId());

((StudentViewHolder) holder).student= singleStudent;

} else {
((ProgressViewHolder) holder).progressBar.setIndeterminate(true);
}
}

public void setLoaded() {
loading = false;
}

@Override
public int getItemCount() {
return studentList.size();
}

public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
this.onLoadMoreListener = onLoadMoreListener;
}


//
public static class StudentViewHolder extends RecyclerView.ViewHolder {
public TextView tvName;

public TextView tvEmailId;

public Student student;

public StudentViewHolder(View v) {
super(v);
tvName = (TextView) v.findViewById(R.id.tvName);

tvEmailId = (TextView) v.findViewById(R.id.tvEmailId);

v.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
Toast.makeText(v.getContext(),
"OnClick :" + student.getName() + " \n "+student.getEmailId(),
Toast.LENGTH_SHORT).show();

}
});
}
}

public static class ProgressViewHolder extends RecyclerView.ViewHolder {
public ProgressBar progressBar;

public ProgressViewHolder(View v) {
super(v);
progressBar = (ProgressBar) v.findViewById(R.id.progressBar1);
}
}

9-The final step at this tutorial is implement all we do befor at your MainActivity.java
package com.asi.lodemorerecy;

import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {

private Toolbar toolbar;

private TextView tvEmptyView;
private RecyclerView mRecyclerView;
private DataAdapter mAdapter;
private LinearLayoutManager mLayoutManager;

private List<Student> studentList;


protected Handler handler;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
tvEmptyView = (TextView) findViewById(R.id.empty_view);
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
studentList = new ArrayList<Student>();
handler = new Handler();
if (toolbar != null) {
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Android Students");

}

loadData();

// use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
mRecyclerView.setHasFixedSize(true);

mLayoutManager = new LinearLayoutManager(this);

// use a linear layout manager
mRecyclerView.setLayoutManager(mLayoutManager);

// create an Object for Adapter
mAdapter = new DataAdapter(studentList, mRecyclerView);

// set the adapter object to the Recyclerview
mRecyclerView.setAdapter(mAdapter);
// mAdapter.notifyDataSetChanged();


if (studentList.isEmpty()) {
mRecyclerView.setVisibility(View.GONE);
tvEmptyView.setVisibility(View.VISIBLE);

} else {
mRecyclerView.setVisibility(View.VISIBLE);
tvEmptyView.setVisibility(View.GONE);
}

mAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
@Override
public void onLoadMore() {
//add null , so the adapter will check view_type and show progress bar at bottom
studentList.add(null);
mAdapter.notifyItemInserted(studentList.size() - 1);

handler.postDelayed(new Runnable() {
@Override
public void run() {
// remove progress item
studentList.remove(studentList.size() - 1);
mAdapter.notifyItemRemoved(studentList.size());
//add items one by one
int start = studentList.size();
int end = start + 20;

for (int i = start + 1; i <= end; i++) {
studentList.add(new Student("Student " + i, "AndroidStudent" + i + "@gmail.com"));
mAdapter.notifyItemInserted(studentList.size());
}
mAdapter.setLoaded();
//or you can add all at once but do not forget to call mAdapter.notifyDataSetChanged();
}
}, 2000);

}
});

}


// load initial data
private void loadData() {

for (int i = 1; i <= 20; i++) {
studentList.add(new Student("Student " + i, "androidstudent" + i + "@gmail.com"));

}


}