Android SwipeRefresh RecyclerView Tutorial

android swipe to refresh

This is a Swipe To Refresh tutorial.

We want that when the user pulls at the top of our layout we refresh data. This is a very popular technique for refreshing data that is implemented by so many mobile apps.

In this case our widget is a recyclerview.

Let's go.

1. Create Basic Activity Project

  1. First create an empty project in android studio. Go to File --> New Project.

  2. Type the application name and choose the company name. New Project Dialog

  3. Choose minimum SDK. Choose minimum SDK

  4. Choose Basic activity. Choose Empty Activity

  5. Click Finish. Finish

Basic activity will have a toolbar and floating action button already added in the layout

Normally two layouts get generated with this option:

No. Name Type Description
1. activity_main.xml XML Layout Will get inflated into MainActivity Layout.Typically contains appbarlayout with toolbar.Also has a floatingactionbutton.
2. content_main.xml XML Layout Will be included into activity_main.xml.You add your views and widgets here.
3. MainActivity.java Class Main Activity.

In this example I used a basic activity.

The activity will automatically be registered in the android_manifest.xml. Android Activities are components and normally need to be registered as an application component.

If you've created yours manually then register it inside the <application>...<application> as following, replacing the MainActivity with your activity name:


        <activity android:name=".MainActivity">

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

You can see that one action and category are specified as intent filters. The category makes our MainActivity as launcher activity. Launcher activities get executed first when th android app is run.

Advantage of Creating Basic Activity project

You can optionally choose empty activity over basic activity for this project.

However basic activity has the following advantages:

No. Advantage
1. Provides us a readymade toolbar which gives us actionbar features yet easily customizable
2. Provides us with appbar layout which implements material design appbar concepts.
3. Provides a FloatinActionButton which we can readily use to initiate quick actions especially in examples like these.
4. Decouples our custom content views and widgets from the templating features like toolbar.

Generated Project Structure

AndroidStudio will generate for you a project with default configurations via a set of files and directories.

Here are the most important of them:

No. File Major Responsibility
1. build/ A directory containing resources that have been compiled from the building of application and the classes generated by android tools. Such a tool is the R.java file. R.java file normally holds the references to application resources.
2. libs/ To hold libraries we use in our project.
3. src/main/ To hold the source code of our application.This is the main folder you work with.
4. src/main/java/ Contains our java classes organized as packages.
5. src/main/res/ Contains our project resources folders as follows.
6. src/main/res/drawable/ Contains our drawable resources.
7. src/main/res/layout/ Contains our layout resources.
8. src/main/res/menu/ Contains our menu resources XML code.
9. src/main/res/values/ Contains our values resources XML code.These define sets of name-value pairs and can be strings, styles and colors.
10. AndroidManifest.xml This file gets autogenerated when we create an android project.It will define basic information needed by the android system like application name,package name,permissions,activities,intents etc.
11. build.gradle Gradle Script used to build the android app.

2. Add Dependencies

In your build.gradle:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.2.1'
    compile 'com.android.support:design:23.2.1'
    compile 'com.android.support:cardview-v7:23.2.1'

}

3. Create User Interface

User interfaces are typically created in android using XML layouts as opposed by direct java coding.

This is an example fo declarative programming.

Advantages of Using XML over Java
No. Advantage
1. Declarative creation of widgets and views allows us to use a declarative language XML which makes is easier.
2. It's easily maintanable as the user interface is decoupled from your Java logic.
3. It's easier to share or download code and safely test them before runtime.
4. You can use XML generated tools to generate XML

Here are our layouts for this project:

(a). activity_main.xml

  • This layout gets inflated to MainActivity user interface.
  • It includes the content_main.xml.

Here are some of the widgets, views and viewgroups that get employed"

No. View/ViewGroup Package Role
1. CordinatorLayout android.support.design.widget Super-powered framelayout that provides our application's top level decoration and is also specifies interactions and behavioros of all it's children.
2. AppBarLayout android.support.design.widget A LinearLayout child that arranges its children vertically and provides material design app bar concepts like scrolling gestures.
3. ToolBar <android.support.v7.widget A ViewGroup that can provide actionbar features yet still be used within application layouts.
4. FloatingActionButton android.support.design.widget An circular imageview floating above the UI that we can use as buttons.
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
    android:fitsSystemWindows="true"
    tools:context="com.tutorials.hp.swiperefreshrecyclerview.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

(b). content_main.xml

This layout gets included in your activity_main.xml. We define recyclerview inside a SwipeRefreshLayout here.

<?xml version="1.0" encoding="utf-8"?>
<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.tutorials.hp.swiperefreshrecyclerview.MainActivity"
    tools:showIn="@layout/activity_main">

    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/swiper"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/mRecycler"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            >
        </android.support.v7.widget.RecyclerView>

    </android.support.v4.widget.SwipeRefreshLayout>
</RelativeLayout>

(c). model.xml

RecyclerViewItem row model.

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_margin="10dp"
    card_view:cardCornerRadius="10dp"
    card_view:cardElevation="10dp"

    android:layout_height="wrap_content">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/movieImage"
            android:padding="10dp"
            android:src="@drawable/ghost" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="Name"
            android:id="@+id/nameTxt"
            android:padding="10dp"
            android:textColor="@color/colorAccent"
            android:layout_below="@+id/movieImage"
            android:layout_alignParentLeft="true"
             />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text=" John Doe a former FBI Agent and now Physics teacher .is wrongly accussed of murdering an innocent child.He makes it his business to find the bad guys who did taht.He convinces hacker Aram to join him.....
            "
            android:id="@+id/descTxt"
            android:padding="10dp"
            android:layout_below="@+id/nameTxt"
            android:layout_alignParentLeft="true"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="TV Show"
            android:id="@+id/posTxt"
            android:padding="10dp"

            android:layout_below="@+id/movieImage"
            android:layout_alignParentRight="true" />

        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/chk"
            android:layout_alignParentRight="true"
            />

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

4. Java Classes

(a). ItemClickListener.java

package com.tutorials.hp.swiperefreshrecyclerview;

public interface ItemClickListener {

    void onItemClick(int pos);

}

(b). Movie.java

Our data object.

package com.tutorials.hp.swiperefreshrecyclerview;

public class Movie {
    private String name;
    private int image;

    public Movie(String name, int image) {
        this.name = name;
        this.image = image;
    }

    public String getName() {
        return name;
    }

    public int getImage() {
        return image;
    }
}

(c). MyHolder.java

Our RecyclerView ViewHolder class:

package com.tutorials.hp.swiperefreshrecyclerview;

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class MyHolder extends RecyclerView.ViewHolder implements View.OnClickListener{

    ImageView img;
    TextView nameTxt;
    ItemClickListener itemClickListener;

    public MyHolder(View itemView) {
        super(itemView);

        img= (ImageView) itemView.findViewById(R.id.movieImage);
        nameTxt= (TextView) itemView.findViewById(R.id.nameTxt);

        itemView.setOnClickListener(this);
    }

    public void setItemClickListener(ItemClickListener ic)
    {
        this.itemClickListener=ic;
    }

    @Override
    public void onClick(View v) {
        this.itemClickListener.onItemClick(getLayoutPosition());
    }
}

(d). MyAdapter.java

Our RecyclerView Adapter class.

package com.tutorials.hp.swiperefreshrecyclerview;

import android.content.Context;
import android.os.Handler;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.Random;

public class MyAdapter extends RecyclerView.Adapter<MyHolder> {

    Context c;
    ArrayList<Movie> movies;
    SwipeRefreshLayout swiper;

    public MyAdapter(Context c, ArrayList<Movie> movies, SwipeRefreshLayout swiper) {
        this.c = c;
        this.movies = movies;
        this.swiper = swiper;
    }

    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v= LayoutInflater.from(parent.getContext()).inflate(R.layout.model,parent,false);
        MyHolder holder=new MyHolder(v);

        return holder;
    }

    @Override
    public void onBindViewHolder(MyHolder holder, int position) {
         holder.nameTxt.setText(movies.get(position).getName());
        holder.img.setImageResource(movies.get(position).getImage());

        holder.setItemClickListener(new ItemClickListener() {
            @Override
            public void onItemClick(int pos) {
                Toast.makeText(c, movies.get(pos).getName(), Toast.LENGTH_SHORT).show();
            }
        });

        swiper.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                refresh();
            }
        });
    }

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

    private void refresh()
    {
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                movies.add(0,movies.get(new Random().nextInt(movies.size())));

                MyAdapter.this.notifyDataSetChanged();

                swiper.setRefreshing(false);
            }
        },3000);
    }
}

(e). MainActivity.java

Our Main Activity.

package com.tutorials.hp.swiperefreshrecyclerview;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    RecyclerView rv;
    SwipeRefreshLayout swiper;
    MyAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        rv= (RecyclerView) findViewById(R.id.mRecycler);
        swiper= (SwipeRefreshLayout) findViewById(R.id.swiper);

        rv.setLayoutManager(new LinearLayoutManager(this));
        rv.setItemAnimator(new DefaultItemAnimator());

        final ArrayList<Movie> movies;
        movies=getMovies();
        adapter=new MyAdapter(this,movies,swiper);

        rv.setAdapter(adapter);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, String.valueOf(movies.size()), Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

    private ArrayList<Movie> getMovies()
    {

        //COLECTION OF  MOVIES
        ArrayList<Movie> movies=new ArrayList<>();

        Movie movie=new Movie("Game Of Thrones",R.drawable.thrones);
        movies.add(movie);

        movie=new Movie("BlackList",R.drawable.red);
        movies.add(movie);

        movie=new Movie("Breaking Bad",R.drawable.breaking);
        movies.add(movie);

        movie=new Movie("Shuttle Carrier",R.drawable.shuttlecarrier);

        movies.add(movie);

        movie=new Movie("Fruits",R.drawable.fruits);
        movies.add(movie);

        movie=new Movie("Crisis",R.drawable.crisis);
        movies.add(movie);

        movie=new Movie("Ghost Rider",R.drawable.rider);
        movies.add(movie);

        movie=new Movie("Star Wars",R.drawable.starwars);
        movies.add(movie);

        movie=new Movie("Men In Black",R.drawable.meninblack);
        movies.add(movie);

        return movies;
    }

}

How do You Feel after reading this?

According to scientists, we humans have 8 primary innate emotions: joy, acceptance, fear, surprise, sadness, disgust, anger, and anticipation. Feel free to tell us how you feel about this article using these emotes or via the comment section. This feedback helps us gauge our progress.

Help me Grow.

I set myself some growth ambitions I desire to achieve by this year's end regarding this website and my youtube channel. Am halfway. Help me reach them by:




Recommendations


What do You Think


Previous Post Next Post