Skip to main content

RETROFIT HTTP LIBRARY - ANDROID TUTORIAL

Retrofit is same as Volley and it is definitely the better alternative to volley in terms of ease of use, performance, extensibility and other things. It is a type-­safe REST client for Android built by Square. Using this tool android developer can make all network stuff much more easier. 

Now let’s see the action of retrofit by creating a new project. As an example, we are going to download some json and show it in RecyclerView as a list.

Step 1. Create a new project in Android Studio

Step 2. Open build.gradle and add Retrofit
      compile 'com.squareup.retrofit2:retrofit:2.1.0'

make change over dependencies

dependencies {

    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.android.support:design:23.1.0'
    compile 'com.squareup.retrofit2:retrofit:2.1.0'
    compile 'com.android.support:cardview-v7:23.1.1'
    compile 'com.github.bumptech.glide:glide:3.7.0'
}

Step 3. Since we are working with network operations we need to add INTERNET permissions in AndroidManifest.xml file
<uses-permission android:name="android.permission.INTERNET"/>

Step 4. Open activity_main.xml and replace the design

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.ufours.retrofit_sample.MainActivity">

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

</RelativeLayout>

Step 5. Create new xml card_view.xml and replace the design

<?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:padding="1dp">

    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/card_view">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="5dp">

            <ImageView
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:id="@+id/person_photo"
                android:layout_alignParentLeft="true"
                android:layout_alignParentTop="true"
                android:layout_marginRight="16dp" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/person_name"
                android:layout_toRightOf="@+id/person_photo"
                android:layout_alignParentTop="true"/>

        </RelativeLayout>

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

</LinearLayout>

Step 6. Create an interface APICallInterface
public interface APICallInterface {
   @GET @Headers("Connection:close")
   Call<ResponseBody> callAPI(@Url String url);
   @GET @Headers("Connection:close")
   Call<ResponseBody> callAPI(@Url String url, @QueryMap Map<String, String> parameters);
   @POST @Headers("Connection:close")
   Call<ResponseBody> postToAPI(@Url String url, @Body RequestBody parameter);
   @PUT @Headers("Connection:close")
   Call<ResponseBody> putToAPI(@Url String url, @Body RequestBody parameter);

}


Step 7. Open MainActivity.java and replace the coding

public class MainActivity extends AppCompatActivity {


    private CoordinatorLayout coordinatorLayout;
    Retrofit retrofit;
    APICallInterface service;
    Call<ResponseBody> call = null;
    static ProgressDialog pDialog;
    private int mStatusCode;
    private static RecyclerView recyclerView;
    private RecyclerView.LayoutManager m_LayoutManager;

    String strTesti, strUrl;;
    public static String TAG_IMAGE_URL = "Image";
    public static String TAG_CONTENT = "content";
    ArrayList<HashMap<String, String>> arraySend = new ArrayList<>();
    CustomAdapter customAdapter;
    //Reponsecode
    public static final int SUCEESSRESPONSECODE = 200;
    public static final int FAILURERESPONSECODE = 204;
    public static final int INTERNALERRORRESPONSECODE = 500;
    public static final int ERRORRESPONSECODE = 400;

    String base_url = "http://YOUR_URL_HERE.com/";
    String url = "YOUR_METHOD_URL_HERE";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        retrofit = new Retrofit.Builder()
                .baseUrl(base_url)
                .build();
        service = retrofit.create(APICallInterface.class);

        recyclerView = (RecyclerView)findViewById(R.id.idRecycler);
        recyclerView.setHasFixedSize(true);
        m_LayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(m_LayoutManager);

        if (isConnectingToInternet(MainActivity.this)) {
        loadImage();
        }else{
            alertbox(MainActivity.this,
                    getString(R.string.str_networkmessage),
                    getString(R.string.str_networktitlemessage));
        }
    }

    private void loadImage() {

        showDialog(MainActivity.this, "Loading");
        call = service.callAPI(url);

        call.enqueue(new Callback<ResponseBody>() {

            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {

                try{
                    mStatusCode = response.code();

                    if (mStatusCode == SUCEESSRESPONSECODE) {

                        JSONArray resultarray = new JSONArray(response.body().string());
                        for (int i = 0; i < resultarray.length(); i++) {
                            JSONObject nmcdata = resultarray.getJSONObject(i);

                            strUrl = nmcdata.getString(TAG_IMAGE_URL);
                            strTesti = nmcdata.getString(TAG_CONTENT);

                            HashMap<String, String> objMap = new HashMap<>();
                            objMap.put(TAG_IMAGE_URL, strUrl);
                            objMap.put(TAG_CONTENT, strTesti);

                            arraySend.add(objMap);
                        }
                        dismissDialog();

                    }else if (mStatusCode == FAILURERESPONSECODE) {
                        dismissDialog();
                        Snackbar snackbar = Snackbar.make(coordinatorLayout,
                                response.errorBody().string(), Snackbar.LENGTH_LONG);
                        snackbar.show();

                    } else {
                        if (mStatusCode == INTERNALERRORRESPONSECODE) {
                            dismissDialog();
                            Snackbar snackbar = Snackbar.make(coordinatorLayout,
                                    response.errorBody().string(), Snackbar.LENGTH_LONG);
                            snackbar.show();
                        }
                    }

                }catch (JSONException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                if (arraySend.size() > 0) {
                    customAdapter = new CustomAdapter(MainActivity.this, arraySend, recyclerView);
                    recyclerView.setAdapter(customAdapter);
                }
            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {
            }
        });
    }

    //internet_connection_check
    public boolean isConnectingToInternet(Context _context) {
        ConnectivityManager connectivity = (ConnectivityManager) _context
                .getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo info = connectivity.getActiveNetworkInfo();
        if (info == null) {
            return false;
        } else
            return true;
    }

    public void alertbox(Context _context, String message, String title) {

        AlertDialog.Builder builder1 = new AlertDialog.Builder(_context);
        builder1.setTitle(title);
        builder1.setMessage(message);
        builder1.setCancelable(true);
        builder1.setPositiveButton("ok", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                dialog.cancel();
            }
        });

        AlertDialog alert11 = builder1.create();
        alert11.show();
    }

    public static void showDialog(Context mContext, String strMessage) {
        try {
            if (pDialog != null)
                if (pDialog.isShowing())
                    pDialog.dismiss();
            pDialog = ProgressDialog.show(mContext, "", strMessage, true);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void dismissDialog() {
        try {
            if (pDialog.isShowing())
                pDialog.dismiss();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

URL used here brings the response as this

Step 8. Create a adapter class CustomAdapter.java 
public class CustomAdapter extends RecyclerView.Adapter{
    RecyclerView mrecyclerview;
    static Context context;
    ArrayList<HashMap<String, String>> Items = new ArrayList<>();

    public CustomAdapter(MainActivity context, ArrayList<HashMap<String, String>> arraySend, RecyclerView recyclerView) {
        this.context = context;
        mrecyclerview = recyclerView;
        Items = arraySend;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        RecyclerView.ViewHolder vh;
        View itemLayoutView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.card_view, null);

        vh = new ViewHolder(itemLayoutView);
        return vh;
    }

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

        try {
            final HashMap<String, String> tempMap = Items.get(position);

            ((ViewHolder) holder).txtConten.setText(tempMap
                    .get(MainActivity.TAG_CONTENT));

            String urlImg = tempMap
                    .get(MainActivity.TAG_IMAGE_URL);
            Glide.with(context)
                    .load(urlImg)
                    .into(((ViewHolder) holder).imgUrl);

        }catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    public int getItemCount() {
        return Items.size();
    }

    private class ViewHolder extends RecyclerView.ViewHolder {
        public TextView txtConten;
        ImageView imgUrl;
        CardView cardview;

        public ViewHolder(View itemLayoutView) {
            super(itemLayoutView);

            cardview = (CardView) itemLayoutView.findViewById(R.id.card_view);
            imgUrl = (ImageView) itemLayoutView.findViewById(R.id.person_photo);
            txtConten = (TextView) itemLayoutView.findViewById(R.id.person_name);

        }
    }
}

Now run the application and the output is as
________________________________________________________
Sourcecode for RetrofitSample.zip

Happy Coding...

Comments

Post a Comment

Popular posts from this blog

Zoom Image - Android Tutorial

Here we are going to see how to zoom an image in Imageview Will see it through a sample 1. Create xml with an ImageView <? xml version="1.0" encoding="utf-8" ?> < androidx.constraintlayout.widget.ConstraintLayout       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"     tools:context=".MainActivity" >     < LinearLayout         android:layout_width="200dp"         android:layout_height="200dp"         app:layout_constraintBottom_toBottomOf="parent"         app:layout_constraintLeft_toLeftOf="parent"         app:layout_constraintRight_toRightOf="parent"    ...
Post a Comment
Read more

Add custom font in Android using Calligraphy library

Are you fed up of Custom Views to set fonts? Or traversing the ViewTree to find TextViews? Sometime we want some other font for our Android application then you can add custom font in Android using Calligraphy library . Dependency Include the dependency Download (.aar) dependencies { compile ‘uk.co.chrisjenx:calligraphy:2.2.0’ } Add Fonts Add your custom fonts to assets/ . All font definitions are relative to this path. On Assets you should right-click New Directory, call it "fonts". In the finder put the .ttf  or .otf  font files in there. Create Class Create a class that extends Application and write this code public class App extends Application { @Override public void onCreate() { super.onCreate(); CalligraphyConfig.initDefault(new CalligraphyConfig.Builder() .setDefaultFontPath("your font path") .setFontAttrId(...
Post a Comment
Read more

Bluetooth Chat Application - Android Tutorial

In this tutorial, we will see about how to design an Android layout for chat application using Chat Bubbles  and the main part is chat via Bluetooth . Main objective of this post is to give an idea about how to allow two-way text chat over Bluetooth in android. Bubbles: Chat bubbles are background image that expands horizontally and vertically as required based on the message posted. Bubbles are Nine-patch Images. Image Nine-patch Image In creating Android chat bubbles, nine-patch image plays a crucial role.  Nine-patch image  is a bitmap which stretches to fit the content posted in the View where it is applied as a background. A NinePatch drawable is a standard PNG image that includes an extra 1-pixel-wide border. It must be saved with the extension  .9.png , and saved into the  res/drawable/  directory of your project. The border is used to define the stretchable and static areas of the image. You indicate a stretchable section ...
8 comments
Read more