How to Call Simple  POST method API

Objective :-

                  

               The main objective of this post is to help you understand how to call simple post method  API  in your android Application.

You will get Final Output :-

   

First implement below Dependencies in app:Build.gradle

compile 'com.android.support:recyclerview-v7:26.1.0'

compile 'com.android.support:cardview-v7:26.1.0'

compile 'com.squareup.retrofit2:retrofit:2.1.0'
compile 'com.squareup.retrofit2:converter-gson:2.1.0'
compile 'com.squareup.okhttp3:logging-interceptor:3.4.1'
compile 'com.squareup.okhttp:okhttp:2.4.0'

In This activity you need  2 XML files.

• activity_view_productname.xml:-

<layout xmlns:card_view="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">


        <android.support.v7.widget.CardView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="8dp"
            card_view:cardCornerRadius="10dp">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center"
                android:orientation="vertical">


                <android.support.v7.widget.RecyclerView

                    android:id="@+id/rvCategoryList"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:layout_marginTop="10dp">

                </android.support.v7.widget.RecyclerView>
            </LinearLayout>

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

view_product_name.xml:-


<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="@dimen/_10sdp"
    android:visibility="visible">

    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/_4sdp"
        android:layout_gravity="center">


            <TextView
                android:id="@+id/txtCategoryName"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:gravity="center"
                android:ellipsize="end"
                android:lines="3"
                android:maxLines="3"
                android:text="medicine name"
                android:textColor="@color/colorGray"
                android:textSize="@dimen/_15sdp"
                android:textStyle="bold" />
    </android.support.v7.widget.CardView>

</LinearLayout>
</layout>

In this program use the POST Request method API.
First declare API in ApiEndpointInterface interface Class


ApiEndpointInterface:-


public interface ApiEndpointInterface {

    @Multipart    @POST("Welcome/dashboard")
    Call<ArrayList<ProductNameInfo>> ProductData(@Part("key") RequestBody key);
}



In this Api Classs you can use OkHttps Credentials is "Key".
User was get data for above OkHttps Credentials.
Multipart requests are used when @Multipart is present on the method. Parts are declared using the @Part annotation.
Multipart parts use one of Retrofit's converters or they can implement RequestBody to handle their own serialization.
After make a Retrofit Builder Class.



RetrofitBuilder.java:-



public class RetrofitBuilder {
    public static final String BASE_URL = "http://www.erestaurantapp.com/EmedDictionary/index.php/";

    public  static final RetrofitBuilder retrofitBuilder=new RetrofitBuilder();
    private RetrofitBuilder(){

    }
    public static RetrofitBuilder getInstance() {
        return retrofitBuilder;
    }

    public ApiEndpointInterface getRetrofit(final Context context) {

        final OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

        final Gson gson = new GsonBuilder().registerTypeAdapterFactory(new ItemTypeAdapterFactory())
                .setLenient().setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ").create();



        final Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .client(httpClient.build())
                .addConverterFactory(GsonConverterFactory.create(gson))
                .build();

        return retrofit.create(ApiEndpointInterface.class);
    }


}



In the Retrofit Builder class i have add the BASE_URL.
Retrofit.Builder class - Instance which uses the interface 

     and the Builder API which allows defining the URL end point for 
     the HTTP operation.

If you need to communicate with an API that uses a content-format 

     that Retrofit does not support out of the box (e.g. YAML, txt, custom format)
     or you wish to use a different library to implement an existing format, you can
    easily create your own converter. Create a class that extends the Converter.Factor           and pass in an instance when building your adapter.


ItemTypeAdapterFactory:-


class ItemTypeAdapterFactory implements TypeAdapterFactory {
    private static final String KEY_STATUS = "status";
    private static final String KEY_MESSAGE = "msg";
    private static final String KEY_RESULT = "result";


    @Override    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
        final TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
        final TypeAdapter<JsonElement> elementAdapter = gson.getAdapter(JsonElement.class);

        return new TypeAdapter<T>() {

            public void write(JsonWriter out, T value) throws IOException {
                delegate.write(out, value);
            }

            public T read(JsonReader in) throws IOException {

                JsonElement jsonElement = elementAdapter.read(in);
                if (jsonElement.isJsonObject()) {

                    final JsonObject jsonObject = jsonElement.getAsJsonObject();

                    String status = "";
                    String message = "";
                    if (jsonObject.has(KEY_STATUS) && jsonObject.has(KEY_MESSAGE)) {
                        status = jsonObject.get(KEY_STATUS).getAsString();
                        if (!jsonObject.get(KEY_MESSAGE).isJsonNull())
                            message = jsonObject.get(KEY_MESSAGE).getAsString();

                        if (status.equalsIgnoreCase("success")) {
                            if (jsonObject.get(KEY_RESULT).isJsonObject()) {
                                jsonElement = jsonObject.get(KEY_RESULT).getAsJsonObject();
                            } else if (jsonObject.get(KEY_RESULT).isJsonArray()) {
                                jsonElement = jsonObject.get(KEY_RESULT).getAsJsonArray();
                            }
                        } else {
                            throw new IOException(message);
                        }
                    }

                }

                return delegate.fromJsonTree(jsonElement);
            }
        }.nullSafe();
    }
}



The ItemTypeAdapterFactory use the Responce Result was display in Your OWN Formet.
The above class is my own class.
I have use my Selected formet.
The Response was display in my selected Formet.
Example of my formet responce :-


    "status": "1",
    "msg": "Category data found Successfull",
    "result": [
        {
            "category_id": "4",
            "category_name": "Alternative medicine",
            "photo": "http://apnadawabazar.com/admin_anytimehealthcare/data/category/main/cat_alternative_medicine.png"
        },
        {
            "category_id": "2",
            "category_name": "Carers",
            "photo": "http://apnadawabazar.com/admin_anytimehealthcare/data/category/main/cat_carers.png"
        },
        {
            "category_id": "18",
            "category_name": "child care",
            "photo": "http://apnadawabazar.com/admin_anytimehealthcare/data/category/main/cat_optition.png"
        }



After i have use my main activity.
 ViewProductNameActivity:-



 private ActivityViewProductnameBinding binding;
    public ProductNameListAdapter adapter;
    private Context mContext;
    private ArrayList<ProductNameInfo> mProductNameInfos = new ArrayList<>();

    @Override    
         protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mContext = this;
        binding = DataBindingUtil.setContentView(this, R.layout.activity_view_productname);


      RVLayoutManager.setVerticalLayoutManager(mContext,binding.rvCategoryList);
        adapter = new ProductNameListAdapter(mContext,  mProductNameInfos);
        binding.rvCategoryList.setAdapter(adapter);
        requestToGetProductCategoryList();

    }

    private void requestToGetProductCategoryList() {
        RequestBody key = RequestBody.create(MediaType.parse("text/plain"), "gguhy");
        Call<ArrayList<ProductNameInfo>> arrayListCall = RetrofitBuilder.getInstance().getRetrofit(mContext)
                .ProductData(key);

        arrayListCall.enqueue(new RetrofitCallback<ArrayList<ProductNameInfo>>(mContext) {
            @Override            
                public void onSuccess(ArrayList<ProductNameInfo> models) {

                mProductNameInfos = models;
                if ( mProductNameInfos != null &&  mProductNameInfos.size() > 0) {
                    binding.rvCategoryList.setAdapter(new ProductNameListAdapter(mContext,  mProductNameInfos));
                }
            }

            @Override            
                public void onFail(String message) {
                Log.e("@@@3@@@","Not Response......");
            }
        });
    }
}


In above class i have use LinearLayout.
But,i have use my layout class..RVLayoutManager.
RVLayoutManager:-


class RVLayoutManager {
    public static void setGridLayoutManager(Context context, RecyclerView recyclerView, int count) {
        recyclerView.setLayoutManager(new GridLayoutManager(context, count));
    }

    public static void setVerticalLayoutManager(Context context, RecyclerView recyclerView) {
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false);
        recyclerView.setLayoutManager(linearLayoutManager);
    }

    public static void setHorizaontaLayoutManager(Context context, RecyclerView recyclerView) {
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false);
        recyclerView.setLayoutManager(linearLayoutManager);
    }
}
 

In The RVLayoutManager Class i have use multiple method of layout.
so i have use any other class .
The above activity i have use the Retrofit Callback class.



RetrofitCallback:-



public abstract class RetrofitCallback<T> implements Callback<T> {
    private Context context;

    public RetrofitCallback(Context c) {
        context = c;
    }

    public abstract void onSuccess(T arg0);

    public abstract void onFail(String message);

    @Override    public void onResponse(Call<T> call, Response<T> response) {
        if (response.isSuccessful() && response.code() == 200) {
            onSuccess(response.body());
        } else {
            Log.e("@@@1@@@","Success.....");
        }
    }

    @Override    public void onFailure(Call<T> call, Throwable error) {

        Log.e("@@@2@@@","fail.....");
    }
}







Callback methods are executed using the Retrofit callback executor
onFailure(Call<T> call, Throwable t)

Invoked when a network exception occurred talking to the server or when an unexpected exception occurred creating the request or processing the response.


onResponse(Call<T> call, Response<T> respons)


Invoked for a received HTTP response.








ProductNameListAdapter:-



class ProductNameListAdapter extends RecyclerView.Adapter<ProductNameListAdapter.MyViewHolder>{

    private Context mContext;
    private ArrayList<ProductNameInfo> mProductName;


    public ProductNameListAdapter(Context context, ArrayList<ProductNameInfo> productNames) {
        mContext = context;
        mProductName = productNames;
    }



    @Override    public ProductNameListAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int type) {
        ViewProductNameBinding viewProductNameBinding = ViewProductNameBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false);
        return new MyViewHolder(viewProductNameBinding);

    }

    @Override    public void onBindViewHolder(MyViewHolder holder, final int position) {
        final ProductNameInfo productCategoryInfo = mProductName.get(position);

        holder.binding.txtCategoryName.setText(mProductName.get(position).getCategoryName());

    }

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

    }



    public static class MyViewHolder extends RecyclerView.ViewHolder {
        private final ViewProductNameBinding binding;

        public MyViewHolder(ViewProductNameBinding binding) {
            super(binding.getRoot());
            this.binding = binding;
        }
    }
}


ProductNameInfo:-



public class ProductNameInfo {


    @SerializedName("category_name")
    @Expose    private String categoryName;

    public String getCategoryName() {
        return categoryName;
    }
}



The ProductNameInfo class is POJO class;
In this case, the JSON key category_name is mapped to the class field category_name. But note that since they are the same, there is no need to include the @SerializedName annotation on the field because Gson will map it automatically for us.
The @Expose annotation indicates that the class member should be exposed for JSON serialization or deserialization.