APi_RxJava_Retrofit_RecyclerView (API TYPE - QUERY)

activity_main.xml

<?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">


    <EditText android:id="@+id/inputBookName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        android:layout_margin="20dp"
        android:hint="enter book name"
        />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/inputBookName"
        android:layout_margin="05dp"

        />


</androidx.constraintlayout.widget.ConstraintLayout>

BookListAdapter.kt

package com.example.api_rxjava.adapter

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import com.bumptech.glide.Glide
import com.example.api_rxjava.R
import com.example.api_rxjava.network.VolumeInfo
import kotlinx.android.synthetic.main.recycler_list_row.view.*

//create adapter and implements three methods

class BookListAdapter: RecyclerView.Adapter<BookListAdapter.MyViewHolder>() {

    var bookListData = ArrayList<VolumeInfo>()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BookListAdapter.MyViewHolder {
    val inflater =  LayoutInflater.from(parent.context).inflate(R.layout.recycler_list_row, parent,false)
        return MyViewHolder(inflater)
    }

    override fun onBindViewHolder(holder: BookListAdapter.MyViewHolder, position: Int) {
       holder.bind(bookListData[position])
    }

    override fun getItemCount(): Int {
       return bookListData.size
    }

    class MyViewHolder(view: View): RecyclerView.ViewHolder(view) {
        val tvTitle = view.tvTitle
        val tvPublisher = view.tvPublisher
        val tvDescription = view.tvDescription
        val thumbImageView = view.thumbImageView

        fun bind(data: VolumeInfo) {
            tvTitle.text =data.volumeInfo.title
            tvPublisher.text =data.volumeInfo.publisher
            tvDescription.text =data.volumeInfo.description

            val url = data.volumeInfo?.imageLinks.smallThumbnail
            Glide.with(thumbImageView)
                .load(url)
                .circleCrop()
                .into(thumbImageView)

        }
    }
}

BookListModel.kt

package com.example.api_rxjava.network

data class BookListModel(val items: ArrayList<VolumeInfo>)
data  class VolumeInfo(val volumeInfo: BookInfo)
data class BookInfo(val title: String, val publisher: String, val description: String, val imageLinks: ImageLinks)
data class ImageLinks(val smallThumbnail:String)

build.gradle

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
    id "kotlin-android-extensions"

}

android {
    compileSdk 32
    buildToolsVersion "29.0.3"

    defaultConfig {
        applicationId "com.example.api_rxjava"
        minSdk 21
        targetSdk 32
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'


    implementation fileTree(dir: "libs", include: ["*.jar"])

    implementation 'androidx.core:core-ktx:1.3.2'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.2'
    implementation 'androidx.recyclerview:recyclerview:1.2.0-alpha06'
    implementation 'com.squareup.retrofit2:retrofit:2.9.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
    implementation 'com.github.bumptech.glide:glide:4.11.0'
    implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.9.0'

    implementation 'androidx.recyclerview:recyclerview:1.2.0'

    // for adding cardview
    implementation 'androidx.cardview:cardview:1.0.0'

    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'


    implementation 'io.reactivex.rxjava2:rxandroid:2.1.0'
    implementation 'io.reactivex.rxjava2:rxjava:2.2.0'

   
    implementation("androidx.recyclerview:recyclerview:1.2.1")
    implementation("androidx.cardview:cardview:1.0.0")

    implementation 'com.google.code.gson:gson:2.8.7'
    implementation 'com.squareup.retrofit2:retrofit:2.9.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.9.0'

    implementation("com.squareup.okhttp3:logging-interceptor:4.10.0")

    implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"
    implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.2.0"
    implementation "android.arch.lifecycle:viewmodel:1.1.0"





}

MainActivity.kt

package com.example.api_rxjava

import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.StaggeredGridLayoutManager.VERTICAL
import com.example.api_rxjava.adapter.BookListAdapter
import com.example.api_rxjava.network.BookListModel
import com.example.api_rxjava.viewmodel.MainActivityViewModel

import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

    lateinit var viewModel: MainActivityViewModel
    lateinit var bookListAdapter: BookListAdapter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)


        initSearchBox()
        initRecyclerView()
    }

    fun initSearchBox() {
        inputBookName.addTextChangedListener(object : TextWatcher{
            override fun afterTextChanged(s: Editable?) {

            }

            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {

            }

            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
                loadAPIData(s.toString())
            }
        })
    }

    fun initRecyclerView(){
        recyclerView.apply {
            layoutManager = LinearLayoutManager(this@MainActivity)
            val decoration  = DividerItemDecoration(applicationContext, VERTICAL)
            addItemDecoration(decoration)

            bookListAdapter = BookListAdapter()
            adapter =bookListAdapter
        }
    }

    //make function api call from ViewModel
    fun loadAPIData(input: String) {
        viewModel = ViewModelProvider(this).get(MainActivityViewModel::class.java)
        viewModel.getBookListObserver().observe(this, Observer<BookListModel>{
            if(it != null) {
                //update adapter...

                bookListAdapter.bookListData = it.items
                bookListAdapter.notifyDataSetChanged()
            }
            else {
                Toast.makeText(this, "Error in fetching data", Toast.LENGTH_SHORT).show()
            }
        })
        viewModel.makeApiCall(input)
    }
}

MainActivityViewModel.kt

package com.example.api_rxjava.viewmodel

import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import com.example.api_rxjava.network.BookListModel
import com.example.api_rxjava.network.RetroInstance
import com.example.api_rxjava.network.RetroService
import io.reactivex.Observer
import io.reactivex.android.schedulers.AndroidSchedulers
import io.reactivex.disposables.Disposable
import io.reactivex.schedulers.Schedulers

class MainActivityViewModel: ViewModel() {
    lateinit var bookList: MutableLiveData<BookListModel>
    init {
        bookList = MutableLiveData()
    }

    fun getBookListObserver(): MutableLiveData<BookListModel> {
        return bookList
    }

    fun makeApiCall(query: String) {

        val retroInstance  = RetroInstance.getRetroInstance().create(RetroService::class.java)
        retroInstance.getBookListFromApi(query)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(getBookListObserverRx())
    }

    private fun getBookListObserverRx():Observer<BookListModel> {
        return object :Observer<BookListModel>{
            override fun onComplete() {
                //hide progress indicator .
            }

            override fun onError(e: Throwable) {
                bookList.postValue(null)
            }

            override fun onNext(t: BookListModel) {
                bookList.postValue(t)
            }

            override fun onSubscribe(d: Disposable) {
                //start showing progress indicator.
            }
        }
    }
}

recycler_list_row.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="wrap_content"
    android:orientation="horizontal">



    <ImageView android:id="@+id/thumbImageView"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_gravity="center"
        android:layout_margin="10dp"
        />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"

        >

        <TextView android:id="@+id/tvTitle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:textStyle="bold"
            android:textColor="#000"
            android:layout_margin="10dp"
            />

        <TextView android:id="@+id/tvPublisher"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="16sp"
            android:textStyle="bold"
            android:layout_marginStart="10dp"
            />

        <TextView android:id="@+id/tvDescription"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp"
            android:textColor="@color/teal_700"
            android:maxLines="3"
            android:layout_margin="10dp"
            />


    </LinearLayout>
</LinearLayout>

RetroInstance.kt

package com.example.api_rxjava.network

import com.google.gson.Gson
import retrofit2.Retrofit
import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory
import retrofit2.converter.gson.GsonConverterFactory

class RetroInstance {

    companion object {
    val baseURL = "https://www.googleapis.com/books/v1/"

    fun getRetroInstance() : Retrofit {


        //build API
       return Retrofit.Builder()
            .baseUrl(baseURL)
            .addConverterFactory(GsonConverterFactory.create())
            .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
            .build()
    }


    }
}

RetroService.kt

package com.example.api_rxjava.network

import io.reactivex.Observable
import retrofit2.http.GET
import retrofit2.http.Query


interface RetroService {

    @GET("volumes")
    //take input from the user as Query
    fun getBookListFromApi(@Query("q") query: String): Observable<BookListModel>
}

Resources-

Video Link - https://www.youtube.com/watch?v=3-TAwhn7Bcc&list=PLv7gZsLckhudG6MDmPwdj1JQXfcDDE3Bj&index=8&ab_channel=LearningWorldz

Api Link - https://www.googleapis.com/books/v1/volumes?q=harry