Reputation: 123
I started learning reactive programming quite recently. I can read API JSON files using Retrofit2, but I don’t know how to do it using reactive programming using RxJava2. If you have links or ready-made code, it would be grateful. I myself tried to implement this task, but it does not work. I did everything according to this link - https://www.learn2crack.com/2017/11/retrofit-and-rxjava-in-kotlin.html, but when I call the Response function in subscribe, nothing works. For example, I try to display it, but nothing is displayed.
MainActivity class
package com.example.json_rxjava
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import com.example.json_rxjava.MODEL.JsonModel
import com.example.json_rxjava.NETWORK.RequestInterface
import io.reactivex.android.schedulers.AndroidSchedulers
import io.reactivex.disposables.CompositeDisposable
import io.reactivex.schedulers.Schedulers
import retrofit2.Retrofit
import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory
import retrofit2.converter.gson.GsonConverterFactory
class MainActivity : AppCompatActivity() {
private val BASE_URL = "https://learn2crack-json.herokuapp.com/"
private var mCompositeDisposable: CompositeDisposable? = null
private var mJsonModelDataList: ArrayList<JsonModel>? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
loadJSON()
}
private fun loadJSON() {
val requestInterface = Retrofit.Builder()
.baseUrl(BASE_URL)
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create())
.build().create(RequestInterface::class.java)
mCompositeDisposable?.add( requestInterface.getData()
.observeOn(AndroidSchedulers.mainThread())
.subscribeOn(Schedulers.io())
.subscribe(this::handleResponse)
)
}
private fun handleError(error: Throwable) {
Log.e("ERROR: ", error.localizedMessage)
}
private fun handleResponse(jsonModel: List<JsonModel>) {
Log.e("LOG TEST", "THIS IS RESPONSE")
mJsonModelDataList = ArrayList(jsonModel)
for(i in 0..mJsonModelDataList!!.size-1) {
Log.e("LOG: ", mJsonModelDataList?.get(i)?.name.toString())
}
}
override fun onDestroy() {
super.onDestroy()
mCompositeDisposable?.clear()
}
}
RequestInterface
package com.example.json_rxjava.NETWORK
import com.example.json_rxjava.MODEL.JsonModel
import io.reactivex.Observable
import retrofit2.http.GET
interface RequestInterface {
@GET("api/android")
fun getData(): Observable<List<JsonModel>>
}
JsonModel
package com.example.json_rxjava.MODEL
data class JsonModel(
val version: String,
val name: String,
val apiLevel: String
)
Added the following dependencies to build.gradle:
//RxJava and Retrofit
implementation 'com.squareup.retrofit2:retrofit:2.3.0'
implementation 'com.squareup.retrofit2:converter-gson:2.3.0'
implementation 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'
implementation 'io.reactivex.rxjava2:rxjava:2.1.6'
implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
In AndroidManifest added:
<uses-permission android:name="android.permission.INTERNET"/>
The program outputs:
D/NetworkSecurityConfig: Using Network Security Config from resource network_security_config debugBuild: true
D/: HostConnection::get() New Host Connection established 0xa3fc0140, tid 8411
D/: HostConnection::get() New Host Connection established 0xa3fc0500, tid 8460
I/OpenGLRenderer: Initialized EGL, version 1.4
D/OpenGLRenderer: Swap behavior 1
W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
D/OpenGLRenderer: Swap behavior 0
D/EGL_emulation: eglCreateContext: 0xaed85360: maj 2 min 0 rcv 2
D/EGL_emulation: eglMakeCurrent: 0xaed85360: ver 2 0 (tinfo 0xaed831f0)
D/EGL_emulation: eglMakeCurrent: 0xaed85360: ver 2 0 (tinfo 0xaed831f0)
D/EGL_emulation: eglMakeCurrent: 0xaed85360: ver 2 0 (tinfo 0xaed831f0)
Please tell me, if you know what the problem is, or if you have links or ready-made code about how to read API JSON using Retrofit2 and RxJava2 in Kotlin, then discard it please.
Upvotes: 0
Views: 253
Reputation: 1735
The reason nothing is happening is that you forgot to initialize mCompositeDisposable
. So whenever you execute mCompositeDisposable?.
, that code is skipped because mCompositeDisposable is null
.
To fix it, replace the declaration with
private val mCompositeDisposable: CompositeDisposable = CompositeDisposable()
Upvotes: 1