OkHttp Simple GET Request – Coding in Flow

[embedyt] https://www.youtube.com/watch?v=oGWJ8xD2W6k[/embedyt]

In this video we will use the OkHttp library to make a simple asynchronous HTTP request, download a JSON from a URL and display it in a TextView. For this we will use OkHttp’s enqueue method which executes the network call in a background thread. To update the TextView we will then access our main thread with the runOnUiThread method.

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Links & DependenciesAndroidManifest.xmlactivity_main.xmlMainActivity.java

Dependency + instructions:

square.github.io/okhttp/

Reqres API:

reqres.in

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.codinginflow.okhttprequestexample">

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.codinginflow.okhttprequestexample.MainActivity">

    <TextView
        android:id="@+id/text_view_result"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

package com.codinginflow.okhttprequestexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.io.IOException;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class MainActivity extends AppCompatActivity {

    private TextView mTextViewResult;

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

        mTextViewResult = findViewById(R.id.text_view_result);

        OkHttpClient client = new OkHttpClient();

        String url = "https://reqres.in/api/users?page=2";

        Request request = new Request.Builder()
                .url(url)
                .build();

        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                e.printStackTrace();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if (response.isSuccessful()) {
                    final String myResponse = response.body().string();

                    MainActivity.this.runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            mTextViewResult.setText(myResponse);
                        }
                    });
                }
            }
        });
    }
}