Best Practice IntentService Android Example

The IntentService class provides a straightforward structure for running an operation on a single background thread. This allows it to handle long-running operations without affecting your user interface's responsiveness. Also, an IntentService isn't affected by most user interface lifecycle events, so it continues to run in circumstances that would shut down an AsyncTask.This tutorial shows Best Practice IntentService Android Example

An IntentService has a few limitations:

• It can't interact directly with your user interface. To put its results in the UI, you have to send them to an Activity.
• Work requests run sequentially. If an operation is running in an IntentService, and you send it another request, the request waits until the first operation is finished.
• An operation running on an IntentService can't be interrupted.

However, in most cases an IntentService is the preferred way to perform simple background operations.

1)Create a WorkerIntentService.java extending IntentService

package com.cretlabs.intentservice;

import android.app.IntentService;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;

/**
 * Created by Gokul on 2/25/2018.
 */

public class WorkerIntentService extends IntentService {
    private static final String TAG = "WorkerIntentService";
    public static final String RECEIVER = "receiver";
    public static final int SHOW_RESULT = 123;
    /**
     * Result receiver object to send results
     */
    private android.support.v4.os.ResultReceiver mResultReceiver;

    /**
     * Actions download
     */
    public static final String ACTION_DOWNLOAD = "action.DOWNLOAD_DATA";

    /**
     * Creates an IntentService.  Invoked by your subclass's constructor.
     *
     */
    public WorkerIntentService() {
        super(TAG);
    }



    @Override
    protected void onHandleIntent(@Nullable Intent intent) {
        if (intent.getAction() != null) {
            switch (intent.getAction()) {
                case ACTION_DOWNLOAD:
                    mResultReceiver = intent.getParcelableExtra(RECEIVER);
                    for(int i=0;i<10;i++){
                        try {
                            Thread.sleep(1000);
                            Bundle bundle = new Bundle();
                            bundle.putString("data",String.format("Showing From Intent Service %d", i));
                            mResultReceiver.send(SHOW_RESULT, bundle);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    break;
            }
        }
    }
}

 

2)Create a ResultReceiver.java to communicate to activity from background

public class ResultReceiver extends android.support.v4.os.ResultReceiver {
    private static final String TAG = "ResultReceiver";
    private Receiver mReceiver;

    /**
     * Create a new ResultReceive to receive results.  Your
     * {@link #onReceiveResult} method will be called from the thread running
     * <var>handler</var> if given, or from an arbitrary thread if null.
     *
     * @param handler the handler object
     */
    public ResultReceiver(Handler handler) {
        super(handler);
    }

    public void setReceiver(Receiver receiver) {
        mReceiver = receiver;
    }


    @Override
    protected void onReceiveResult(int resultCode, Bundle resultData) {
        if (mReceiver != null) {
            mReceiver.onReceiveResult(resultCode, resultData);
        }
    }

    public interface Receiver {
        void onReceiveResult(int resultCode, Bundle resultData);
    }
}

3)Create MainActivity.java

public class MainActivity extends AppCompatActivity implements ResultReceiver.Receiver {
    ResultReceiver mResultReceiver;
    TextView mTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mResultReceiver = new ResultReceiver(new Handler());
        mResultReceiver.setReceiver(this);
        mTextView = findViewById(R.id.tv_data);
        showDataFromBackground(MainActivity.this, mResultReceiver);
    }

    private void showDataFromBackground(Context context , ResultReceiver mResultReceiver) {
            Intent intent = new Intent( context, WorkerIntentService.class);
            intent.putExtra(RECEIVER, mResultReceiver);
            intent.setAction(ACTION_DOWNLOAD);
            startService(intent);
    }

    public void showData(String data) {
        mTextView.setText(String.format("%s\n%s", mTextView.getText(), data));
    }

    @Override
    public void onReceiveResult(int resultCode, Bundle resultData) {
        switch (resultCode) {
            case SHOW_RESULT:
                if (resultData != null) {
                    showData(resultData.getString("data"));
                }
                break;
        }
    }
}

5)Create main_activity.xml

<?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.cretlabs.intentservice.MainActivity">


    <TextView
        android:id="@+id/tv_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

Article is originally published in http://thoughtnerds.com/best-practice-intentservice-android-example/