AsyncTask vs Thread Handler

AsyncTask vs Thread Handler

This post show how to implement using AsyncTask and Thread/Handler to perform the same function: doing something in background and update UI elements (ProgressBar and TextView).

This video show how it run on Android Emulator running Android N, in Multi-Window.

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AsyncTask

MainActivity.java

package com.blogspot.android_er.androidasynctask;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

 Button btnStart;
 ProgressBar progressBar;
 TextView textMsg;

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

 progressBar = (ProgressBar)findViewById(R.id.progress);
 textMsg = (TextView)findViewById(R.id.msg);

 btnStart = (Button)findViewById(R.id.start);
 btnStart.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 MyAsyncTask myAsyncTask = new MyAsyncTask(progressBar, textMsg);
 myAsyncTask.execute();
 }
 });
 }

 class MyAsyncTask extends AsyncTask<Void, Integer, Void>{

 ProgressBar pBar;
 TextView tMsg;

 public MyAsyncTask(ProgressBar pBar, TextView tMsg) {
 super();
 this.pBar = pBar;
 this.tMsg = tMsg;
 }

 @Override
 protected Void doInBackground(Void... params) {
 for(int i=0; i<=10; i++){
 try {
 Thread.sleep(1000);
 } catch (InterruptedException e) {
 e.printStackTrace();
 }

 publishProgress(i);
 }
 return null;
 }

 @Override
 protected void onProgressUpdate(Integer... values) {
 pBar.setProgress(values[0]);
 }

 @Override
 protected void onPostExecute(Void aVoid) {
 tMsg.setText("finished");
 }
 }
}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
 
 android_layout_width="match_parent"
 android_layout_height="match_parent"
 android_padding="16dp"
 android_orientation="vertical"
 tools_context="com.blogspot.android_er.androidasynctask.MainActivity">

 <TextView
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_layout_gravity="center_horizontal"
 android_autoLink="web"
 android_text="http://android-er.blogspot.com/"
 android_textStyle="bold" />

 <Button
 android_id="@+id/start"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_text="Start"/>

 <ProgressBar
 android_id="@+id/progress"
 style="?android:attr/progressBarStyleHorizontal"
 android_indeterminate="false"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_max="10"
 android_progress="0"/>
 <TextView
 android_id="@+id/msg"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"/>
</LinearLayout>

---

Thread + Handler

MainActivity.java

package com.blogspot.android_er.androidthreadhandler;

import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

import org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {

 Button btnStart;
 ProgressBar progressBar;
 TextView textMsg;

 private Handler handler = new Handler();

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

 progressBar = (ProgressBar)findViewById(R.id.progress);
 textMsg = (TextView)findViewById(R.id.msg);

 btnStart = (Button)findViewById(R.id.start);
 btnStart.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 MyThread myThread = new MyThread(progressBar, textMsg);
 myThread.start();
 }
 });
 }

 class MyThread extends Thread{

 ProgressBar pBar;
 TextView tMsg;

 public MyThread(ProgressBar pBar, TextView tMsg) {
 super();
 this.pBar = pBar;
 this.tMsg = tMsg;
 }

 @Override
 public void run() {

 for (int i = 0; i <= 10; i++) {
 try {
 Thread.sleep(1000);
 } catch (InterruptedException e) {
 e.printStackTrace();
 }

 //is accessed from within inner class, needs to be declared final
 final int finalI = i;
 handler.post(new Runnable() {
 @Override
 public void run() {
 pBar.setProgress(finalI);
 }
 });
 }

 handler.post(new Runnable() {
 @Override
 public void run() {
 tMsg.setText("finished");
 }
 });
 }
 }
}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
 
 android_layout_width="match_parent"
 android_layout_height="match_parent"
 android_padding="16dp"
 android_orientation="vertical"
 tools_context="com.blogspot.android_er.androidthreadhandler.MainActivity">

 <TextView
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_layout_gravity="center_horizontal"
 android_autoLink="web"
 android_text="http://android-er.blogspot.com/"
 android_textStyle="bold" />

 <Button
 android_id="@+id/start"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_text="Start"/>

 <ProgressBar
 android_id="@+id/progress"
 style="?android:attr/progressBarStyleHorizontal"
 android_indeterminate="false"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_max="10"
 android_progress="0"/>
 <TextView
 android_id="@+id/msg"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"/>
</LinearLayout>

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next:
- HandlerThread example

related:
- Load something from Internet using URLConnection and BufferedReader, in AsyncTask
- Load something from Internet using URLConnection and BufferedReader, in Thread


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