Four ways to update UI asynchronously on Android

As we all know, due to performance requirements, Android requires that the UI can only be updated in the UI thread. To update the UI in other threads, I have roughly summarized 4 ways. You are welcome to add corrections:

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1. Use the Handler message passing mechanism;

2. Use AsyncTask asynchronous task;

3. Use runOnUiThread(action) method;

4. Use the post(Runnabel r) method of Handler;

The following four methods are used to update a TextView.

1. Use Handler message passing mechanism

 package com.example.runonuithreadtest;
 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.widget.TextView;
 public   class MainActivity extends Activity {
 private TextView tv;
 Handler handler = new Handler()
 {
 public   void handleMessage(android.os.Message msg) {
 if (msg.what== 0x123 )
 {
 tv.setText( "Updated TextView" );
 }
 };
 };
 @Override  
 protected   void onCreate(Bundle savedInstanceState) {
 super .onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tv = (TextView) findViewById(R.id.tv);
 new MyThread().start();
 }
 class MyThread extends Thread
 {
 @Override  
 public   void run() {
 // Delay update for two seconds  
 try {
 Thread.sleep( 2000 );
   } catch (InterruptedException e) {
 // TODO Auto-generated catch block  
 e.printStackTrace();
 }
   handler.sendEmptyMessage( 0x123 );
 }
 }
 }

2. Use AsyncTask asynchronous task

• Note: The operation of updating the UI can only be performed in the onPostExecute(String result) method.

 package com.example.runonuithreadtest;
 import android.app.Activity;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.widget.TextView;
 public   class MainActivity extends Activity {
 private TextView tv;
 @Override  
 protected   void onCreate(Bundle savedInstanceState) {
 super .onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tv = (TextView) findViewById(R.id.tv);
 new Yibu().execute();
 }
 class Yibu extends AsyncTask<String, String, String>
 {
 @Override  
 protected String doInBackground(String... params) {
 try {
 Thread.sleep( 2000 );
   } catch (InterruptedException e) {
 // TODO Auto-generated catch block  
 e.printStackTrace();
 }
 return   null ;
 }
 @Override  
 protected   void onPostExecute(String result) {
 // TODO Auto-generated method stub  
 tv.setText( "Updated TextView" );
 }
 }
 }

3. Use runOnUiThread(action) method

 package com.example.runonuithreadtest;
 import android.app.Activity;
 import android.os.Bundle;
 import android.widget.TextView;
 public   class MainActivity extends Activity {
 private TextView tv;
 @Override  
 protected   void onCreate(Bundle savedInstanceState) {
 super .onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tv = (TextView) findViewById(R.id.tv);
 new MyThread().start();
 }
 class MyThread extends Thread
 {
 @Override  
 public   void run() {
   runOnUiThread( new Runnable() {
 @Override  
 public   void run() {
 // TODO Auto-generated method stub  
 try {
 // Delay update for two seconds  
 Thread.sleep( 2000 );
      } catch (InterruptedException e) {
 e.printStackTrace();
 }
 tv.setText( "Updated TextView" );
 }
 });
 }
 }
 }

4. Use Handler's post (Runnabel) method

 package com.example.runonuithreadtest;
 import android.app.Activity;
 import android.os.Bundle;
 import android.os.Handler;
 import android.widget.TextView;
 public   class MainActivity extends Activity {
 private TextView tv;
 @Override  
 protected   void onCreate(Bundle savedInstanceState) {
 super .onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  tv = (TextView) findViewById(R.id.tv);
  Handler handler = new Handler();
  handler.post( new Runnable(){
 @Override  
 public   void run() {
 try {
 // Delay update for two seconds  
 Thread.sleep( 2000 );
    } catch (InterruptedException e) {
 e.printStackTrace();
 }
 tv.setText( "Updated TextView" );
 }
 });
 }
 }