Android Open Source - android-asynctask-correctly Main Activity

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License

The source code is released under:

Apache License

Java Source Code

package com.demondevelopers.asynctaskcorrectly;
/*from  w w  w .j av  a  2s. c o  m*/
import java.util.Date;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.ScrollView;
import android.widget.TextView;
import com.demondevelopers.asynctaskcorrectly.R;


public class MainActivity extends Activity implements MyAsyncUpdate
{
  private MyAsyncTask mMyAsyncTask;
  private ScrollView mScroll;
  private TextView mStatus;
  
  
  @SuppressWarnings("deprecation")
  @Override
  protected void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    
    setContentView(R.layout.activity_main);
    
    findViewById(R.id.refresh).setOnClickListener(new View.OnClickListener()
    {
      @Override
      public void onClick(View v)
      {
        MainActivity.this.onMyAsyncUpdate(new Date() + ": " + "Clicked");
        if(mMyAsyncTask == null || mMyAsyncTask.getStatus() == AsyncTask.Status.FINISHED){
          mMyAsyncTask = new MyAsyncTask();
          mMyAsyncTask.setAsyncUpdate(MainActivity.this);
          mMyAsyncTask.execute();
        }
      }
    });
    
    mScroll = (ScrollView)findViewById(R.id.scroll);
    mStatus = (TextView)findViewById(R.id.status);
    
    mMyAsyncTask = (MyAsyncTask)getLastNonConfigurationInstance();
    if(mMyAsyncTask == null){
      onMyAsyncUpdate(new Date() + ": " + "Ready");
    }
  }
  
  @Override
  public void onMyAsyncUpdate(String text)
  {
    mStatus.setText(mStatus.getText() + "\n" + text);
    mScroll.post(new Runnable()
    {
      @Override
      public void run()
      {
        mScroll.fullScroll(View.FOCUS_DOWN);
      }
    });
  }
  
  @Override
  protected void onResume()
  {
    super.onResume();
    if(mMyAsyncTask != null){
      mMyAsyncTask.setAsyncUpdate(this);
    }
  }
  
  @Override
  public Object onRetainNonConfigurationInstance()
  {
    return mMyAsyncTask;
  }
  
  @Override
  protected void onPause()
  {
    super.onPause();
    if(mMyAsyncTask != null){
      mMyAsyncTask.setAsyncUpdate(null);
    }
  }
  
  
  private static class MyAsyncTask extends AsyncTask<Void, Void, Void>
  {
    private MyAsyncUpdate mAsyncUpdate;
    
    
    public void setAsyncUpdate(MyAsyncUpdate asyncUpdate)
    {
      mAsyncUpdate = asyncUpdate;
    }
    
    private void dispatchUpdate(String text)
    {
      if(mAsyncUpdate != null){
        mAsyncUpdate.onMyAsyncUpdate(text);
      }
    }
    
    @Override
    protected void onPreExecute()
    {
      dispatchUpdate(new Date() + ": " + "onPreExecute");
    }
    
    @Override
    protected Void doInBackground(Void... params)
    {
      for(int i = 0; i < 5; i++){
        try{
          Thread.sleep(1000);
        }
        catch(InterruptedException e){
          //
        }
        publishProgress();
      }
      return null;
    }
    
    @Override
    protected void onProgressUpdate(Void... values)
    {
      dispatchUpdate(new Date() + ": " + "onProgressUpdate");
    }
    
    @Override
    protected void onPostExecute(Void result)
    {
      dispatchUpdate(new Date() + ": " + "onPostExecute");
    }
  }
}


interface MyAsyncUpdate
{
  public void onMyAsyncUpdate(String text);
}

Java Source Code List

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