Regardless of whether or not you use AsyncTask, always remember these two rules about the single thread model:

1. Do not block the UI thread, and 

UI 쓰레드를 묶어 두지 말라

1. Make sure that you access the Android UI toolkit only on the UI thread.

오직 UI 쓰레드 위에서만 안드로이드 UI 툴킷을 접근한다는 것을 명심하라

AsyncTask just makes it easier to do both of these things.

AsyncTask는 단지 이런 것의 모두를 쉽게 만들어 준다.

source code of Shelves (ShelvesActivity.java and AddBookActivity.java)

 Photostream (LoginActivity.java, PhotostreamActivity.java and ViewPhotoActivity.java)


We highly recommend reading the source code of Shelves to see
how to persist tasks across configuration changes and
how to cancel them properly when the activity is destroyed.
어떻게 액티비티가 파괴될때 그것들을 적절하게 취소하는가

 private class DownloadFilesTask extends AsyncTask {     protected Long doInBackground(URL... urls) {         int count = urls.length;         long totalSize = 0;         for (int i = 0; i < count; i++) {             totalSize += Downloader.downloadFile(urls[i]);             publishProgress((int) ((i / (float) count) * 100));         }         return totalSize;     }     protected void onProgressUpdate(Integer... progress) {         setProgressPercent(progress[0]);     }     protected void onPostExecute(Long result) {         showDialog("Downloaded " + result + " bytes");     } }

new DownloadFilesTask().execute(url1, url2, url3);

Eclipse 사용법들

Touch button

.btn {
   text-indent: -9999px;
   display: block;
   width: 200px; /* 버튼 넓이 */
   height: 50px; /* 버튼 높이 */
   background: transparent url(img/button.png) no-repeat;
}
.btn:active {
   background: transparent url(img/button_press.png) no-repeat;
}

.btn { /* 위와동일 */
   text-indent: -9999px;
   display: block;
   width: 200px;
   height: 50px;
   background: transparent url(img/button.png) no-repeat;
}
.btn.active { /* :active를 .active로 수정 */
   background: transparent url(img/button_press.png) no-repeat;
}

implements OnClickListener  {



        // 방향키
        ImageView up = (ImageView)findViewById(R.id.buttonU);
        up.setOnClickListener(this);
        ImageView dn = (ImageView)findViewById(R.id.buttonD);
        dn.setOnClickListener(this);
        ImageView left = (ImageView)findViewById(R.id.buttonL);
        left.setOnClickListener(this);
        ImageView right = (ImageView)findViewById(R.id.buttonR);
        right.setOnClickListener(this);


	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		if ( mSnakeView.getMode() !=SnakeView.RUNNING ) return;
		switch( v.getId() )
		{
		case R.id.buttonL:
			Log.d(ICICLE_KEY,"onClick : R.id.buttonL"  );
			
            if (mSnakeView.getDirection()!= SnakeView.EAST) {
            	mSnakeView.setmNextDirection( SnakeView.WEST );
            }
            
			break;
		case R.id.buttonR:
			Log.d(ICICLE_KEY,"onClick : R.id.buttonR"  );
			
            if (mSnakeView.getDirection()!= SnakeView.WEST) {
            	mSnakeView.setmNextDirection( SnakeView.EAST );
            }
            
			break;

		case R.id.buttonU:
			Log.d(ICICLE_KEY,"onClick : R.id.buttonU"  );
			
            if (mSnakeView.getDirection()!= SnakeView.SOUTH) {
            	mSnakeView.setmNextDirection( SnakeView.NORTH );
            }
  
			break;
		case R.id.buttonD:
			Log.d(ICICLE_KEY,"onClick : R.id.buttonD"  );
            if (mSnakeView.getDirection()!= SnakeView.NORTH) {
            	mSnakeView.setmNextDirection( SnakeView.SOUTH );
            }

			break;
		}
	}

	public int getMode() {
		return mMode;
	}

	public int getDirection() {
		return mDirection;
	}

	public void setDirection(int Direction) {
		this.mDirection = Direction;
	}

	public int getNextDirection() {
		return mNextDirection;
	}

	public void setmNextDirection(int NextDirection) {
		this.mNextDirection = NextDirection;
	}

public static InputStream getInputStream(String path) throws Exception {

            URL aURL = new URL(path);

            URLConnection conn = aURL.openConnection();            

            conn.connect();

            InputStream is = conn.getInputStream();
            return is;

}

java.net.UnknownHostException: Host is unresolved: www.myserver.com:80

        at java.net.Socket.connect(Socket.java:1037)

        at org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnection.<init>(HttpConnection.java:62)

        at org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnectionManager$ConnectionPool.getHttpConnection(HttpConnectionManager.java:145)

        at org.apache.harmony.luni.internal.net.www.protocol.http.HttpConnectionManager.getConnection(HttpConnectionManager.java:67)

        at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnection.getHTTPConnection(HttpURLConnection.java:821)

        at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:807)

        at DownloadService.getInputStream(DownloadService.java:496)

public static InputStream getInputStream(String path) throws Exception {

            InputStream is = new URI(path).toURL().openStream();

            return is;

}