Google Code Blog: Save the date for Google I/O 2011

Google Code Blog: Save the date for Google I/O 2011: "Google I/O just recently came to a close, but it won’t be long before we start gearing up for next year. And we’d like to make sure it’s on..."

Non UI blocking network call / web request

Code snippet to fetche content(s) from the web without blocking the UI (runs in the background in a Thread). Once finished, it posts a Handler that is picked up by the UI as soon as possible.

It is widely used in most of commercial/production level apps

Code Snippet:-

import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import org.apache.http.util.ByteArrayBuffer;

public class Iconic extends Activity {
    private String html = "";
    private Handler mHandler;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mHandler = new Handler();
        checkUpdate.start();
    }

    private Thread checkUpdate = new Thread() {
        public void run() {
            try {
                URL updateURL = new URL("http://iconic.4feets.com/update");
                URLConnection conn = updateURL.openConnection();
                InputStream is = conn.getInputStream();
                BufferedInputStream bis = new BufferedInputStream(is);
                ByteArrayBuffer baf = new ByteArrayBuffer(50);

                int current = 0;
                while((current = bis.read()) != -1){
                    baf.append((byte)current);
                }

                /* Convert the Bytes read to a String. */
                html = new String(baf.toByteArray());
                mHandler.post(showUpdate);
            } catch (Exception e) {
            }
        }
    };

    private Runnable showUpdate = new Runnable(){
           public void run(){
            Toast.makeText(Iconic.this, "HTML Code: " + html, Toast.LENGTH_SHORT).show();
        }
    };
}

Check for Updates in background Once in two days - schedule a background updates checker

This code checks for updates of the Activity once in 2 days and in the background. If an update (higher version than current) is found, it opens a Dialog and asks the user to open the market. 

code-snippet:-

public class Test extends Activity {
    private Handler mHandler;


    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.front);
        mHandler = new Handler();
       
        /* Get Last Update Time from Preferences */
        SharedPreferences prefs = getPreferences(0);
        lastUpdateTime =  prefs.getLong("lastUpdateTime", 0);
       
        /* Should Activity Check for Updates Now? once in 2days */
        if ((lastUpdateTime + (2*24 * 60 * 60 * 1000)) < System.currentTimeMillis()) {

            /* Save current timestamp for next Check*/
            lastUpdateTime = System.currentTimeMillis();           
            SharedPreferences.Editor editor = getPreferences(0).edit();
            editor.putLong("lastUpdateTime", lastUpdateTime);
            editor.commit();       

            /* Start Update */           
            checkUpdate.start();
        }
    }
   
    /* This Thread checks for Updates in the Background */
    private Thread checkUpdate = new Thread() {
        public void run() {
            try {
                URL updateURL = new URL("http://abc.com/update");               
                URLConnection conn = updateURL.openConnection();
                InputStream is = conn.getInputStream();
                BufferedInputStream bis = new BufferedInputStream(is);
                ByteArrayBuffer baf = new ByteArrayBuffer(50);
               
                int current = 0;
                while((current = bis.read()) != -1){
                     baf.append((byte)current);
                }

                /* Convert the Bytes read to a String. */
                final String s = new String(baf.toByteArray());        
               
                /* Get current Version Number */
                int curVersion = getPackageManager().getPackageInfo("your.application.id", 0).versionCode;
                int newVersion = Integer.valueOf(s);
               
                /* Is a higher version than the current already out? */
                if (newVersion > curVersion) {
                    /* Post a Handler for the UI to pick up and open the Dialog */
                    mHandler.post(showUpdate);
                }               
            } catch (Exception e) {
            }
        }
    };

    /* This Runnable creates a Dialog and asks the user to open the Market */
    private Runnable showUpdate = new Runnable(){
           public void run(){
            new AlertDialog.Builder(Test.this)
            .setIcon(R.drawable.icon)
            .setTitle("Update Available")
            .setMessage("An update for is available!\n\nOpen Android Market and see the details?")
            .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                            /* User clicked OK so do some stuff */
                            Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("market://search?q=pname:your.application.id"));
                            startActivity(intent);
                    }
            })
            .setNegativeButton("No", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {
                            /* User clicked Cancel */
                    }
            })
            .show();
           }
    };   
}

To check if SD Card is present on android device via code

To check if SD Card is present on the device, we can use simple code

public static boolean isSdCardPresent(){

return android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);  

}