[ Android ] : save an array to SharedPreferences

save array to SharedPreferences :

public boolean saveArray(String[] array, String arrayName, Context mContext) {  

    SharedPreferences prefs = mContext.getSharedPreferences("preferencename", 0); 

    SharedPreferences.Editor editor = prefs.edit(); 

    editor.putInt(arrayName +"_size", array.length); 

    for(int i=0;i<array.length;i++) 

        editor.putString(arrayName + "_" + i, array[i]); 

    return editor.commit(); 

}

load array from SharedPreferences :

public String[] loadArray(String arrayName, Context mContext) { 

    SharedPreferences prefs = mContext.getSharedPreferences("preferencename", 0); 

    int size = prefs.getInt(arrayName + "_size", 0); 

    String array[] = new String[size]; 

    for(int i=0;i<size;i++) 

        array[i] = prefs.getString(arrayName + "_" + i, null); 

    return array; 

}  

[ Java ] : Read text file to string

source code :

    public String readFileAsString(String filePath) throws java.io.IOException

    {

        BufferedReader reader = new BufferedReader(new FileReader(filePath));

        String line, results = "";

        while( ( line = reader.readLine() ) != null)

        {

            results += line;

        }

        reader.close();

        return results;

    }

[ Android ] : Static Way to get Context

public class MyApplication extends Application{

    private static Context context;

    public void onCreate(){

        super.onCreate();

        MyApplication.context = getApplicationContext();

    }

    public static Context getAppContext() {

        return MyApplication.context;

    }

}

then just call  MyApplication.getAppContext(); to get context

[ Java ] : check if file exist

code:

    public boolean isFileExist(String path) {

        File file = new File(path);

        if (!file.exists()) {

            return false;

        } else {

            return true;

        }

    }

[ Android ] : Download a file & showing the progress

There are several ways to achieve this goal,

One simplest way I tried & succeed below is to use DownloadManager class (GingerBread and newer only):

1. check if download manager is available:

    /**

     * @param context used to check the device version and DownloadManager                     information

     * @return true if the download manager is available

     */

    public static boolean isDownloadManagerAvailable(Context context) {

        try {

            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.GINGERBREAD) {

                return false;

            }

            Intent intent = new Intent(Intent.ACTION_MAIN);

            intent.addCategory(Intent.CATEGORY_LAUNCHER);

            intent.setClassName("com.android.providers.downloads.ui",                                "com.android.providers.downloads.ui.DownloadList");

            List<ResolveInfo> list =                                                             context.getPackageManager().queryIntentActivities(intent,

                PackageManager.MATCH_DEFAULT_ONLY);

            return list.size() > 0;

        } catch (Exception e) {

            return false;

        }

    }

2. if step 1 checked OK, download from some URL:

String url = "some url path";

DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));

request.setDescription("to /sdcard/download");

request.setTitle("some string");

// in order for this if to run, you must use the android 3.2 to compile your app

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {

    request.allowScanningByMediaScanner();

    request.setNotificationVisibility(DownloadManager.Request.

                          VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

}

request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "some string");

// get download service and enqueue file

DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);

manager.enqueue(request);

[ Android ] : take a screenshot ( 4.0, Ice Cream Sandwich, or latter)

At Android 4.0 or later, this is easy.

Just press and hold the Volume Down and Power buttons at the same time.

[ Android ] : customize your Application icon

1. get the icon you want to use in your App, in this example:

2. visit Android Asset Studio : http://android-ui-utils.googlecode.com/hg/asset-studio/dist/index.html

click "Launcher icons" to go to page below.

3. download .zip to your local, then extract to your project, remember refresh your project, it's all done.