Java 如何调用不同活动上的OnOptions ItemSelected

我有一个活动在FolderActivity中使用OnOptions ItemSelected（MenuItem item）方法，我想在另一个活动（MainActivity）上调用此方法 主要活动使用CMU Sphinx-语音识别工具包。 我需要调用一些从FolderActivity到MainActivity的方法

    package com.evolution.filemanager.folders;

    import static android.widget.Toast.makeText;

    import java.io.File;
    import java.util.ArrayList;

    import android.annotation.TargetApi;
    import android.app.ActionBar;
    import android.app.Activity;
    import android.app.Fragment;
    import android.content.Intent;
    import android.content.res.Configuration;
    import android.os.Build;
    import android.os.Bundle;
    import android.support.v4.app.ActionBarDrawerToggle;
    import android.support.v4.view.GravityCompat;
    import android.support.v4.widget.DrawerLayout;
    import android.util.Log;
    import android.view.Gravity;
    import android.view.KeyEvent;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.WindowManager;
    import android.widget.AdapterView;
    import android.widget.AdapterView.OnItemClickListener;
    import android.widget.ListView;
    import android.widget.Toast;

    import com.evolution.filemanager.FileManagerApplication;
    import com.evolution.filemanager.about.AboutActivity;
    import com.evolution.filemanager.clipboard.Clipboard;
    import com.evolution.filemanager.clipboard.Clipboard.ClipboardListener;
    import com.evolution.filemanager.clipboard.ClipboardFileAdapter;
    import com.evolution.filemanager.favourites.FavouritesManager;
    import com.evolution.filemanager.favourites.FavouritesManager.FavouritesListener;
    import com.evolution.filemanager.nav_drawer.NavDrawerAdapter;
    import com.evolution.utils.FontApplicator;
    import com.evolution.utils.ListViewUtils;

    import edu.cmu.pocketsphinx.demo.R;

    public class FolderActivity extends Activity implements OnItemClickListener, ClipboardListener, FavouritesListener
    {   
        public static class FolderNotOpenException extends Exception
        {

        }

        private static final String LOG_TAG = "Main Activity";

        public static final String EXTRA_DIR = FolderFragment.EXTRA_DIR;

        DrawerLayout drawerLayout;
        ActionBarDrawerToggle actionBarDrawerToggle;
        File lastFolder=null;
        private FontApplicator fontApplicator;

        public static Activity FOLDERACTIVITY;

        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main_folder);

            setupDrawers();
            Clipboard.getInstance().addListener(this);

            FOLDERACTIVITY = this;

            fontApplicator = new FontApplicator(getApplicationContext(), "Roboto_Light.ttf").applyFont(getWindow().getDecorView());
        }

        public FontApplicator getFontApplicator()
        {
            return fontApplicator;
        }

        @Override
        protected void onDestroy()
        {
            Clipboard.getInstance().removeListener(this);
            FileManagerApplication application = (FileManagerApplication) getApplication();
            application.getFavouritesManager().removeFavouritesListener(this);
            super.onDestroy();
        }

        public void setLastFolder(File lastFolder)
        {
            this.lastFolder = lastFolder;
        }

        @Override
        protected void onPause()
        {
            if (lastFolder != null)
            {
                FileManagerApplication application = (FileManagerApplication) getApplication();
                application.getAppPreferences().setStartFolder(lastFolder).saveChanges(getApplicationContext());
                Log.d(LOG_TAG, "Saved last folder "+lastFolder.toString());
            }
            super.onPause();
        }

        public void setActionbarVisible(boolean visible)
        {
            ActionBar actionBar = getActionBar();
            if (actionBar == null) return;
            if (visible)
            {
                actionBar.show();
                setSystemBarTranslucency(false);
            }
            else
            {
                actionBar.hide();
                setSystemBarTranslucency(true);
            }
        }

        @TargetApi(Build.VERSION_CODES.KITKAT)
        protected void setSystemBarTranslucency(boolean translucent)
        {
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) return;

            if (translucent)
            {
                getWindow().setFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS, WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            }
            else
            {
                WindowManager.LayoutParams params = getWindow().getAttributes();
                params.flags &= (~WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
                getWindow().setAttributes(params);
                getWindow().clearFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
            }
        }

        public void setupDrawers()
        {
            this.drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
            actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, R.drawable.ic_drawer, R.string.open_drawer, R.string.close_drawer)
            {
                boolean actionBarShown = false;

                @Override
                public void onDrawerOpened(View drawerView)
                {
                    makeText(getApplicationContext(), "drawer open", Toast.LENGTH_SHORT).show();
                    super.onDrawerOpened(drawerView);
                    setActionbarVisible(true);
                    invalidateOptionsMenu();
                }

                @Override
                public void onDrawerClosed(View drawerView)
                {
                    makeText(getApplicationContext(), "drawer close", Toast.LENGTH_SHORT).show();

                    actionBarShown=false;
                    super.onDrawerClosed(drawerView);
                    invalidateOptionsMenu();
                }

                @Override
                public void onDrawerSlide(View drawerView, float slideOffset)
                {
                    super.onDrawerSlide(drawerView, slideOffset);
                    if (slideOffset > 0 && actionBarShown == false)
                    {
                        actionBarShown = true;
                        setActionbarVisible(true);
                    }
                    else if (slideOffset <= 0) actionBarShown = false;
                }
            };
            drawerLayout.setDrawerListener(actionBarDrawerToggle);
            drawerLayout.setDrawerShadow(R.drawable.drawer_shadow, Gravity.START);
            drawerLayout.setFocusableInTouchMode(false);
    //      drawerLayout.setDrawerShadow(R.drawable.drawer_shadow, Gravity.END);

            getActionBar().setDisplayHomeAsUpEnabled(true);
            getActionBar().setHomeButtonEnabled(true);

            setupNavDrawer();
            setupClipboardDrawer();
        }

        @Override
        public void onBackPressed()
        {
            if (drawerLayout.isDrawerOpen(GravityCompat.START))
                drawerLayout.closeDrawer(GravityCompat.START);
            else if (drawerLayout.isDrawerOpen(GravityCompat.END))
                drawerLayout.closeDrawer(GravityCompat.END);
            else
                super.onBackPressed();
        }

        void setupNavDrawer()
        {
            FileManagerApplication application = (FileManagerApplication) getApplication();

            // add listview header to push items below the actionbar
            ListView navListView = (ListView) findViewById(R.id.listNavigation);
            ListViewUtils.addListViewPadding(navListView, this, true);

            loadFavourites(application.getFavouritesManager());
            application.getFavouritesManager().addFavouritesListener(this);
        }

        void setupClipboardDrawer()
        {
            // add listview header to push items below the actionbar
            ListView clipboardListView = (ListView) findViewById(R.id.listClipboard);
            ListViewUtils.addListViewHeader(clipboardListView, this);
            onClipboardContentsChange(Clipboard.getInstance());
        }

        void loadFavourites(FavouritesManager favouritesManager)
        {
            ListView listNavigation = (ListView) findViewById(R.id.listNavigation);
            NavDrawerAdapter navDrawerAdapter = new NavDrawerAdapter(this, new ArrayList<NavDrawerAdapter.NavDrawerItem>(favouritesManager.getFolders()));
            navDrawerAdapter.setFontApplicator(fontApplicator);
            listNavigation.setAdapter(navDrawerAdapter);
            listNavigation.setOnItemClickListener(this);
        }

        @Override
        protected void onPostCreate(Bundle savedInstanceState)
        {
            super.onPostCreate(savedInstanceState);
            actionBarDrawerToggle.syncState();

            if (getFragmentManager().findFragmentById(R.id.fragment) == null)
            {
                FolderFragment folderFragment = new FolderFragment();
                if (getIntent().hasExtra(EXTRA_DIR))
                {
                    Bundle args = new Bundle();
                    args.putString(FolderFragment.EXTRA_DIR, getIntent().getStringExtra(EXTRA_DIR));
                    folderFragment.setArguments(args);
                }

                getFragmentManager()
                    .beginTransaction()
                    .replace(R.id.fragment, folderFragment)
                    .commit();
            }
        }

        @Override
        public void onConfigurationChanged(Configuration newConfig)
        {
            makeText(getApplicationContext(), "unsa ni?", Toast.LENGTH_SHORT).show();

            super.onConfigurationChanged(newConfig);
            actionBarDrawerToggle.onConfigurationChanged(newConfig);
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item)
        {

            makeText(getApplicationContext(), item.toString(), Toast.LENGTH_SHORT).show();
            if (actionBarDrawerToggle.onOptionsItemSelected(item))
                return true;
            switch (item.getItemId())
            {
                case R.id.menu_about:
                    startActivity(new Intent(getApplicationContext(), AboutActivity.class));
                    return true;
            }
            return super.onOptionsItemSelected(item);
        }

        public void showFragment(Fragment fragment)
        {
            getFragmentManager()
                .beginTransaction()
                .addToBackStack(null)
                .replace(R.id.fragment, fragment)
                .commit();
        }

        public void goBack()
        {
            getFragmentManager().popBackStack();

        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu)
        {
            getMenuInflater().inflate(R.menu.main, menu);
            return true;
        }

        public FolderFragment getFolderFragment()
        {
            Fragment fragment = getFragmentManager().findFragmentById(R.id.fragment);
            if (fragment instanceof FolderFragment)
                return (FolderFragment) fragment;
            else return null;

        }

        public File getCurrentFolder() throws FolderNotOpenException
        {
            FolderFragment folderFragment = getFolderFragment();
            if (folderFragment == null)
                throw new FolderNotOpenException();
            else return folderFragment.currentDir;
        }

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3)
        {
            switch (arg0.getId())
            {
                case R.id.listNavigation:
                    NavDrawerAdapter.NavDrawerItem item = (NavDrawerAdapter.NavDrawerItem) arg0.getItemAtPosition(arg2);
                    if (item.onClicked(this))
                        drawerLayout.closeDrawers();
                    break;

                case R.id.listClipboard:
                    FolderFragment folderFragment = getFolderFragment();
                    if (folderFragment != null)
                    {
                        // TODO: paste single file
                    }
                    break;

                default:
                    break;
            }
        }

        public File getLastFolder()
        {
            return lastFolder;
        }

        @Override
        public void onClipboardContentsChange(Clipboard clipboard)
        {
            invalidateOptionsMenu();

            ListView clipboardListView = (ListView) findViewById(R.id.listClipboard);

            if (clipboard.isEmpty() && drawerLayout != null)
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED, Gravity.END);
            else 
            {
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED, Gravity.END);
                FileManagerApplication application = (FileManagerApplication) getApplication();
                if (clipboardListView != null)
                {
                    ClipboardFileAdapter clipboardFileAdapter = new ClipboardFileAdapter(this, clipboard, application.getFileIconResolver());
                    clipboardFileAdapter.setFontApplicator(fontApplicator);
                    clipboardListView.setAdapter(clipboardFileAdapter);
                }
            }
        }

        @Override
        public void onFavouritesChanged(FavouritesManager favouritesManager)
        {
            loadFavourites(favouritesManager);
        }

        @Override
        public boolean onKeyLongPress(int keyCode, KeyEvent event)
        {
            Log.d("Key Long Press", event.toString());
            if (keyCode == KeyEvent.KEYCODE_BACK)
            {
                finish();
                return true;
            }
            else return super.onKeyLongPress(keyCode, event);
        }

    }

package com.evolution.filemanager.folders；
导入静态android.widget.Toast.makeText；
导入java.io.File；
导入java.util.ArrayList；
导入android.annotation.TargetApi；
导入android.app.ActionBar；
导入android.app.Activity；
导入android.app.Fragment；
导入android.content.Intent；
导入android.content.res.Configuration；
导入android.os.Build；
导入android.os.Bundle；
导入android.support.v4.app.ActionBarDrawerToggle；
导入android.support.v4.view.GravityCompat；
导入android.support.v4.widget.DrawerLayout；
导入android.util.Log；
导入android.view.Gravity；
导入android.view.KeyEvent；
导入android.view.Menu；
导入android.view.MenuItem；
导入android.view.view；
导入android.view.WindowManager；
导入android.widget.AdapterView；
导入android.widget.AdapterView.OnItemClickListener；
导入android.widget.ListView；
导入android.widget.Toast；
导入com.evolution.filemanager.filemanager应用程序；
导入com.evolution.filemanager.about.AboutActivity；
导入com.evolution.filemanager.clipboard.clipboard；
导入com.evolution.filemanager.clipboard.ClipboardListener；
导入com.evolution.filemanager.ClipboardFileAdapter；
导入com.evolution.filemanager.favorites.favoritesmanager；
导入com.evolution.filemanager.favorites.favoritesmanager.favoritesListener；
导入com.evolution.filemanager.nav_drawer.NavDrawerAdapter；
导入com.evolution.utils.FontApplicator；
导入com.evolution.utils.ListViewUtils；
导入edu.cmu.pocketsphinx.demo.R；
公共类FolderActivity扩展活动实现了McClickListener、ClipboardListener、FavoriteSListener
{   
公共静态类FolderNotOpenException扩展异常
{
}
私有静态最终字符串日志\u TAG=“主活动”；
公共静态最终字符串EXTRA_DIR=FolderFragment.EXTRA_DIR；
抽屉布局抽屉布局；
ActionBarDrawerToggle ActionBarDrawerToggle；
文件lastFolder=null；
私人喷泉喷头喷泉喷头；
公共静态活动民俗活动；
创建时受保护的void（Bundle savedInstanceState）
{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u主文件夹）；
设置抽屉（）；
Clipboard.getInstance（）.addListener（此）；
FOLDERACTIVITY=这一点；
fontApplicator=新fontApplicator（getApplicationContext（），“Roboto_Light.ttf”）.applyFont（getWindow（）.getDecorView（））；
}
公共FontApplicator getFontApplicator（）
{
返回式治疗头；
}
@凌驾
受保护的空onDestroy（）
{
Clipboard.getInstance（）.removeListener（此）；
FileManagerApplication=（FileManagerApplication）getApplication（）；
application.GetFavoriteSManager（）.RemoveFavoriteSListener（此）；
super.ondestory（）；
}
公用void setLastFolder（文件lastFolder）
{
this.lastFolder=lastFolder；
}
@凌驾
受保护的void onPause（）
{
如果（lastFolder！=null）
{
FileManagerApplication=（FileManagerApplication）getApplication（）；
application.getAppPreferences（）.setStartFolder（lastFolder）.saveChanges（getApplicationContext（））；
Log.d（Log_标记，“保存的最后一个文件夹”+lastFolder.toString（））；
}
super.onPause（）；
}
public void setActionbarVisible（布尔可见）
{
ActionBar ActionBar=getActionBar（）；
if（actionBar==null）返回；
如果（可见）
{
actionBar.show（）；
设置半透明性（假）；
}
其他的
{
actionBar.hide（）；
设置半透明性（真）；
}
}
@TargetApi（Build.VERSION\u code.KITKAT）
受保护的空心半透明（布尔半透明）
{
if（Build.VERSION.SDK_INT    package edu.cmu.pocketsphinx.demo;

import static android.widget.Toast.makeText;
import static edu.cmu.pocketsphinx.SpeechRecognizerSetup.defaultSetup;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.drawable.AnimationDrawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.evolution.filemanager.about.AboutActivity;
import com.evolution.filemanager.folders.FolderActivity;
import com.evolution.utils.DataClearer;

import edu.cmu.pocketsphinx.Assets;
import edu.cmu.pocketsphinx.Hypothesis;
import edu.cmu.pocketsphinx.RecognitionListener;
import edu.cmu.pocketsphinx.SpeechRecognizer;

public class MainActivity extends Activity implements
        RecognitionListener {

    public AnimationDrawable rocketAnimation;

    private static final String KWS_SEARCH = "wakeup";
    private static final String FORECAST_SEARCH = "forecast";
    private static final String DIGITS_SEARCH = "digits";
    private static final String MENU_SEARCH = "menu";
    private static final String KEYPHRASE = "frost";

    private static final String GO_BACK = "back"; 
    private static final String PREVIOUS = "previous";

    private static final String OPEN_FILE_MANAGER = "open file manager";
    private static final String OPEN_ABOUT = "open about";
    private static final String OPEN_MUSIC = "open music";
    private static final String OPEN_PICTURES = "open pictures";
    private static final String OPEN_VIDEOS = "open videos";
    private static final String SHOW_COMMANDS = "show commands";

    private static final String CLOSE_FILE_MANAGER = "close file manager";
    private static final String CLOSE_ABOUT = "close about";
    private static final String CLOSE_MUSIC = "close music";
    private static final String CLOSE_PICTURES = "close pictures";
    private static final String CLOSE_VIDEOS = "close videos";
    private static final String CLOSE_COMMANDS = "close commands";

    private static final String SHOW_DRAWER = "show drawer";
    private static final String HIDE_DRAWER = "hide drawer";

    public static boolean isOPEN_FILE_MANAGER = false;
    private static boolean isOPEN_ABOUT = false;
    private static boolean isOPEN_MUSIC = false;
    private static boolean isOPEN_PICTURES = false;
    private static boolean isOPEN_VIDEOS = false;
    private static boolean isSHOW_COMMANDS = false;
    private static boolean isSHOW_DRAWER = false;

    private static String MENU_CAPTION;

    private SpeechRecognizer recognizer;
    private HashMap<String, Integer> captions;

    @Override
    public void onCreate(Bundle state) {
        super.onCreate(state);

        // Prepare the data for UI
        captions = new HashMap<String, Integer>();
        captions.put(KWS_SEARCH, R.string.kws_caption);
        captions.put(MENU_SEARCH, R.string.menu_caption);
        captions.put(DIGITS_SEARCH, R.string.digits_caption);
        captions.put(FORECAST_SEARCH, R.string.forecast_caption);

        setContentView(R.layout.main);
        ((TextView) findViewById(R.id.caption_text))
                .setText("Preparing the recognizer");

        ImageView rocketImage = (ImageView) findViewById(R.id.imageViewAnim);
        rocketImage.setBackgroundResource(R.drawable.heart_animation);
        rocketAnimation = (AnimationDrawable) rocketImage.getBackground();

        // Recognizer initialization is a time-consuming and it involves IO,
        // so we execute it in async task

        new AsyncTask<Void, Void, Exception>() {
            @Override
            protected Exception doInBackground(Void... params) {
                try {
                    Assets assets = new Assets(PocketSphinxActivity.this);
                    File assetDir = assets.syncAssets();
                    setupRecognizer(assetDir);
                } catch (IOException e) {
                    return e;
                }
                return null;
            }

            @Override
            protected void onPostExecute(Exception result) {
                if (result != null) {
                    ((TextView) findViewById(R.id.caption_text))
                            .setText("Failed to init recognizer " + result);
                } else {
                    switchSearch(KWS_SEARCH);
                }
            }
        }.execute();
    }

    @Override
    public void onPartialResult(Hypothesis hypothesis) {
        String text = hypothesis.getHypstr();
        TextView tv = ((TextView) findViewById(R.id.caption_text));

        if (text.equals(KEYPHRASE))
        {
            switchSearch(MENU_SEARCH);
            rocketAnimation.start();
        }
        else if (text.equals(OPEN_FILE_MANAGER))
        {
            switchSearch(KWS_SEARCH);
            Intent intent = new Intent (PocketSphinxActivity.this , FolderActivity.class);
            startActivity(intent);
            isOPEN_FILE_MANAGER = true;

        }
        else if (text.equals(CLOSE_FILE_MANAGER))
        {
            if(isOPEN_FILE_MANAGER == true)
            {
                switchSearch(KWS_SEARCH);
                FolderActivity.FOLDERACTIVITY.finish();
                isOPEN_FILE_MANAGER = false;
            }
        }
        else if (text.equals(SHOW_COMMANDS))
        {
            switchSearch(KWS_SEARCH);
            Intent intent = new Intent (PocketSphinxActivity.this , Commands.class);
            startActivity(intent);
            isSHOW_COMMANDS = true;

        }
        else if (text.equals(CLOSE_COMMANDS))
        {
            if(isSHOW_COMMANDS == true)
            {
                switchSearch(KWS_SEARCH);
                Commands.SHOWCOMMANDS.finish();
            }
        }
        else if (text.equals(OPEN_PICTURES))
        {
            switchSearch(KWS_SEARCH);
            Intent intent = new Intent (PocketSphinxActivity.this , AboutActivity.class);
            startActivity(intent);

        }
        else if(text.equals(OPEN_ABOUT))
        {
            switchSearch(KWS_SEARCH);
            Intent intent = new Intent(PocketSphinxActivity.this, AboutActivity.class);
            startActivity(intent);
            isOPEN_ABOUT = true;
        }
        else if(text.equals(CLOSE_ABOUT))
        {
            if (isOPEN_ABOUT == true)
            {
                switchSearch(KWS_SEARCH);
                AboutActivity.ABOUTACTIVITY.finish();
            }
        }

        else if(text.equals(GO_BACK) || text.equals(PREVIOUS))
        {
            if(isOPEN_FILE_MANAGER == true )
            {
                FolderActivity.FOLDERACTIVITY//where i want to call onOptionsItemSelected
                switchSearch(KWS_SEARCH);
            }

        }
        else
        {
            switchSearch(KWS_SEARCH);
            ((TextView) findViewById(R.id.result_text)).setText(text);
        }
    }

    @Override
    public void onResult(Hypothesis hypothesis) {
        ((TextView) findViewById(R.id.result_text)).setText("");
        if (hypothesis != null) {
            String text = hypothesis.getHypstr();
            makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onBeginningOfSpeech() {
    }

    @Override
    public void onEndOfSpeech() {
        if (DIGITS_SEARCH.equals(recognizer.getSearchName())
                || FORECAST_SEARCH.equals(recognizer.getSearchName())
                || OPEN_FILE_MANAGER.equals(recognizer.getSearchName()))
            switchSearch(KWS_SEARCH);
    }

    private void switchSearch(String searchName) {
        recognizer.stop();
        recognizer.startListening(searchName);
        String caption = getResources().getString(captions.get(searchName));
        ((TextView) findViewById(R.id.caption_text)).setText(caption);
    }

    private void setupRecognizer(File assetsDir) {
        File modelsDir = new File(assetsDir, "models");
        recognizer = defaultSetup()
                .setAcousticModel(new File(modelsDir, "hmm/en-us-semi"))
                .setDictionary(new File(modelsDir, "dict/cmu07a.dic"))
                .setRawLogDir(assetsDir).setKeywordThreshold(1e-20f)
                .getRecognizer();
        recognizer.addListener(this);

        // Create keyword-activation search.
        recognizer.addKeyphraseSearch(KWS_SEARCH, KEYPHRASE);
        // Create grammar-based searches.
        File menuGrammar = new File(modelsDir, "grammar/menu.gram");
        recognizer.addGrammarSearch(MENU_SEARCH, menuGrammar);
        File digitsGrammar = new File(modelsDir, "grammar/digits.gram");
        recognizer.addGrammarSearch(DIGITS_SEARCH, digitsGrammar);
        // Create language model search.
        File languageModel = new File(modelsDir, "lm/weather.dmp");
        recognizer.addNgramSearch(FORECAST_SEARCH, languageModel);
    }


    @Override
    protected void onStop(){
       super.onStop();
    }

    //Fires after the OnStop() state
    @Override
    protected void onDestroy() {
       super.onDestroy();
       try {
          trimCache(this); //clear cache to minimize the app size
          DataClearer.getInstance().clearApplicationData();
       } catch (Exception e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
       }
    }

    public static void trimCache(Context context) {
       try {
          File dir = context.getCacheDir();
          if (dir != null && dir.isDirectory()) {
             deleteDir(dir);
          }
       } catch (Exception e) {
          // TODO: handle exception
       }
    }

    public static boolean deleteDir(File dir) {
       if (dir != null && dir.isDirectory()) {
          String[] children = dir.list();
          for (int i = 0; i < children.length; i++) {
             boolean success = deleteDir(new File(dir, children[i]));
             if (!success) {
                return false;
             }
          }
       }

       // The directory is now empty so delete it
       return dir.delete();
    }

}