SearchHistory.java

package com.ideabag.playtunes.util;

import java.util.ArrayList;

import com.google.gson.Gson;
import com.ideabag.playtunes.R;

import android.content.Context;
import android.content.SharedPreferences;
import android.widget.ArrayAdapter;

public class SearchHistory {
	
	public static final String TAG = "SearchHistory";
	
	public static final int SEARCH_HISTORY_SIZE = 20;
	
	Context mContext;
	
	ArrayAdapter < String > adapter;
	
	SharedPreferences mSharedPrefs;
	
	Gson gson;
	
	public SearchHistory( Context context ) {
		
		mContext = context;
		mSharedPrefs = mContext.getSharedPreferences( mContext.getString( R.string.prefs_file ), Context.MODE_PRIVATE );
		
		gson = new Gson();
		
		loadSearchHistory();
		
	}
	
	public ArrayAdapter< String > getAdapter() {
		
		return adapter;
		
	}
	
	public void addSearchQuery( String mQuery ) {
		
		mQuery = mQuery.trim();
		
		SharedPreferences.Editor edit = mSharedPrefs.edit();
		
		String jsonArray = mSharedPrefs.getString( mContext.getString( R.string.pref_key_search_history ), "[]" );
		
		// Let's assume perfect decoding to a String array[]
		
		android.util.Log.i( TAG, "" + jsonArray );
		String[] mSearchHistory = gson.fromJson( jsonArray, String[].class );
		ArrayList< String > mSearchArray = new ArrayList< String >( mSearchHistory.length );
		
		
		for ( int i = 0, count = mSearchHistory.length; i < count; i++ ) {
			
			// Remove nulls
			if ( mSearchHistory[ i ] != null ) {
				
				mSearchArray.add( mSearchHistory[ i ] );
				
			}
			
		}
		
		
		int index = mSearchArray.indexOf( mQuery );
		
		
		if ( index >= 0 ) {
			
			String tmp = mSearchArray.remove(index);
			mSearchArray.add( 0, tmp );
			
		} else {
			
			mSearchArray.add( 0, mQuery );
			
		}
		
		edit.putString( mContext.getString( R.string.pref_key_search_history ), gson.toJson( mSearchArray.toArray() ) );
		edit.commit();
		
	}
	
	public void clearHistory() {
		
		SharedPreferences mSharedPrefs = mContext.getSharedPreferences( mContext.getString( R.string.prefs_file ), Context.MODE_PRIVATE );
		SharedPreferences.Editor edit = mSharedPrefs.edit();
		
		edit.putString( mContext.getString( R.string.pref_key_search_history ), "[]" );
		
		edit.commit();
		
	}
	
	public void destroy() {
		
		mSharedPrefs.unregisterOnSharedPreferenceChangeListener( mPreferencesChangeListener );
		
	}
	
	private void loadSearchHistory() {
		
		String searchHistoryString = mSharedPrefs.getString( mContext.getString( R.string.pref_key_search_history ), "[]" );
		
		String[] mSearchQueries = gson.fromJson( searchHistoryString, String[].class );
		
		if ( null != mSearchQueries ) {
			
			adapter = new ArrayAdapter < String >( mContext, R.layout.list_item_title, R.id.Title, mSearchQueries );
			
		}
		
	}
	
	SharedPreferences.OnSharedPreferenceChangeListener mPreferencesChangeListener = new SharedPreferences.OnSharedPreferenceChangeListener() {
		
		@Override public void onSharedPreferenceChanged( SharedPreferences sharedPreferences, String key ) {
			
			if ( key.equals( mContext.getString( R.string.pref_key_search_history ) ) ) {
				
				loadSearchHistory();
				
			}
			
		}
		
	};
	
}