Android Open Source - AndroidLocalStorage Main Fragment

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Back to project page AndroidLocalStorage.

License

The source code is released under:

Apache License

Java Source Code

package com.example.androidlocalstorage;
//from w w  w  .  ja  va 2  s  .co m
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.webkit.JavascriptInterface;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.widget.Button;

public class MainFragment extends Fragment {

  private WebView mWebview;
  private Button mButton;
  
  
  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
      Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_main, container,false);
    
    mWebview = (WebView) view.findViewById(R.id.webView);
    mButton = (Button) view.findViewById(R.id.button);
    
    init();
    
    return view;
  }


  private void init() {
    mButton.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View arg0) {
        Intent intent = new Intent(getActivity(),MainActivity.class);  
        getActivity().startActivity(intent);
        
      }
    });
    
    //load HTML File in webview
    mWebview.loadUrl("file:///android_asset/index.html");
    
    //add the JavaScriptInterface so that JavaScript is able to use LocalStorageJavaScriptInterface's methods when calling "LocalStorage"
    mWebview.addJavascriptInterface(new LocalStorageJavaScriptInterface(getActivity().getApplicationContext()), "LocalStorage");
    
    WebSettings webSettings = mWebview.getSettings();
    //enable JavaScript in webview
    webSettings.setJavaScriptEnabled(true);

    //Enable and setup JS localStorage
    webSettings.setDomStorageEnabled(true);
    //those two lines seem necessary to keep data that were stored even if the app was killed.
    webSettings.setDatabaseEnabled(true);
    webSettings.setDatabasePath(getActivity().getFilesDir().getParentFile().getPath()+"/databases/");    
  }
  
  
  /**
   * This class is used as a substitution of the local storage in Android webviews
   * 
   * @author Diane
   */
  private class LocalStorageJavaScriptInterface {
    private Context mContext;
    private LocalStorage localStorageDBHelper;
    private SQLiteDatabase database;

    LocalStorageJavaScriptInterface(Context c) {
      mContext = c;
      localStorageDBHelper = LocalStorage.getInstance(mContext);
    }

    /**
     * This method allows to get an item for the given key
     * @param key : the key to look for in the local storage
     * @return the item having the given key
     */
    @JavascriptInterface
    public String getItem(String key)
    {
      String value = null;
      if(key != null)
      {
        database = localStorageDBHelper.getReadableDatabase();
        Cursor cursor = database.query(LocalStorage.LOCALSTORAGE_TABLE_NAME,
            null, 
            LocalStorage.LOCALSTORAGE_ID + " = ?", 
            new String [] {key},null, null, null);
        if(cursor.moveToFirst())
        {
          value = cursor.getString(1);
        }
        cursor.close();
        database.close();
      }
      return value;
    }

    /**
     * set the value for the given key, or create the set of datas if the key does not exist already.
     * @param key
     * @param value
     */
    @JavascriptInterface
    public void setItem(String key,String value)
    {
      if(key != null && value != null)
      {
        String oldValue = getItem(key);
        database = localStorageDBHelper.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(LocalStorage.LOCALSTORAGE_ID, key);
        values.put(LocalStorage.LOCALSTORAGE_VALUE, value);
        if(oldValue != null)
        {
          database.update(LocalStorage.LOCALSTORAGE_TABLE_NAME, values, LocalStorage.LOCALSTORAGE_ID + "='" + key + "'", null);
        }
        else
        {
          database.insert(LocalStorage.LOCALSTORAGE_TABLE_NAME, null, values);
        }
        database.close();
      }
    }

    /**
     * removes the item corresponding to the given key
     * @param key
     */
    @JavascriptInterface
    public void removeItem(String key)
    {
      if(key != null)
      {
        database = localStorageDBHelper.getWritableDatabase();
        database.delete(LocalStorage.LOCALSTORAGE_TABLE_NAME, LocalStorage.LOCALSTORAGE_ID + "='" + key + "'", null);
        database.close();
      }
    }

    /**
     * clears all the local storage.
     */
    @JavascriptInterface
    public void clear()
    {
      database = localStorageDBHelper.getWritableDatabase();
      database.delete(LocalStorage.LOCALSTORAGE_TABLE_NAME, null, null);
      database.close();
    }
  }
}

Java Source Code List

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