Dicts

Android app that shows results from several search providers.

Check out the server repo for more information.

Demo (gifs might take some time to load)

Download

App is available on Google Play Store, but you are welcome to download the source code and use it as you please.

Modify the Dictionaries (Search Providers)

The app comes with some default dictionaries (which are called Search Providers). If you wish to add your own search providers or remove the default ones, there are several steps to complete.

Add a Dictionary

We will now demonstrate how to add a new search provider to the app. For this practice, we will add Wikipedia.

Note that there are few superclasses that you will extend in order to add a provider. Those superclasses will take care of most of the app's functionality (e.g. showing "no results" card when no results are available. or showing "server error" card with a retry button when an error occurs). You could override any of the superclass' methods if you want to achieve more complex behavior. In such case, the code is documented and you are advised to go through it.

1. First, make sure that your server (see server repo) supports your search provider (see add search provider)

2. Go to ApiConsts class under ApiClients package, and add the following String:

      public static final String DICTIONARY_WIKIPEDIA = "Wikipedia";

   The String holds the display name of the search provider.

   And then add that String to the array SEARCH_PROVIDERS:

      public static final String[] SEARCH_PROVIDERS = {
              DICTIONARY_WIKIPEDIA
      };

   This array defines what search providers are available.

3. Go to ClientFactory class under ApiClients package, and add the following code:

      interface Client {
          @GET("/dic/wikipedia")
          Call<ResponseBody> getWikipediaDefinitions(@Query("t") String term);
      }

   This code defines a Retrofit client.

   Now, we will add that call to our Client factory:

    public static Call<ResponseBody> getCall(Bundle queryBundle, String searchProvider, String url) {
      switch (searchProvider) {
        case ApiConsts.DICTIONARY_WIKIPEDIA:
          return getClient(url).getWikipediaDefinitions(queryBundle.getString(ApiConsts.QUERY_BUNDLE_TERM));
          // ...rest of calls and default call...
      }
    }

4. Now, we will create Java objects that wrap our json response from the server.

   You can use jsonschema2pojo to generate the appropriate java objects.

   Place the objects under SearchProviders package.

   This objects extends a base class called Results:

      public class WikipediaResults extends Results {
          @SerializedName("title")
          @Expose
          private String title;
   
          @SerializedName("extract")
          @Expose
          private String extract;
   
          public WikipediaResults(int error, String title, String extract) {
              super(error);
              this.title = title;
              this.extract = extract;
          }
   
          public String getTitle() {
              return title;
          }
   
          public void setTitle(String title) {
              this.title = title;
          }
   
          public String getExtract() {
              return extract;
          }
   
          public void setExtract(String extract) {
              this.extract = extract;
          }
   
          @Override
          public int getCount() {
              return (getTitle().equals("")) ? 0 : 1;
          }
      }

   There are 2 important things to notice:

   • On the constructor WikipediaResults, the parameter error must be set by the super class constructor: super(error).
   • You must override the method getCount() which tells us how many results are available. In our case, there is a single result if the title is not empty.

5. Now, we will create a layout for our data. This layout will be shown inside the results cards. Under res/layout create an xml layout file called definition_wikipedia.xml:

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        xmlns:tools="http://schemas.android.com/tools"
        android:padding="25dp"
        android:orientation="vertical">
   
            <android.support.v7.widget.AppCompatTextView
                style="@android:style/TextAppearance.Holo.Large"
                android:id="@+id/textViewWikipediaTitle"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textStyle="bold"
                android:textSize="30sp"
                android:textIsSelectable="false"
                android:layout_marginEnd="@dimen/dictionary_icon_size"
                tools:text="title" />
   
        <android.support.v7.widget.AppCompatTextView
            style="@android:style/TextAppearance.Holo.Large"
            android:id="@+id/textViewWikipediaExtract"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textStyle="bold"
            android:textSize="20sp"
            android:textIsSelectable="false"
            android:layout_marginEnd="@dimen/dictionary_icon_size"
            tools:text="extract" />
   
    </LinearLayout>

   This layout consist of 2 TextView views which hold the title and the extract (definition) of the search result. It looks like that:

6. Now, we will create an adapter under Adapters package that is called WikipediaTermAdapter. This adapter is a subclass of TermAdapter. The superclass will take care of most of the hard work.

    public class WikipediaTermAdapter extends TermAdapter {
   
        public class MyViewHolder extends TermAdapterViewHolder {
            public TextView title;
            public TextView extract;
   
   
            public MyViewHolder(View view) {
                super(view);
                title = (TextView) view.findViewById(R.id.textViewWikipediaTitle);
                extract = (TextView) view.findViewById(R.id.textViewWikipediaExtract);
   
            }
        }
        public WikipediaTermAdapter(Context mContext, int error, ResponseBody responseBody, View.OnClickListener retryOnClickListener) {
            super(mContext, error, responseBody, retryOnClickListener);
        }
   
        @Override
        public InnerTermViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            InnerTermViewHolder innerTermViewHolder = super.onCreateViewHolder(parent, viewType);
            innerTermViewHolder.outerTermAdapter = new MyViewHolder(innerTermViewHolder.view);
            return innerTermViewHolder;
   
        }
   
        @Override
        public void setDefinitionLayout(InnerTermViewHolder oldHolder, int position) {
   
            WikipediaResults term = ((WikipediaResults) results);
            MyViewHolder holder = ((MyViewHolder)oldHolder.outerTermAdapter);
   
            holder.title.setText(term.getTitle());
            holder.extract.setText(term.getExtract());
        }
   
        @Override
        protected Results createResultsObject(ResponseBody responseBody) {
            if (responseBody != null) {
                try {
                    return new Gson().fromJson(responseBody.string(), WikipediaResults.class);
                } catch (IOException ex) {
                    // do nothing
                }
            }
            return null;
        }
   
        @Override
        protected int getDefinitionLayoutId() {
            return R.layout.definition_wikipedia;
        }
   
        @Override
        protected Drawable getIconDrawable() {
            return mContext.getResources().getDrawable(R.drawable.wikipedia_480);
        }
    }

   Let's take a look at the important things in here:

   • If you've already used RecyclerView before, you may see that the MyViewHolder class is a standard ViewHolder.
   • Create a WikipediaTermAdapter constructor that calls its super class constructor.
   • Override the method InnerTermViewHolder as shown. This way, we make sure that the super class gets the correct MyViewHolder class.
   • Implement the abstract method setDefinitionLayout. This method sets the layout as you wish. Note that we take the method's parameters and downcast them to the classes we have just created. It's your responsibility to perform the correct cast.
   • Implement the abstract method createResultsObject which uses Gson to convert the json response to our java objects.
   • Implement the abstract method getDefinitionLayoutId which returns the appropriate layout id.
   • If you wish to add an icon to your card result, override the method getIconDrawable. If you won't, no icon will be shown.

7. Go to TermAdapterFactory class under Adapters package, and add the adapter we have just created to the factory:

    public static TermAdapter getTermAdapter(String searchProviderName, Context mContext, int error, ResponseBody responseBody, View.OnClickListener retryOnClickListener) {
        switch (searchProviderName) {
            case ApiConsts.DICTIONARY_WIKIPEDIA:
                return new WikipediaTermAdapter(mContext, error, responseBody, retryOnClickListener);
        }
   
        return null;
    }

   And that's it.

Remove Dictionaries

To remove search providers go to ApiConsts class under ApiClients package, and remove the unwanted providers from the array SEARCH_PROVIDERS:

      public static final String[] SEARCH_PROVIDERS = {
           DICTIONARY_IMAGES,
           // DICTIONARY_MORIFX, <- Remove this line
           // DICTIONARY_MILOG, <- Remove this line
           DICTIONARY_WIKIPEDIA,
           DICTIONARY_URBAN_DICTIONARY
      };

Now only images, wikipedia and urban dictionary are available throughout the app.

Author

Evyatar Ben-Shitrit - eviabs

License

This project is licensed under the MIT License.