Android Development: Casino Strategy v2.0
June 27, 2012
The first feature I wanted to add after I published v1.0 was the ability to change between Blackjack strategy cards by swiping rather than selecting from a menu. I found an example of a View Pager that was exactly what I needed. Modifying it to fit my app was trivial. Note: since I’m developing using API 7, I needed the SDK Tools in order to get the View Pager working.
My next idea was to add a “Share” button so if the app helped users win, they could tell their friends. It turned out to be much easier than I thought and this Stack Overflow answer explains how to add a Share Intent.
That took care of Blackjack, but since the app is called Casino Strategy, I figured it needed more casino games. I started by adding a new Activity with a list of games for the user to select. I wanted this new Activity to launch on start-up and and the answer lies in intent filters.
In AndoidManifest.xml
,
<activityandroid:name=".MainActivity"android:label="@string/app_name" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity><activityandroid:name=".BlackjackActivity"android:label="@string/app_name" ></activity>
To switch to the other activities, the new src/MainActivity.java
,
public static final int BLACKJACK = 0;private final Map<Integer,Class<?>> mIntentMap = new HashMap<Integer,Class<?>>();@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);mIntentMap.put(BLACKJACK, BlackjackActivity.class);setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.games_array)));ListView lv = getListView();lv.setTextFilterEnabled(true);lv.setOnItemClickListener(new OnItemClickListener() {public void onItemClick(AdapterView<?> parent, View view,int position, long id) {Class<?> cls = mIntentMap.get(position);if (null != cls) {Intent intent = new Intent(CasinoStrategyActivity.this, cls);if (null != intent) startActivity(intent);}}});}
To populate the list adapter, I’m using a string array. With only one game it’s overkill, but it will soon make sense.
In res/values/strings.xml
,
<string-array name="games_array"><item>Blackjack</item></string-array>
My second favorite casino game is Craps so it was next. Rather than creating a fancy graphic, the optimal strategy can easily be expressed in text. Adding a new game is a few easy steps:
- Add a new Activity class to the src folder
- Register that new Activity in AndroidManifest.xml
- Add a new
<Integer, Class>
pair to the map in MainActivity.java - Add a new string to games_array
Here are some of the interesting parts:
In src/CrapsActivity
,
public class CrapsActivity extends GameActivity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.text_view);setText(R.id.text_view, R.string.craps);setText(R.id.text_view_title, R.string.craps_title);}}
In res/layout/text_view.xml
,
<TextViewandroid:id="@+id/text_view_title"android:layout_width="wrap_content"android:layout_height="wrap_content"android:textSize="22sp" /><TextViewandroid:id="@+id/text_view"android:layout_width="wrap_content"android:layout_height="wrap_content"android:textSize="18sp" />
Notice that CrapsActivity extends GameActivity instead of Activity. Since my Share Intent is used by all games, I moved it to a base class that Blackjack and Craps extend.
I added Roulette in an almost identical way as Craps.