williscool · December 11, 2014 01:45 · Dec 11, 2014
diff --git a/AppStart.java b/AppStart.java
@@ -0,0 +1,75 @@
+  /**
+     * Distinguishes different kinds of app starts: <li>
+     * <ul>
+     * First start ever ({@link #FIRST_TIME})
+     * </ul>
+     * <ul>
+     * First start in this version ({@link #FIRST_TIME_VERSION})
+     * </ul>
+     * <ul>
+     * Normal app start ({@link #NORMAL})
+     * </ul>
+     *
+     * @author williscool
+     * inspired by
+     * @author schnatterer
+     *
+     */
+    public enum AppStart {
+        FIRST_TIME, FIRST_TIME_VERSION, NORMAL;
+    }
+
+    /**
+     * The app version code (not the version name!) that was used on the last
+     * start of the app.
+     */
+    private static final String LAST_APP_VERSION = "1";
+
+    /**
+     * Caches the result of {@link #checkAppStart(Context context, SharedPreferences sharedPreferences)}. To allow idempotent method
+     * calls.
+     */
+    private static AppStart appStart = null;
+
+    /**
+     * Finds out started for the first time (ever or in the current version).
+     *
+     * @return the type of app start
+     */
+    public AppStart checkAppStart(Context context, SharedPreferences sharedPreferences) {
+        PackageInfo pInfo;
+
+        try {
+            pInfo = context.getPackageManager().getPackageInfo(
+                    context.getPackageName(), PackageManager.COMPONENT_ENABLED_STATE_DEFAULT);
+            int lastVersionCode = sharedPreferences.getInt(
+                    LAST_APP_VERSION, -1);
+            // String versionName = pInfo.versionName;
+            int currentVersionCode = pInfo.versionCode;
+            appStart = checkAppStart(currentVersionCode, lastVersionCode);
+
+            // Update version in preferences
+            sharedPreferences.edit()
+                    .putInt(LAST_APP_VERSION, currentVersionCode).commit(); // must use commit here or app may not update prefs in time and app will loop into walkthrough
+        } catch (PackageManager.NameNotFoundException e) {
+            Log.w(TAG,
+                    "Unable to determine current app version from package manager. Defensively assuming normal app start.");
+        }
+        return appStart;
+    }
+
+    public AppStart checkAppStart(int currentVersionCode, int lastVersionCode) {
+        if (lastVersionCode == -1) {
+            return AppStart.FIRST_TIME;
+        } else if (lastVersionCode < currentVersionCode) {
+            return AppStart.FIRST_TIME_VERSION;
+        } else if (lastVersionCode > currentVersionCode) {
+            Log.w(TAG, "Current version code (" + currentVersionCode
+                    + ") is less then the one recognized on last startup ("
+                    + lastVersionCode
+                    + "). Defensively assuming normal app start.");
+            return AppStart.NORMAL;
+        } else {
+            return AppStart.NORMAL;
+        }
+    }
diff --git a/YourActivity.java b/YourActivity.java
@@ -0,0 +1,35 @@
+public class MainActivity extends Activity {
+
+
+    private SharedPreferences sharedPreferences;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+       	// you dont actually need the context variable
+	// inside of an activity class you can pass it as this and that will work
+	// it just reads a bit better
+
+        context = this;
+        sharedPreferences = PreferenceManager
+                .getDefaultSharedPreferences(context);
+
+        switch (checkAppStart(this,sharedPreferences)) {
+        case NORMAL:
+            // We don't want to get on the user's nerves
+            break;
+        case FIRST_TIME_VERSION:
+            // TODO show what's new
+            break;
+        case FIRST_TIME:
+            // TODO show a tutorial
+            break;
+        default:
+            break;
+        }
+
+        // ...
+    }
+    // ...
+}