Determine if Android app is being used for the first time

Another idea is to use a setting in the Shared Preferences. Same general idea as checking for an empty file, but then you don't have an empty file floating around, not being used to store anything


You can use the SharedPreferences to identify if it is the "First time" the app is launched. Just use a Boolean variable ("my_first_time") and change its value to false when your task for "first time" is over.

This is my code to catch the first time you open the app:

final String PREFS_NAME = "MyPrefsFile";

SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);

if (settings.getBoolean("my_first_time", true)) {
    //the app is being launched for first time, do something        
    Log.d("Comments", "First time");

             // first time task

    // record the fact that the app has been started at least once
    settings.edit().putBoolean("my_first_time", false).commit(); 
}

I suggest to not only store a boolean flag, but the complete version code. This way you can also query at the beginning if it is the first start in a new version. You can use this information to display a "Whats new" dialog, for example.

The following code should work from any android class that "is a context" (activities, services, ...). If you prefer to have it in a separate (POJO) class, you could consider using a "static context", as described here for example.

/**
 * 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 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 = "last_app_version";

/**
 * Finds out started for the first time (ever or in the current version).<br/>
 * <br/>
 * Note: This method is <b>not idempotent</b> only the first call will
 * determine the proper result. Any subsequent calls will only return
 * {@link AppStart#NORMAL} until the app is started again. So you might want
 * to consider caching the result!
 * 
 * @return the type of app start
 */
public AppStart checkAppStart() {
    PackageInfo pInfo;
    SharedPreferences sharedPreferences = PreferenceManager
            .getDefaultSharedPreferences(this);
    AppStart appStart = AppStart.NORMAL;
    try {
        pInfo = getPackageManager().getPackageInfo(getPackageName(), 0);
        int lastVersionCode = sharedPreferences
                .getInt(LAST_APP_VERSION, -1);
        int currentVersionCode = pInfo.versionCode;
        appStart = checkAppStart(currentVersionCode, lastVersionCode);
        // Update version in preferences
        sharedPreferences.edit()
                .putInt(LAST_APP_VERSION, currentVersionCode).commit();
    } catch (NameNotFoundException e) {
        Log.w(Constants.LOG,
                "Unable to determine current app version from pacakge manager. Defenisvely 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(Constants.LOG, "Current version code (" + currentVersionCode
                + ") is less then the one recognized on last startup ("
                + lastVersionCode
                + "). Defenisvely assuming normal app start.");
        return AppStart.NORMAL;
    } else {
        return AppStart.NORMAL;
    }
}

It could be used from an activity like this:

public class MainActivity extends Activity {        
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        switch (checkAppStart()) {
        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;
        }

        // ...
    }
    // ...
}

The basic logic can be verified using this JUnit test:

public void testCheckAppStart() {
    // First start
    int oldVersion = -1;
    int newVersion = 1;
    assertEquals("Unexpected result", AppStart.FIRST_TIME,
            service.checkAppStart(newVersion, oldVersion));

    // First start this version
    oldVersion = 1;
    newVersion = 2;
    assertEquals("Unexpected result", AppStart.FIRST_TIME_VERSION,
            service.checkAppStart(newVersion, oldVersion));

    // Normal start
    oldVersion = 2;
    newVersion = 2;
    assertEquals("Unexpected result", AppStart.NORMAL,
            service.checkAppStart(newVersion, oldVersion));
}

With a bit more effort you could probably test the android related stuff (PackageManager and SharedPreferences) as well. Anyone interested in writing the test? :)

Note that the above code will only work properly if you don't mess around with your android:versionCode in AndroidManifest.xml!

Tags:

Android

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