AppRater.java

package de.onyxbits.sensorreadout;

import android.app.AlertDialog;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.util.Log;

/**
 * Ask the user about reviewing the app on Google Play after a reasonable
 * amount of time and launches.
 */
class AppRater implements DialogInterface.OnClickListener {

	private static final int DAYS_UNTIL_PROMPT = 7;
	private static final int LAUNCHES_UNTIL_PROMPT = 14;
	private static final String PREFSFILE = "apprater";

	private Context context;

	private AppRater(Context context) {
		this.context = context;
	}

	/**
	 * Should be called on every <code>Activity.onCreate()</code>. Checks if the
	 * trial period is over and if so brings up a notification dialog.
	 * 
	 * @param ctx
	 *          The application context.
	 */
	public static void appLaunched(Context ctx) {
		try {
			// Don't even bother if not installed from Google Play
			PackageManager pm = ctx.getPackageManager();
			String pn = ctx.getPackageName();
			String inst = pm.getInstallerPackageName(pn);
			if (inst == null || !(inst.startsWith("com.google")
					|| inst.startsWith("com.android"))) {
				return;
			}
		}
		catch (Exception exp) {
			Log.w("AppRater",exp);
			// Just bailout. Don't even try recovery.
			return;
		}

		SharedPreferences prefs = ctx.getSharedPreferences(PREFSFILE, 0);
		if (prefs.getBoolean("dontshowagain", false)) {
			return;
		}

		SharedPreferences.Editor editor = prefs.edit();

		// Increment launch counter
		long launch_count = prefs.getLong("launch_count", 0) + 1;
		editor.putLong("launch_count", launch_count);

		// Get date of first launch
		Long date_firstLaunch = prefs.getLong("date_firstlaunch", 0);
		if (date_firstLaunch == 0) {
			date_firstLaunch = System.currentTimeMillis();
			editor.putLong("date_firstlaunch", date_firstLaunch);
		}
		editor.commit();

		// Wait at least n days before opening
		if (launch_count >= LAUNCHES_UNTIL_PROMPT) {
			if (System.currentTimeMillis() >= date_firstLaunch
					+ (DAYS_UNTIL_PROMPT * 24 * 60 * 60 * 1000)) {
				showRateDialog(ctx);
			}
		}
	}

	/**
	 * Just bring up the rating dialog without checking whether or not the trial
	 * period has ended
	 * 
	 * @param ctx
	 *          application context
	 */
	public static void showRateDialog(Context ctx) {
		AppRater rater = new AppRater(ctx);
		AlertDialog.Builder builder = new AlertDialog.Builder(ctx);
		builder.setTitle(R.string.apprater_title);
		builder.setMessage(R.string.apprater_message);
		builder.setIcon(R.drawable.ic_rate);
		builder.setPositiveButton(R.string.apprater_positive, rater);
		builder.setNegativeButton(R.string.apprater_negative, rater);
		builder.setNeutralButton(R.string.apprater_neutral, rater);
		builder.create().show();
	}

	@Override
	public void onClick(DialogInterface di, int id) {
		SharedPreferences.Editor editor = context
				.getSharedPreferences(PREFSFILE, 0).edit();
		switch (id) {
			case DialogInterface.BUTTON_POSITIVE: {
				try {
					context.startActivity(new Intent(Intent.ACTION_VIEW, Uri
							.parse("market://details?id=" + context.getPackageName())));
				}
				catch (ActivityNotFoundException exp) {

				}
				// Fall through intended!
			}
			case DialogInterface.BUTTON_NEGATIVE: {
				editor.putBoolean("dontshowagain", true);
				break;
			}
			case DialogInterface.BUTTON_NEUTRAL:
			default: {
				// Did the user select "Later" because s/he does not have network access
				// right now or because s/he wants to extend the trial period? Let's
				// assume the later and reset the launch counter, as it is the less
				// pesky option.
				editor.putLong("launch_count", 0);
			}
		}
		editor.commit();
		di.dismiss();
	}
}