How to notify users about an Android app update?

Question

I\'ve built an Android app which is now on Play Market. From time to time, I make updates to it, and I\'d like to let users know that a new version is available.

How

Answer 1

Found a nice solution for your problem: Let´s say you want to check for version updates manually on app start and notify your users for the new Update.

Step 1: Download android-market-api (not the .jar file, the full project!)

Step 2: After importing it to eclipse, write in your activity the following code:

MarketService ms = new MarketService(activity);
ms.level(MarketService.REVISION).checkVersion();

now, we need to modify MarketService.java, because it seems to be broken.

Step 3: rewrite callback method and add the following methods

protected void callback(String url, JSONObject jo, AjaxStatus status){      
        if(jo == null) return;
        String googlePlayversion = jo.optString("version", "0");
        String smartphone_version = "";

        PackageInfo pInfo;
        try {
            pInfo = act.getPackageManager().getPackageInfo(act.getPackageName(), 0);
            smartphone_version = pInfo.versionName;
        } catch (NameNotFoundException e) {}
        boolean new_version_avaible = compare(smartphone_version, googlePlayversion);
        if(new_version_avaible){
            showUpdateDialog(jo);
        }
    }

    private static boolean compare(String v1, String v2) {
        String s1 = normalisedVersion(v1);
        String s2 = normalisedVersion(v2);
        int cmp = s1.compareTo(s2);
        String cmpStr = cmp < 0 ? "<" : cmp > 0 ? ">" : "==";
        System.out.printf("result: "+"'%s' %s '%s'%n", v1, cmpStr, v2);
        if(cmpStr.contains("<")){
            return true;
        }
        if(cmpStr.contains(">")||cmpStr.contains("==")){
            return false;
        }
        return false;
    }

    public static String normalisedVersion(String version) {
        return normalisedVersion(version, ".", 4);
    }

    public static String normalisedVersion(String version, String sep, int maxWidth) {
        String[] split = Pattern.compile(sep, Pattern.LITERAL).split(version);
        StringBuilder sb = new StringBuilder();
        for (String s : split) {
            sb.append(String.format("%" + maxWidth + 's', s));
        }
        return sb.toString();
    }

If you want to test it, modify googlePlayversion string to a higher version than your local one.

The source comparison method I used is from How do you compare two version Strings in Java?