Find App is already installed or not..?

Question

I go through lot of link and tutorial such as Check if application is installed - Android and How to check programmatically if an application is installed or not in Android? but i didn't find exact solution of my issue. When i am trying to install a app whose launcher package is com.test.app then at time of installation i want to check this package or you can say our App is already installed or not? When i am trying to do as in above link it is showing always "installed" for me either it is installed or not. So how i will manage this.

Answer 1

This is an idea . Which i have implemented

     1. Create a Web Service which our app can pull whenever the app
        launches or based on some time limit that can check if there is new version out there.
     2. This Web service should return the latest Version of the apk file that is hosted on the
        Server along with the URI of the application file that has the new version.
     3. When your app gets the response from the Web Service, it will parse the JSON and
        check our app version to the latest version that is available
        on the server.
     4. If our app version is lower than the latest version it will prompt
        the user to start the download process.
     5. Today i manage download process by the Download Manager and day before
        yesterday I do same thing by Package Manager. I will update which mechanism is
        most optimal to download .apk file with size of more than 10MB.
     6. The download manager will notify our app using Broadcast receiver when the  download
        is complete.
     7. Upon completion of the latest version of the application file the we can  
        start the activity to install that file.

Then we can compare version by

    private static int compare(String v1, String v2) {   
        String s1 = normalisedVersion(v1);
        String s2 = normalisedVersion(v2);
        int cmp = s1.compareTo(s2);
        System.out.println("cmp int  "+cmp);

        return cmp;
       /* String cmpStr = cmp < 0 ? "<" : cmp > 0 ? ">" : "==";

        System.out.printf("'%s' %s '%s'%n", v1, cmpStr, v2);*/
    }

and then

    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();
    }