Question

This is what i have now. It is checking to see if GoLauncher is installed and if it is, it takes it to the go launcher main screen. If its not installed it takes user to market to have it installed.

What i need though is that if it is installed already i need to pop up a alert box showing the user how to install the theme. After user hits okay then it should go to GoLaunhcer main screen

gosetting = (ImageButton) findViewById(R.id.gosetting);
    gosetting.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            try {
                Intent intent = new Intent(Intent.ACTION_MAIN);
                intent.setComponent(new ComponentName("com.gau.go.launcherex","com.jiubang.ggheart.apps.desks.diy.GoLauncher"));
                startActivity(intent);
            } 
            catch (ActivityNotFoundException e) {
                AlertDialog.Builder alert = new AlertDialog.Builder(HelperActivity.this);
                alert.setTitle("GO Not Found");
                alert.setMessage("Do you want to vist the GO Launcher Android Market page?");
                alert.setIcon(R.drawable.go_icon2);
                alert.setPositiveButton("Yes",
                 new DialogInterface.OnClickListener() {
                  public void onClick(DialogInterface dialog, int id) {
                      final Intent intent = new Intent(Intent.ACTION_VIEW).setData(Uri.parse("market://details?id=com.gau.go.launcherex"));
                      startActivity(intent);
                  }
                 });
                alert.setNegativeButton("No",
                 new DialogInterface.OnClickListener() {
                  public void onClick(DialogInterface dialog, int id) {
                      return;
                  }
                 });

                alert.show();

            } catch (Exception go) {
                go.printStackTrace();
            }
        }

    });

Added your updated code and now getting this error..
!1

Answer 1

Look at the answer to Detect an application is installed or not? That explains how to query the PackageManager to find out if your app is already installed.

EDIT: Add code

public void onClick(View v) {
    if (isAppInstalled("com.gau.go.launcherex")) {
        // Show dialog about installing the theme
        AlertDialog.Builder alert = new AlertDialog.Builder(HelperActivity.this);
        alert.setTitle("GO Theme installer");
        alert.setMessage("You need to install the theme like this...");
        alert.setIcon(R.drawable.go_icon2);
        alert.setPositiveButton("OK",
                new DialogInterface.OnClickListener() {
              public void onClick(DialogInterface dialog, int id) {
                  // Here actually start the GoLauncher
                  final Intent intent = new Intent(Intent.ACTION_MAIN);
                  intent.setComponent(new ComponentName("com.gau.go.launcherex","com.jiubang.ggheart.apps.desks.diy.GoLauncher"));
                  startActivity(intent);
              }
             });
        alert.show();
    } else {
        // Here you put up the dialog about visitng the market page
        AlertDialog.Builder alert = ...
    }
}

private boolean isAppInstalled(String uri) {
    PackageManager pm = getPackageManager();
    boolean installed = false;
    try {
       pm.getPackageInfo(uri, PackageManager.GET_ACTIVITIES);
       installed = true;
    } catch (PackageManager.NameNotFoundException e) {
       installed = false;
    }
    return installed;
}