Adding An Alert Dialog Box With A Retry Button

I am working on a project where an alert dialog box appears if there is no internet connection on the phone. This alert dialog box says that Network is Unavailable and has a button

Solution 1:

This is just one example, you should implement AlertDialog as global variable for not creating one every time you try to make the request.

public void runTask () {
    if(isNetworkAvailable())
    {
        GetBlogPostsTask getBlogPostsTask = new GetBlogPostsTask();
        getBlogPostsTask.execute();
    } else {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("ERROR !!");
        builder.setMessage("Sorry there was an error getting data from the Internet.\nNetwork Unavailable!");
        ;

        AlertDialog dialog = builder.create();
        builder.setPositiveButton("Retry", new DialogInterface.OnClickListener()
        {
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                dialog.dismiss();
                runTask();
            }
        });

        dialog.show();
        Toast.makeText(this, "Network Unavailable!", Toast.LENGTH_LONG).show();
    }
}

Solution 2:

There is a small error in TeRRo's Code. You are calling AlertDialog dialog = builder.create(); before adding Buttons so buttons are not adding up.

So I updated the code. This code will check for internet connection if internet is available, it executes whatever you want, if not, It displays Alert Dialog with two buttons.

Updated code:

    if(isNetworkAvailable()) {

    /* DO WHATEVER YOU WANT IF INTERNET IS AVAILABLE */

    } else {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setCancelable(false);
        builder.setTitle("No Internet");
        builder.setMessage("Internet is required. Please Retry.");

        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
                finish();
            }
        });

        builder.setPositiveButton("Retry", new DialogInterface.OnClickListener(){
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                dialog.dismiss();
                InitiateDownload();
            }
        });
        AlertDialog dialog = builder.create(); // calling builder.create after adding buttons
        dialog.show();
        Toast.makeText(this, "Network Unavailable!", Toast.LENGTH_LONG).show();
    }

isNetworkAvailable() is a Helper method to determine if Internet connection is available.

private boolean isNetworkAvailable() {
    ConnectivityManager connectivityManager
            = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
}

Note: builder.setCancelable(false); - so user won't able to dismiss dialog by pressing back button. Happy coding.