open a url on click of ok button in android

String url = "https://www.murait.com/";
if (url.startsWith("https://") || url.startsWith("http://")) {
    Uri uri = Uri.parse(url);
    Intent intent = new Intent(Intent.ACTION_VIEW, uri);
    startActivity(intent);
}else{
    Toast.makeText(mContext, "Invalid Url", Toast.LENGTH_SHORT).show();
}

You have to check that the URL is valid or not. If URL is invalid application may crash so that you have to check URL is valid or not by this method.

On Button click event write this:

Uri uri = Uri.parse("http://www.google.com"); // missing 'http://' will cause crashed
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);

that open the your URL.

You can use the below method, which will take your target URL as the only input (Don't forget http://)

void GoToURL(String url){
    Uri uri = Uri.parse(url);
    Intent intent= new Intent(Intent.ACTION_VIEW,uri);
    startActivity(intent);
}

    Button imageLogo = (Button)findViewById(R.id.iv_logo);
    imageLogo.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            String url = "http://www.gobloggerslive.com";

            Intent i = new Intent(Intent.ACTION_VIEW);
            i.setData(Uri.parse(url));
            startActivity(i);
        }
    });