如何阻止默认浏览器在android中打开两次url

I have a simple application to open an url from the browser. It opens the url from the browse.but when the application is again opened then the background browser does not pop up instead the browser is again opened freshly. Such that there will be multiple instances in the background.. please help me how to stop opening the url from the browser if it is running in the resent app section. I have a simple application to open an url from