How to get alertdialog() when the application is minimized?

I am new at Android developement.

Currently, I am developing receiving sms kind of application, which receives the sms and displays the alertdialog() for text to speech functionality option. I do call the method for alertdialog(开发者_JS百科) in another class from Broadcastreceiver class. When the application is running, the alertdialog() appears, but after pressing the Home button, it doesn't.

So, what should I do?

Please help me.

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Consider using a Toast. If you need user interaction, consider a Notification.

Don't try to pop up a big dialog when your app is not in the foreground, that would be utterly intrusive.