Android - Check if APP is already installed

I wanted to have a web page with a link pointing to the apk app in a market (this is poss开发者_StackOverflow社区ible), but if the app already exists on the device did not want him to redirect the market but that the app is open soon as the app on the device.

Is that possible?

thank you

There's no way to do that on a website. You can create a link to the application on Market, and if the user is on an Android device, he or she will be redirected to the Market application - from here it's possible to see if it's installed or not.

Should you want to do it in Java code, you can use @Pedro's advice with a simple check.

You can use PackageManager.getInstalledApplications and check if the app you're looking for is listed.