How can I check if the Android Market is installed on my user's device?

How could I write a code which can tell me that android market is开发者_JAVA技巧 installed on your android phone?

There are two ways. You can use the already mentioned getPackageManager() and getApplicationInfo() (if the package is not found, a PacketManager.NameNotFoundException will be thrown - see here). Android Market's package name is com.android.vending.

However, you can also create a dummy intent for searching the market and check how it is handled. If the resulting list has at least one entry, you can be sure that Android Market is installed:

Intent market = new Intent(Intent.ACTION_VIEW, Uri.parse("market://search?q=dummy"));
PackageManager manager = getPackageManager();
List<ResolveInfo> list = manager.queryIntentActivities(mmarket, 0);

Here's what I did (assumes browser exists):

Intent market = new Intent(Intent.ACTION_VIEW).setData(Uri
        .parse("market://details?id=com.example.app"));


Intent website = new Intent(Intent.ACTION_VIEW).setData(Uri
        .parse("http://play.google.com/store/apps/details?id=com.example.app"));

try {

    startActivity(market);

} catch (ActivityNotFoundException e) {

    startActivity(website);

}