Android: 可以使用此 Intent嗎? | Android Developers

public boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List list =  packageManager.queryIntentActivities(intent,
                    PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}
...
scanAvailable = isIntentAvailable(this, "com.google.zxing.client.android.SCAN");
...