检查是否有相关程序运行 action

public static 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;
}

final boolean scanAvailable = isIntentAvailable(this,
? ? ? ? "com.google.zxing.client.android.SCAN");