android查询指定的程序是否安装上 查询安装包

public staticboolean isIntentAvailable(Context
context,String action){

final PackageManager packageManager= context.getPackageManager();

final Intent intent=newIntent(action);

List<ResolveInfo> list=

packageManager.queryIntentActivities(intent,

PackageManager.MATCH_DEFAULT_ONLY);

return list.size()>0;

}

@Override

public boolean onPrepareOptionsMenu(Menu menu){

final boolean scanAvailable= isIntentAvailable(this,

"com.google.zxing.client.android.SCAN");

MenuItem item;

item = menu.findItem(R.id.menu_item_add);

item.setEnabled(scanAvailable);

return super.onPrepareOptionsMenu(menu);

}