WebAttempt to invoke virtual method 'OneFragment.refreshMaterial(int, int, int, int)' on a null object reference ' 我從 MainActivity 調用了片段方法，如下所示， OneFragment fragment = (OneFragment)getSupportFragmentManager().findFragmentById(R.id.container_body); fragment.refreshMaterial(); WebThen just have your MainActivity pass in a listener to the Adapter: ... Then you should add a setCallback method and call it from activity/fragment. Also you shouldn't make a callback static (it may lead to problems when you use the same adapter in many classes). You should create a field inside the ViewHolder.
Communicate Between Fragments Using ViewModel - Medium
Web如果有人建议我在编码方面哪里出错 错误消息： java.lang.NullPointerException: Attempt to invoke virtual method 'int android.content.res.TypedArray.getResourceId(int, int)' on a null object reference at android.app.ActivityThread.performLaunch. 我得到getResourceID的空指 … WebApr 29, 2024 · Basically somewhere in your code you called ( (MainActivity) getActivity ()).openGallery () while the fragment is not attached to activity, hence parent context return null. You should not assume that activity context is always available because more often than not the fragment gets detached and reattached again. You should skeletal system interaction other systems
Kotlin - Call fragment method from MainActivity - Stack Overflow
Web@RAM if you need to call the same method in more than one activity, you need to create an interface with that method name. Then implement that interface in what all activities you need the method call to be availed. Then in the click listener, check instance of your interface rather than using activity name. – Eldhose M Babu Jul 8, 2015 at 13:14 1 WebMar 18, 2013 · mFragmentFavorite in your code is a FragmentActivity which is not the same thing as a Fragment.That's why you're getting the type mismatch. Also, you should never call new on an Activity as that is not the proper way to start one.. If you want to start a new instance of mFragmentFavorite, you can do so via an Intent.. From a Fragment:. Intent … WebDec 21, 2024 · Fragment2 contains the method deselect. This method works fine, but am not able to call it from the MainActivity. To solve this I have tried using an interface, but without success. The second way is as implemented in the code provided below. I am trying to call deselect in the onOptionsItemSelected method, but it tells me that fragment2 == … skeletal system homeostatic imbalance