如何使用类名而不是索引实例化片段类 [英] How to instantiate fragment class using class name instead of index

问题描述

我有两个名为 SessionTab 和 BillingTab 的片段类，而我正尝试使用

I have two fragment class named SessionTab and BillingTaband i am trying to create instance of those class using

SessionTab sessionTab = (SessionTab) getSupportFragmentManager().getFragments().get(1);

，但是有时这些类的索引被颠倒，然后导致 ClassCastException

but sometimes index for those classes are reversed and then it causes ClassCastException

我该如何通过传递类名而不是索引来获取那些片段类的实例，或者如何确保这些类的索引每次都保持不变，从而不会导致 ClassCastException

How can i get instance of those fragment class by passing class name instead of index or any way to make sure that index of those class stays the same everytime so it doesn't cause ClassCastException

推荐答案

使用以下方法之一: findFragmentById()和 findFragmentByTag()方法.

Use one of this methods : findFragmentById() and findFragmentByTag() methods.

参考文献: https://developer.android.com/reference/android/app/FragmentManager.html#findFragmentById(int)

更新:

ClassCastException .在您的情况下，您的 FragmentManager 返回的片段与 SessionTab 不同，因此将引发异常.

ClassCastException is invoked when you are not casting the appropriate classes to one another. In your case, Your FragmentManager is returning different fragment than SessionTab, so the exception is thrown.

如果使用 findFragmentById()或 findFragmentByTag()，则它将完全返回您想要的片段，并且不会引发异常.

If you use findFragmentById() or findFragmentByTag() , then it will return the fragment exactly what you want, and exception will not be thrown.

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