Troubleshooting a Fragment Instantiation Error in Android Development

Kacper Bąk
2 min readFeb 10, 2023
Photo by CHUTTERSNAP on Unsplash

While working on my own mobile app, I came across a rather unusual bug. While working on a settings activity I came across a problem such that my snippet, which had been working so far, simply stopped after restructuring. The whole app crashed as soon as I clicked on a specific button with the assigned fragment logic.

Here is a sample code, that isn’t working

    override fun onPreferenceStartFragment(
caller: PreferenceFragmentCompat,
pref: Preference
): Boolean {
// Instantiate the new Fragment
val args = pref.extras
val fragment = pref.fragment?.let {
supportFragmentManager.fragmentFactory.instantiate(
classLoader,
it

While debugging it seems that

it = com.example.exchangeabletoken.SettingsActivity$MessagesFragment

It seems like the code is trying to instantiate a fragment, but the application is crashing. This can be due to several reasons:

  1. The Fragment class being instantiated is not found or not accessible: If the class com.example.exchangeabletoken.SettingsActivity$MessagesFragment cannot be found or is not accessible, it will result in a crash.
  2. The Fragment class is not a subclass of Fragment: The class being instantiated should be a subclass of Fragment or else it will result in a crash.
  3. The Fragment class constructor is not accessible: If the class constructor of com.example.exchangeabletoken.SettingsActivity$MessagesFragment is not accessible or not public, the instantiation will result in a crash.
  4. The class loader used in the instantiate the method is not correct: The classLoader used in the instantiate the method should be a valid class loader that can load the com.example.exchangeabletoken.SettingsActivity$MessagesFragment class.
  5. Missing required arguments: If the Fragment requires arguments to be passed in its constructor, they need to be passed through the args bundle in the instantiate method.

To resolve the issue, I had to first identify the root cause of the crash, and then make the necessary changes to the code.

The problem was related to the path to the XML files, then correcting the path should resolve the issue. If the problem persists, there might be other factors causing the crash. It would be helpful to provide more information, such as the error message, stack trace, and relevant code snippets, to get a better understanding of the problem and provide a more accurate solution.

Source code: https://github.com/53jk1/ExchangeableToken

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