Crash reporting to Store Store: IllegalStateException on android.view.View $ DeclaredOnClickListener.onClick

Sorry for the long answer, but I think it is helpful for explaining how to delve into the Android platform to debug the problem.

Access to the code that throws this exception:

http://androidxref.com/6.0.1_r10/xref/frameworks/base/core/java/android/view/View.java

4452            try {
4453                mMethod.invoke(mHostView.getContext(), v);
4454            } catch (IllegalAccessException e) {
4455                throw new IllegalStateException(
4456                        "Could not execute non-public method for android:onClick", e);
4457            } catch (InvocationTargetException e) {
4458                throw new IllegalStateException(
4459                        "Could not execute method for android:onClick", e);
4460            }

      

        
        
        
      

    

Reflection and its use in click listeners

Basically what it does is call a string based method using reflection. This method is the one defined by the application developer for responding to a button click. This is usually done because you can specify the onClickListener method via XML, for example, you can say that "goDoWhatever" is called instead of "normal client". Reflection takes a string representation of this method and tries to call the method on the specified class of that name.

A reflection error occurs when the desired method does not exist, for example, if you misspelled the name, the method is private, or the parameters are different.

Note that there are two different exceptions in this case: one for a non-public method, and then another for failing to execute. I don't know why your stack trace has no IllegalStateException related message, but vendors can change this code if they want.

I suspect you have a method with the correct name, since the resolver method function throws another error if the name is incorrect:

4463        @NonNull
4464        private Method resolveMethod(@Nullable Context context, @NonNull String name) {
4465            while (context != null) {
4466                try {
4467                    if (!context.isRestricted()) {
4468                        return context.getClass().getMethod(mMethodName, View.class);
4469                    }
                ...
4485            throw new IllegalStateException("Could not find method " + mMethodName
4486                    + "(View) in a parent or ancestor Context for android:onClick "
4487                    + "attribute defined on view " + mHostView.getClass() + idText);
4488        }
4489    }

      

        
        
        
      

    

So, this leaves us with two possibilities that I can think of: the method it finds has the wrong signature, or the method it finds is static / private.

How I would like to debug this:

I am assuming that you specify a click listener in your xml node (look at "android: onClick =" in your xml files. Then search the app for all methods with the same name and make sure they take the same kind as a parameter (make sure you import "android.view.View" into the file, as importing a wrong view can cause this.) Also make sure they are not static. Also it is probably worth looking for things that are private as this can also cause problems, but seems less likely based on your stack trace.

Why this problem can be difficult to reproduce:

If you notice that the "resolveMethod" method in the android framework just returns the first method with the same name, so if it is java for the class:

class Foo{
    void bar(String s){}
    void bar(View s){}

      

        
        
        
      

    

The method signature consists of a name (for example, "bar") and a list of parameters (in this case, a list with one "View" item or a list with one "String" item).

This Android platform code may find "void bar (String s)" instead of "void bar (View s)". This can make it difficult to reproduce the error, since the order in which the detectors discover is not deterministic ( Java reflection: Is the order of the fields and methods of a class ordered? ). As such, you might find it difficult to reproduce it, since a certain device seems to be deterministically iterating through them in some way, but not necessarily in the same way as another device / implementation.

Hope this helps! Please let me know how it turns out, I'm a graduate student doing research on software defects like this one so the details are very helpful to me.