How to iterate through a view's elements

I've done something similar in some code I don't have with me at the moment, but from memory it should be something like this (assuming a parent view LinearLayout with an id of "layout"):

LinearLayout layout = (LinearLayout)findViewById(R.id.layout);
boolean success = formIsValid(layout);

public boolean formIsValid(LinearLayout layout) {
    for (int i = 0; i < layout.getChildCount(); i++) {
        View v = layout.getChildAt(i);
        if (v instanceof EditText) {
            //validate your EditText here
        } else if (v instanceof RadioButton) {
            //validate RadioButton
        } //etc. If it fails anywhere, just return false.
    }
    return true;
}

To apply the method by kcoppock recursively, you can change it to this:

private void loopViews(ViewGroup view) {
    for (int i = 0; i < view.getChildCount(); i++) {
        View v = view.getChildAt(i);

        if (v instanceof EditText) {
            // Do something

        } else if (v instanceof ViewGroup) {

            this.loopViews((ViewGroup) v);
        }
    }
} 

If you are writing in Kotlin, Android Jetpack's Kotlin extensions (KTX) provide extension functions for iterating over a ViewGroup's children.

myViewGroup.forEach { ... }

myViewGroup.forEachIndexed { index, view -> ... }

Just add the dependency to your app. Check the link above to get the most up-to-date version.

implementation "androidx.core:core-ktx:1.2.0"

These extensions contains hoards of useful functions otherwise chalked up as boilerplate. Worth checking out now to save time in the future!