Two Buttons with same ID in different Views

Question

I'm trying to swap out Layouts in my Fragment, by setting one View invisivle and the other one visible. However I want to use the same Button in both cases, which works fine on the UI-Side of the App, but I can't get the onClick-Event in the Fragment from the button in the second View.

Here is my XML:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/id_subfragment"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:id="@+id/id_tv"
    android:gravity="center"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="30dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:textSize="20sp"
    android:text="SomeText" />

<RelativeLayout
    android:id="@+id/id_relLayout_1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@id/id_tv">

    <Button
        android:id="@+id/id_button_next"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        app:backgroundTint="@color/colorPrimaryDark"
        android:text="Button" />
</RelativeLayout>

<RelativeLayout
    android:id="@+id/id_relLayout_2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/id_tv">

    <Button
        android:id="@id/id_button_next"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        app:backgroundTint="@color/colorPrimaryDark"
        android:text="Button" />
 </RelativeLayout>
</RelativeLayout>

As you see, the buttons have the same ID, so in my Fragment-class (which implements View.onClickListener I should be able to get the onClick-Event for both of them. Code from Fragment in onCreateView:

Button button = v.findViewById(R.id.id_button_next);
button.setOnClickListener(this);

I 'change' the layouts with

v.findViewById(R.id.id_relLayout_1).setVisibility(View.GONE);
v.findViewById(R.id.id_relLayout_2).setVisibility(View.VISIBLE);

Thanks for any help!

Answer 1

findViewById returns first view with the given ID, but if I'm not wrong you should be able to reference those buttons using their parents. So instead of:

Button button = v.findViewById(R.id.id_button_next);
button.setOnClickListener(this);

you could use parent containers:

RelativeLayout parent1 = v.findViewById(R.id.id_relLayout_1)
Button buttonInParent1 = parent1.findViewById(R.id.id_button_next)
buttonInParent1.setOnClickListener(this);

RelativeLayout parent2 = v.findViewById(R.id.id_relLayout_2)
Button buttonInParent2 = parent2.findViewById(R.id.id_button_next)
buttonInParent2.setOnClickListener(this);

But I want mention that having the same ids within a single view is considered as a bad practice.