<LinearLayout
android:id="@+id/layout_add"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">

<EditText
    android:id="@+id/editTextWeightValue"
    android:layout_width="0dp"
    android:layout_height="32dp"
    android:drawableRight="@drawable/down"
    android:background="@drawable/background_edit_text"
    android:clickable="true"
    android:layout_marginLeft="22dp"
    android:layout_marginRight="10dp"
    android:inputType="number"
    android:layout_weight="1"/>
</LinearLayout>

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

@Override
    public void onClick(View view) {

        LinearLayout linearLayout = new LinearLayout(getApplicationContext());
        linearLayout = findViewById(R.id.layout_add);
        RelativeLayout relativeLayout = findViewById(R.id.rlForAdd);

        switch (view.getId()) {

            case R.id.btnAdd:

                imageViewRemove.setVisibility(View.VISIBLE);

                linearLayoutList.add(linearLayout);

                relativeLayout.addView(linearLayoutList.get(COUNT));//добавляем новый лл из списка

                COUNT++;
                break;

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: ru.involta.cooklook, PID: 2102
                  java.lang.IllegalArgumentException: Cannot add a null child view to a ViewGroup
                      at android.view.ViewGroup.addView(ViewGroup.java:3718)
                      at android.view.ViewGroup.addView(ViewGroup.java:3700)
                      at com.example.a123.project_of_recepts.AddReceipt.onClick(AddReceipt.java:329)
                      at android.view.View.performClick(View.java:4780)
                      at android.view.View$PerformClick.run(View.java:19866)
                      at android.os.Handler.handleCallback(Handler.java:739)
                      at android.os.Handler.dispatchMessage(Handler.java:95)
                      at android.os.Looper.loop(Looper.java:135)
                      at android.app.ActivityThread.main(ActivityThread.java:5254)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at java.lang.reflect.Method.invoke(Method.java:372)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
I/Process: Sending signal. PID: 2102 SIG: 9