NestedScrollView not scrolling when adding TextViews programmatically

Question

I'm including a chess board and pieces on one of the screens in my app, and I want to add a scrollable view underneath it to show the move notation when the user makes a move. I can add the text to the view, but no matter what I try, the view will not scroll.

I've researched the trouble other users have had with this problem extensively. I've included fillViewport="true" and layout_height="wrap_content" but neither of those solutions is working for me. I've played around with the margins of the nestedscrollview to no avail, and I've been having this issue for the past couple days and still haven't figured out what I'm doing wrong.

Here's the xml file:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/chessBoardScreen"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:clickable="true"
    android:focusable="true"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".ChessBoardActivity"
    tools:showIn="@layout/app_bar_chess_board">

    <android.support.constraint.ConstraintLayout
        android:id="@+id/cl_parent"
        android:layout_width="wrap_content"
        android:layout_height="350dp"
        app:layout_constraintBottom_toTopOf="@+id/move_view"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <ImageView
            android:id="@+id/board"
            android:layout_width="wrap_content"
            android:layout_height="329dp"
            android:layout_marginTop="8dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:srcCompat="@drawable/chess_board" />

        <android.support.constraint.ConstraintLayout
            android:id="@+id/cl"
            android:layout_width="0dp"
            android:layout_height="0dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

        </android.support.constraint.ConstraintLayout>

    </android.support.constraint.ConstraintLayout>

    <android.support.v4.widget.NestedScrollView
        android:id="@+id/move_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:fillViewport="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/cl_parent">

        <android.support.constraint.ConstraintLayout
            android:id="@+id/move_list"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

        </android.support.constraint.ConstraintLayout>
    </android.support.v4.widget.NestedScrollView>

</android.support.constraint.ConstraintLayout>

And here's where I call the xml file in my application, this code is executed every time the user successfully makes a move on the chess board:

ConstraintLayout ml = findViewById(R.id.move_list);
        TextView tv = new TextView(ChessBoardActivity.this);

        float left = 34*density;
        float top;
        if(move == 'b') left += screenX/2.0;
        top = (-30+30*turns)*density;

        tv.setWidth((int)(screenX/2-34*density));
        tv.setHeight((int)(30*density));
        tv.setTranslationX(left);
        tv.setTranslationY(top);
        tv.setText(moveString);
        ml.addView(tv);

Any help figuring out this problem would be appreciated! Thank you :)

I expect the nestedscrollview to be scrollable when the textviews draw beyond the screen but within the limits of the view, but it's not scrolling at all.

Zohaib Amir · Accepted Answer · 2019-08-01T08:21:15.683

0

EDIT:
I just noticed the actual problem in the code. You are manually setting position using translation, doing so will NOT UPDATE height of parent layout that's why scrollview won't scroll. You should use LinearLayout so you don't have to calculate position and in case of two columns you can use GridLayout.

OLD ANSWER: Call scrollView.invalidate() so scrollview can adjust to changes. If it doesn't work then call invalidate() on ConstraintLayout as well. If it still doesn't work, then also call requestLayout() as well.

 ml.addView(tv);
 ml.invalidate();
 NestedScrollView scrollView = findViewById(R.id.move_view);
 scrollView.invalidate();
 scrollView.requestLayout();

edited Aug 01 '19 at 08:21

answered Aug 01 '19 at 07:59

Zohaib Amir

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I've tried that before and it didn't work, but I've changed the code since then, so I'm retesting it now... And it didn't work, sadly. – Rowan McKee Aug 01 '19 at 08:09
@RowanMcKee Ah I see now what the problem is. You are adding views to your constraintLayout by setting their position manually using translation, correct? Setting translation wouldn't change Layout's Height that's why the ScrollView won't scroll – Zohaib Amir Aug 01 '19 at 08:13
@RowanMcKee You should use LinearLayout instead of ConstraintLayout – Zohaib Amir Aug 01 '19 at 08:13
Ah, thanks. I will try that and get back to you. I want text in two columns. Is there a way to accomplish that with Linear Layout without manually setting translation? – Rowan McKee Aug 01 '19 at 08:16
@RowanMcKee for the layout `R.id.move_list` with LinearLayout, then add textview to LinearLayout, call invalidate and scrollView will work. You don't need to calculate position manually since LinearLayout will take care of it for you – Zohaib Amir Aug 01 '19 at 08:16
You can use GridLayout for 2 Columns – Zohaib Amir Aug 01 '19 at 08:16
Thank you so much for the help. Despite my research into this question, nowhere did I read that setting the position manually would not change the layout height and thus cause the scrollview not to scroll. Very helpful information. – Rowan McKee Aug 01 '19 at 08:52

NestedScrollView not scrolling when adding TextViews programmatically

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