Dynamically adding TextView to ScrollView on Android

Question

I try to make a ScrollView to act like a ListView. So every row will be a TextView added dynamically. but the program crashes. I have a ScrollView inside a LinearLayout. What i do wrong? Thanks.

Here is my code

                        scroll = (ScrollView)findViewById(R.id.scrollView1);
                    layout = (LinearLayout) findViewById(R.id.LinearLayout1);
                    layout.setBackgroundColor(Color.TRANSPARENT);
                    TextView[] tx = new TextView[10];
                    for (int i = 0; i < 10; i++) {
                        tx[i] = new TextView(HelloWorldActivity.this);
                        tx[i].setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
                    tx[i].setText("This is the textviewNo" + i);
                    layout.addView(tx[i]);
                    }

                    scroll.addView(layout);

XML:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/RelativeLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_horizontal"
android:orientation="vertical" >

<TextView
    android:id="@+id/timeflag"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="50sp" 
    android:gravity="center"/>



<Button
    android:id="@+id/pause"
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/timeflag"
    android:layout_marginTop="37dp"
    android:text="Start" />


<LinearLayout
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/pause"
    android:orientation="vertical" >

    <ScrollView
        android:id="@+id/scrollView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

    </ScrollView>

</LinearLayout>

</RelativeLayout>

Please add your logcat errors. "the program crashes" is too vague. — Sam
– Sam, Commented Jun 11, 2012 at 17:26

wdziemia · Accepted Answer · 2012-06-11 17:32:14Z

3

A scrollView Can only have one child. If you try to add more than 1 child to the scroll view then it will crash. You should have the LinearLayout inside of the scrollview and then dynamically add textViews to the linear layout.

answered Jun 11, 2012 at 17:32

wdziemia

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1 Comment

Sam Over a year ago

Good eye, but the author is adding a LinearLayout as the ScrollView's child, scroll.addView(layout); In this case the child is also the ScrollView's parent, which is wrong. (What's that song from Deliverance?)

Sam · Accepted Answer · 2012-06-11 17:45:27Z

1

You are trying to add LinearLayout1 as its own child's child (being your own grandfather, is a confusing notion).

Change you XML around like this:

<ScrollView
    android:id="@+id/scrollView1"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/pause"
    >

    <LinearLayout
        android:id="@+id/LinearLayout1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

    </LinearLayout>

</ScrollView>

edited Jun 11, 2012 at 17:45

answered Jun 11, 2012 at 17:34

Sam

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1 Comment

Dheeresh Singh Over a year ago

+1 yes LinearLayout1 is already added in xml and you are again adding it in java (re-parenting it)......

Nino van Hooff · Accepted Answer · 2012-06-11 17:34:37Z

0

You cannot add views to a scrollview. You can only add them to a viewgroup, like linear or relativelayout.

It is not exactly clear what you are trying to achieve, but what is wrong with using a listview for this? You could set a max height on the listview. Or you could try wdziemia's suggestion

answered Jun 11, 2012 at 17:34

Nino van Hooff

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