Calculate the size of a list view or how to tell it to fully expand

Question

I am currently trying to use a ListView inside of a ScrollView. I know from what I\'ve read that this is looked down upon, but I\'m trying to get the ListView to expand com

Answer 1

If you have items with different height you need to use this method:

public void setListViewHeightBasedOnChildren(ListView listView) {

    ListAdapter listAdapter = listView.getAdapter();
    if (listAdapter != null) {

        int numberOfItems = listAdapter.getCount();

        // Get total height of all items.
        int totalItemsHeight = 0;
        for (int itemPos = 0; itemPos < numberOfItems; itemPos++) {
            View item = listAdapter.getView(itemPos, null, listView);
            float px = 300 * (listView.getResources().getDisplayMetrics().density);
            item.measure(
                    View.MeasureSpec.makeMeasureSpec((int)px, View.MeasureSpec.AT_MOST),
                    View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
            int height = item.getMeasuredHeight();
            totalItemsHeight += height;
        }

        // Get total height of all item dividers.
        int totalDividersHeight = listView.getDividerHeight() *
                (numberOfItems - 1);

        // Set list height.
        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalItemsHeight + totalDividersHeight;
        listView.setLayoutParams(params);
        listView.requestLayout();
    }
}

it work just fine with any ListView with any items

Answer 2

If you want a ListView which won't scroll couldn't you just use a LinearLayout?

Answer 3

I ended up overriding onDraw() of the ListView and calculating the average height of the visible rows in the view then estimating the actual height of the list based on how many items are in the adapter. This estimating happens a couple of times until all of the rows are visible.

Answer 4

The correct way to calculate the height is precisely:

int height = 0;
for (int i = 0; i < listView.getChildCount(); i++) {
    height += listView.getChildAt(i).getMeasuredHeight();
    height += listView.getDividerHeight();
}

Answer 5

You should not place your ListView in a ScrollView. The ListView is already scrollable.

The ListView should expand fully by default, if it is the only thing in the layout.

If it is not the only thing in the layout, and you want the ListView to expand to take up all available space, set the layout_weight on the ListView to 1, where all other layout_weight=0.

<LinearLayout android:layout_width="fill_parent" 
             android:layout_height="fill_parent" orientation="vertical">
  <TextView id="@+id/title" 
             android:layout_width="wrap_content" 
            android:layout_height="wrap_content"/>
  <ListView id="@+id/listView" 
            android:layout_width="fill_parent" 
            android:layout_height="0dp" 
            android:layout_weight="1"/>
</LinearLayout>

Edit: The ListView is really designed to be scrollable...the screen layout you have in your screenshot doesn't really seem like the "android way".

However, if your really want to circumvent that, you could try inflating one of the rows, get its minHeight, and multiply that by the number of items in the ListView adapter.

LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.label_value_row, null, false);
int height = adapter.getCount() * view.getMinHeight();

Answer 6

Well, thanks to Rudy, his suggestions was very helpful. Here is how it can be implemented.

1) Create a new class that extends ListView:

package com.example.android.views;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.widget.ListView;

public class ExpandedListView extends ListView {

    private android.view.ViewGroup.LayoutParams params;
    private int old_count = 0;

    public ExpandedListView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (getCount() != old_count) {
            old_count = getCount();
            params = getLayoutParams();
            params.height = getCount() * (old_count > 0 ? getChildAt(0).getHeight() : 0);
            setLayoutParams(params);
        }

        super.onDraw(canvas);
    }

}

2) ... and finally add the new view to your xml layout file:

<com.example.android.views.ExpandedListView
    android:id="@+id/list"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:scrollbars="none"
    android:padding="0px"
    />