Android ignores layout_weight parameter from styles.xml

Question

It looks like android is ignoring layout parameters for ImageButton. When my layout xml defines ImageButtons with the style, layout_weight is considered. However, when I add the button dynamically, the weight is ignored and I have to define LayoutParameters manually.

Styles.xml entry:

<style name="TabbedPanelToolbarControl" parent="android:style/Widget.ImageButton">
    <item name="android:background">@null</item>
    <item name="android:layout_width">wrap_content</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:layout_weight">1.0</item>
    <item name="android:paddingTop">5dp</item>
    <item name="android:paddingBottom">5dp</item>
</style>

Layout xml:

...
<LinearLayout
    android:id="@+id/toolbar"
    android:orientation="vertical" >
    <!-- image buttons go here -->
</LinearLayout>
...

Code:

View view = inflater.inflate(R.layout.test, container, false);
LinearLayout mToolbar = (LinearLayout)view.findViewById(R.id.toolbar);

ImageButton ib = new ImageButton(this.getActivity(), null, R.style.TabbedPanelToolbarControl);

ib.setImageDrawable(icon);
ib.setContentDescription(title);

// ignored layout_weight defined in TabbedPanelToolbarControl style
mToolbar.addView(ib);
// need to re-specify layout
mToolbar.addView(ib, new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 1.0f));

Anyone knows a way to force reading of the layout_weight from styles.xml when adding buttons dynamically?

matiash · Answer 1 · 2014-06-13T23:36:03.883

Reading the layout parameters in the constructor does not work. The reason is quite logical -- when you create the ImageButton

new ImageButton(this.getActivity(), null, R.style.TabbedPanelToolbarControl);

This constructor will read the style attributes. However, since it is not inside a LinearLayout (or any other parent) it has no idea which LayoutParams class it must instantiate. Since the generic ViewGroup.LayoutParams does not have a weight attribute, it will be ignored.

When inflating via LayoutInflater the situation is quite different. The relevant code in the LayoutInflater class is this:

final View view = createViewFromTag(parent, name, attrs);
final ViewGroup viewGroup = (ViewGroup) parent;
final ViewGroup.LayoutParams params = viewGroup.generateLayoutParams(attrs);

Since the viewGroup variable is a fully created LinearLayout, it has an overriden generateLayoutParams() to read both weight and gravity.

score 2 · Accepted Answer · answered Jun 13 '14 at 23:07

2

You can get layout parameters from style and then add ImageButton using these parameters.

    ...
    TypedArray a = obtainStyledAttributes(R.style.TabbedPanelToolbarControl, 
            new int[] {android.R.attr.layout_width,
            android.R.attr.layout_height,
            android.R.attr.layout_weight});


    int width = a.getInt(0, LayoutParams.WRAP_CONTENT);
    int height = a.getInt(1, LayoutParams.WRAP_CONTENT);
    float weight = a.getFloat(2, 1);

    mToolbar.addView(ib, new LayoutParams(width, height, weight));

answered Jun 13 '14 at 23:07

olegr

1,999
18
23

Nice, it worked. Still strange that weight is not considered. It may have something to do with ViewGroup not having weight parameter and only LinearLayout having it. – Vadym Jun 13 '14 at 23:28
@olegr i have similar problem, paddingBottom is not considered in the style. And i am loading the style. do you know why ? – Lena Bru Jun 13 '14 at 23:48
@Ardoramor Try to use `ib.setLayoutParams(new LayoutParams(width, height, weight)); mToolbar.addView(ib);` It has a little bit different implementation. I'm not sure but seems it should work. – olegr Jun 13 '14 at 23:58
@Lena Bru Strange that it is not considered. Should work without additional efforts. Try to ask question with your code examples. – olegr Jun 14 '14 at 00:05
@olegr i did ask the question here is the link http://stackoverflow.com/q/24182411/2136812 – Lena Bru Jun 14 '14 at 00:11

Android ignores layout_weight parameter from styles.xml

2 Answers2