Tuesday, April 10, 2012

ExpandableListView - hide indicator for groups with no children


In an ExpandableListView , is there a way to hide the group indicator for groups with no children?



Source: Tips4all

2 comments:

  1. The android:groupIndicator property takes a state enabled drawable. That is, you can set different image for different states.

    When the group has no children, the corresponding state is 'state_empty'

    See these reference links:
    http://developer.android.com/reference/android/widget/ExpandableListView.html#attr_android:groupIndicator

    http://developer.android.com/reference/android/R.attr.html#state_empty

    For state_empty, you can set a different image which is not confusing, or, simply use transparent color to display nothing...

    Add this item in your stateful drawable along with others....

    <item android:state_empty="true" android:drawable="@android:color/transparent"/>


    So, your statelist can be like this:

    <selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_empty="true" android:drawable="@android:color/transparent"/>
    <item android:state_expanded="true" android:drawable="@drawable/my_icon_max" />
    <item android:drawable="@drawable/my_icon_min" />
    </selector>


    In case you are using an ExpandableListActivity, you can set the groupindicator in onCreate as follows:

    getExpandableListView().setGroupIndicator(getResources().getDrawable(R.drawable.my_group_statelist));


    I have tested this to be working.

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  2. As mentioned in a different answer, since Android treats an un-expanded list group as empty, the icon is not drawn even if the group has children.

    This link solved the problem for me:
    http://mylifewithandroid.blogspot.com/2011/06/hiding-group-indicator-for-empty-groups.html

    Basically you have to set the default drawable as transparent, move the drawable into your group view as an ImageView and toggle the image in your adapter.

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