Use a transparent button in TableView cells on Android

Question

Please take a look at the following layout. This layout is used in a TableView and is applied in each row. The question is why the button in each tablerow is only clickable in the upper half of the tableviewcell when transparency is applied. Without transparency the button fills up the correct amount of space.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="10dp"
    android:paddingTop="10dp" >

    <ImageButton
        android:id="@+id/btnSelect"
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:background="@color/white"
        android:contentDescription="Geselecteerde rekening"
        android:src="@drawable/checkbox_akkoord_uit" />

    <ImageView
        android:id="@+id/imgPhoto"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_alignBottom="@+id/btnSelect"
        android:layout_marginLeft="4dp"
        android:layout_centerVertical="true"
        android:layout_toRightOf="@+id/btnSelect"
        android:scaleType="fitCenter"
        android:src="@drawable/icon_foto" />

    <ImageView
        android:id="@+id/imgPencil"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_alignBottom="@+id/btnSelect"
        android:layout_marginLeft="4dp"
        android:layout_centerVertical="true"
        android:layout_toRightOf="@+id/btnSelect"
        android:src="@drawable/potlood" />

    <ImageView
        android:id="@+id/ivDrag"
        android:layout_width="20dp"
        android:layout_height="20dp"
        android:layout_alignParentRight="true"
        android:layout_marginRight="@dimen/activity_horizontal_margin"
        android:layout_centerVertical="true"
        android:src="@drawable/settings" />

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="8dip"
        android:layout_toLeftOf="@+id/ivDrag"
        android:layout_toRightOf="@+id/imgPhoto"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/txtDescription"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:maxLines="1"
            android:text="Medium Text Medium Text"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:textColor="@color/green"
            android:textSize="@dimen/text_size_1" />

        <TextView
            android:id="@+id/txtProductname"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:maxLines="1"
            android:text="Small Text"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:textColor="@color/green"
            android:textSize="@dimen/text_size_2" />

        <TextView
            android:id="@+id/txtAccountnumber"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:maxLines="1"
            android:text="Medium Text"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:textColor="@color/green"
            android:textSize="@dimen/text_size_3" />
    </LinearLayout>

<Button
    android:id="@+id/btnModify"
    android:background="@android:color/transparent"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:layout_toRightOf="@+id/btnSelect"
    android:layout_toLeftOf="@+id/ivDrag" />

Any help is greatly appreciated! Regards, Raoul

Answer 1

Turns out that the Button needs a minimum height. So the altered XML definition could be:

<Button
    android:id="@+id/btnModify"
    android:background="@android:color/transparent"
    android:minHeight="40dp"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@+id/btnSelect"
    android:layout_toLeftOf="@+id/ivDrag" />

This worked for me!

Regards, Raoul.