ListView Item is not clickable in Android

In this ListView is not clickable, I want to perform an action on item click but I do not know why this is not clickable, I have also checked in debugging the controller is not gone in itemclicklistener.

Design file :

  <?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:orientation="vertical" >

<CheckBox
    android:id="@+id/cbSolved"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="15dp"
    android:layout_marginTop="20dp"
    android:text="Show Solved" />

 <CheckBox
    android:id="@+id/cbMyCases"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBaseline="@+id/cbSolved"
    android:layout_alignBottom="@+id/cbSolved"
    android:layout_alignParentRight="true"
    android:layout_marginRight="46dp"
    android:text="My Cases" />

<EditText
    android:id="@+id/etCaseSeacrh"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/cbSolved"
    android:layout_marginLeft="28dp"
    android:ems="10"
    android:hint="Search" >
</EditText>

<ListView
    android:id="@+id/liCases"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_above="@+id/btnNewCase"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/etCaseSeacrh"
    android:layout_marginTop="23dp"
    android:clickable="true" >
</ListView>

<Button
    android:id="@+id/btnNewCase"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParen