Develop Reference

Android App 50 percent width

I am trying to build a little Android App and I need two LinearLayout side by side. (50/50)
How it looks:
http://i.stack.imgur.com/C9yCF.png
I already try to use: android:layout_width="0dp" android:layout_weight="1" but it didn't work.
This is my XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/part">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="9pt"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:baselineAligned="true"
android:background="#ff7f7f7f"
android:id="#+id/head">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="123456789"
android:id="#+id/textView"
android:paddingStart="3pt"
android:paddingLeft="3pt"
android:textColor="#ffffffff"
android:singleLine="false" />
</LinearLayout>
<LinearLayout
android:id="#+id/left"
android:orientation="vertical"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentBottom="true"
android:layout_below="#+id/head"
android:background="#ffff0100" >
</LinearLayout>
<LinearLayout
android:id="#+id/right"
android:orientation="vertical"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="fill_parent"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_below="#+id/head"
android:background="#fffcff00" />
How it should look:
http://i.stack.imgur.com/tup01.png

Have one more LinearLayout with horizontal orientation below your #+id/head LinearLayout.
Set its width to match_parent. Keep the last two LinearLayouts inside the new LinearLayout and have android:layout_weight=0.5 for both. Something like:
<RelativeLayout>
<LinearLayout> </LinearLayout>
<LinearLayout
...
android:orientation:"horizontal"/>
<LinearLayout
android:weight="0.5"
android:width="0dp"
... />
</LinearLayout>
<LinearLayout
android:weight="0.5"
android:width="0dp"
... />
</LinearLayout>
</LinearLayout>
</RelativeLayout>

You can't use layout_weight with RelativeLayouts children. Put/Wrap both LinearLayouts in another LinearLayout.

Hey try this code...
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/part"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="#+id/head"
android:layout_width="fill_parent"
android:layout_height="9pt"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:background="#ff7f7f7f"
android:baselineAligned="true"
android:orientation="vertical" >
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="3pt"
android:paddingStart="3pt"
android:singleLine="false"
android:text="123456789"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textColor="#ffffffff" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/head"
android:orientation="horizontal" >
<LinearLayout
android:id="#+id/left"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#ffff0100"
android:orientation="vertical" >
</LinearLayout>
<LinearLayout
android:id="#+id/right"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#fffcff00"
android:orientation="vertical" />
</LinearLayout>

How to merge Linear Layout and Table Layout at android?

I'm new android. I have a little bit stack in designing layout for Android. In my scenario, I have two button with Linear Layout. Here my xml.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal"
android:background="#color/isp_home_color"
>
<Button
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_weight="1"
android:text="#string/sync_text"
android:background="#color/sync_text_color"
android:id="#+id/btn_syncpin"
android:layout_gravity="left"
android:textStyle="bold"
/>
<Button
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="70dp"
android:text="#string/topup_text"
android:background="#color/topup_text_color"
android:id="#+id/btn_topup"
android:layout_gravity="right"
android:textStyle="bold"/>
<!--Table Layout will come here -->
</LinearLayout>
Here image for this.
When I add new TableLayout inside Linear Layout. I got this.
Here my xml for Table Layout.
<TableLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</TableLayout>
Actually, I don't want like this. I want two button as shown in first image. Then, next table layout will occur under this two button. Please help me how can I do this layout. Please pointing to me how to make this. Thanks with advanced.

Give orientation as vertical to the LinearLayout not the TableLayout.Put Two buttons in a LinearLayout with orizontal orientation and give orientation "vertical" for the parent LinearLayout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#456789"
android:orientation="vertical" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF"
android:orientation="horizontal">
<Button
android:id="#+id/btn_syncpin"
android:layout_width="wrap_content"
android:layout_height="70dp"
android:layout_gravity="left"
android:layout_weight="1"
android:background="#123456"
android:text="tring/"
android:textStyle="bold" />
<Button
android:id="#+id/btn_topup"
android:layout_width="wrap_content"
android:layout_height="70dp"
android:layout_gravity="right"
android:layout_weight="1"
android:background="#978969"
android:text="topup_text"
android:textStyle="bold" />
</LinearLayout>
<TableLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF" >
</TableLayout>
</LinearLayout>

Check this out, I just checked it on my Machine and it works as desired, although the background preference and the display strings have been removed.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Button
android:id="#+id/btn_syncpin"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_gravity="left"
android:layout_weight="1"
android:textStyle="bold" />
<Button
android:id="#+id/btn_topup"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_gravity="right"
android:layout_weight="1"
android:textStyle="bold" />
</LinearLayout>
<TableLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_below="#+id/linearLayout2">
</TableLayout>
</RelativeLayout>

take Relative Layout as a parent layout.
Following is an example. it will display your buttons and table layout too
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#color/isp_home_color"
android:orientation="horizontal" >
<Button
android:id="#+id/btn_syncpin"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_gravity="left"
android:layout_weight="1"
android:background="#color/sync_text_color"
android:text="#string/sync_text"
android:textStyle="bold" />
<Button
android:id="#+id/btn_topup"
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_gravity="right"
android:layout_weight="1"
android:background="#color/topup_text_color"
android:text="#string/topup_text"
android:textStyle="bold" />
</LinearLayout>
<TableLayout
android:id="#+id/table"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/linearLayout2" >
</TableLayout>
</RelativeLayout>
thanks

This answer tells only implementation of button_bar_layout for all android versions with buttons at the bottom/top of an activity which look like AlertDialog with OK/Cancel buttons.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="?android:attr/listDivider"
android:orientation="vertical"
android:showDividers="middle" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#null"
android:divider="?android:attr/listDivider"
android:dividerPadding="12dp"
android:orientation="horizontal"
android:showDividers="middle" >
<Button
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#android:drawable/list_selector_background"
android:paddingLeft="4dp"
android:paddingRight="4dp"
android:text="One" />
<Button
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:background="#android:drawable/list_selector_background"
android:paddingLeft="4dp"
android:paddingRight="4dp"
android:text="Two" />
</LinearLayout>
<TableLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF" >
</TableLayout>
</LinearLayout>
Credits: Who else ? Johnkil

// try this way here i gave you alternative to achieve your requirement from give all of above
1. header.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:background="#color/isp_home_color">
<Button
android:layout_width="0dp"
android:layout_height="70dp"
android:layout_weight="1"
android:text="#string/sync_text"
android:background="#color/sync_text_color"
android:id="#+id/btn_syncpin"
android:textStyle="bold"/>
<Button
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="70dp"
android:text="#string/topup_text"
android:background="#color/topup_text_color"
android:id="#+id/btn_topup"
android:textStyle="bold"/>
</LinearLayout>
2.main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp"
android:orientation="vertical">
<include
layout="#layout/header"/>
<TableLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginTop="10dp"
android:layout_weight="1">
</TableLayout>
</LinearLayout>

3 layouts - middle is flexible

I need the following thing:
3 layouts:
Header
Content
Footer
Header must be on the top footer must be sticked to the bottom (android:layout_alignParentBottom="true").
But how to make middle to occupy the whole other screen? Thanks.

Here is my solution (with android:layout_weight and ScrollView):
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#DDDDDD"
android:gravity="center"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Header"
tools:ignore="HardcodedText" />
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="3" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Content"
tools:ignore="HardcodedText" />
</ScrollView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="#DDDDDD"
android:gravity="center"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Footer"
tools:ignore="HardcodedText" />
</LinearLayout></LinearLayout>
And the result picture :

Hi Use the following lines
<?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" >
<LinearLayout
android:id="#+id/button1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="Button" >
<Button
android:id="#+id/button2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Header" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_above="#+id/linearfooter"
android:layout_below="#+id/button1"
android:background="#android:color/darker_gray"
>
</LinearLayout>
<LinearLayout
android:id="#+id/linearfooter"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="Button" >
<Button
android:id="#+id/button2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="footer" />
</LinearLayout>
</RelativeLayout>
hope this helps you.

Use a height of 0dp and
android:layout_weight
set to 1

Finally I've got the next solution:
To the middle layout I added:
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#id/footer"
android:layout_below="#id/header"
android:layout_weight="1">
And it works!

Align a layout to the top of another layout in order to make a status bar

I have a layout like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/parent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#e4e8ed"
android:gravity="top" >
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/app"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="0px"
android:orientation="vertical"
android:padding="0px" >
<include
android:id="#+id/tabBar"
layout="#layout/tab" />
<Button
android:id="#+id/nist"
android:layout_width="match_parent"
android:layout_height="67dp"
android:layout_gravity="center_horizontal"
android:layout_marginBottom="3dp"
android:layout_marginLeft="3dp"
android:layout_marginRight="3dp"
android:layout_marginTop="3dp"
android:background="#drawable/ready"
android:textColor="#FFFFFF" />
<ListView
android:id="#+id/lastCases"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="2.08"
android:longClickable="true" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="7dp"
android:layout_below="#id/app"
android:background="#drawable/dropshadow_custom" >
<TextView
android:id="#+id/error"
style="#style/AudioFileInfoOverlayText"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="120dp"
android:gravity="center"
android:text="No Cases"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#D6D8D9"
android:textSize="40dp" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/app"
android:background="#000000"
android:gravity="bottom"
android:orientation="vertical" >
</LinearLayout>
</RelativeLayout>
I try to align the last LinearLayout on top of the layout which holds the ListView by using this tag: android:layout_alignTop="#+id/app" But it doesn't seem to work. How can accomplish this?
Many Thanks!

Without any content a Layout with layout_width="wrap_content" and layout_height="wrap_content" is not shown as its width and height have a value of 0! Even if you have set some background color nothing will appear! You either have to add some content to the layout or you have to define another layout dimension. The position of your layout with android:layout_alignTop="#+id/app" should be correct. Hope that helps.

You can set "layout_below" on the first layout targeting to the last layout.
The code is that, I put a button inside the top layout as an exemple (Obs: In your listview you should use 0dp in layout_weight cause you already use layout_weight ^^) :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/parent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#e4e8ed"
android:gravity="top" >
<LinearLayout
android:id="#+id/app"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="0px"
android:orientation="vertical"
android:layout_below="#+id/top"
android:padding="0px" >
<Button
android:id="#+id/nist"
android:layout_width="match_parent"
android:layout_height="67dp"
android:layout_gravity="center_horizontal"
android:layout_marginBottom="3dp"
android:layout_marginLeft="3dp"
android:layout_marginRight="3dp"
android:layout_marginTop="3dp"
android:textColor="#FFFFFF" />
<ListView
android:id="#+id/lastCases"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2.08"
android:longClickable="true" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="7dp"
android:layout_below="#+id/app" >
<TextView
android:id="#+id/error"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginTop="120dp"
android:gravity="center"
android:text="No Cases"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#D6D8D9"
android:textSize="40dp" />
</LinearLayout>
<LinearLayout
android:id="#+id/top"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:background="#000000"
android:gravity="bottom"
android:orientation="vertical" >
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Top"
/>

How to make a linearlayout filling remaining space in a relativelayout?

I've got a relativelayout with three linearlayouts as children. The last one has a fixed height and has android:layout_alignParentBottom set to "true". While the middle one is properly positioned below the first one, it goes as far as the bottom of the screen, so that its lower part is overlapped by the third one.
What's wrong?
Thanks
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="#+id/category"
android:layout_width="fill_parent"
android:layout_height="50dp"
android:layout_alignParentTop="true"
android:orientation="horizontal" >
<ImageView
android:id="#+id/back_btn"
android:layout_width="29dp"
android:layout_height="34dp"
android:layout_gravity="center_vertical"
android:src="#drawable/red_arrow_left" />
<TextView
android:id="#+id/cat_name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:gravity="center"
android:textSize="20sp" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/category"
android:layout_marginTop="10dp"
android:orientation="horizontal" >
<ListView
android:id="#+id/android:list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/white"
android:cacheColorHint="#android:color/white" />
<TextView
android:id="#+id/android:empty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/white"
android:cacheColorHint="#android:color/white"
android:padding="10dp"
android:text="#string/no_item" />
</LinearLayout>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/nav_bar"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:layout_alignParentBottom="true"
android:orientation="horizontal" >
//stuff
</LinearLayout>
</RelativeLayout>

You could try using layout weights to control the relative sizes of the child layouts. There is an article on my blog which gives some information on the use of layout weights.
As an example, try this:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/category"
android:layout_width="fill_parent"
android:layout_height="50dp"
android:orientation="horizontal" >
<ImageView
android:id="#+id/back_btn"
android:layout_width="29dp"
android:layout_height="34dp"
android:layout_gravity="center_vertical" />
<TextView
android:id="#+id/cat_name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:gravity="center"
android:textSize="20sp" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/category"
android:layout_marginTop="10dp"
android:layout_weight="1"
android:orientation="horizontal" >
<ListView
android:id="#+id/android:list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/white"
android:cacheColorHint="#android:color/white" />
<TextView
android:id="#+id/android:empty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/white"
android:cacheColorHint="#android:color/white"
android:padding="10dp"
android:text="no_item" />
</LinearLayout>
<LinearLayout
android:id="#+id/nav_bar"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:orientation="horizontal" >
//stuff
</LinearLayout>
</LinearLayout>
The RelativeLayout has been replaced by a LinearLayout, all of the relative positioning tags have been removed, and a layout_weight attribute has been added to the centre LinearLayout which will cause it to stretch to fill the available space.

Nooo... the solution is much simpler! You forgot to say that you wanted the second linear layout to be above the third one :) Yes, the second linear layout must have BOTH android:layout_below="#+id/category" and android:layout_above="#+id/nav_bar". I tested it and it works.
But of course, you can use weights to achieve the same results, it is just going to be harder...
Here is your XML with the change I mentioned (tested it in eclipse):
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="#+id/category"
android:layout_width="fill_parent"
android:layout_height="50dp"
android:layout_alignParentTop="true"
android:orientation="horizontal" >
<ImageView
android:id="#+id/back_btn"
android:layout_width="29dp"
android:layout_height="34dp"
android:layout_gravity="center_vertical"
android:src="#drawable/red_arrow_left" />
<TextView
android:id="#+id/cat_name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:gravity="center"
android:textSize="20sp" />
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_above="#+id/nav_bar"
android:layout_below="#+id/category"
android:layout_marginTop="10dp"
android:orientation="horizontal" >
<ListView
android:id="#+id/android:list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/white"
android:cacheColorHint="#android:color/white" />
<TextView
android:id="#+id/android:empty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/white"
android:cacheColorHint="#android:color/white"
android:padding="10dp"
android:text="#string/no_item" />
</LinearLayout>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/nav_bar"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:layout_alignParentBottom="true"
android:orientation="horizontal" >
//stuff
</LinearLayout>
</RelativeLayout>

You should add an id to your second LinearLayout
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/category"
android:layout_marginTop="10dp"
android:id="#+id/YOUR_ID">
and in the third layout add android:layout_below="#id/YOUR_ID"
<LinearLayout
android:id="#+id/nav_bar"
android:layout_below="#id/YOUR_ID"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="40dp"
android:layout_alignParentBottom="true">