Develop Reference

Android Grey Out LinearLayout

I have a linear layout which contains a set of child views (mixture of text, images and other layouts).
I want to grey out the linear layout and all the child views so they look disabled (similar to how a button works).
Is this possible to achieve? I know i can set a colour filter when painting on the canvas, is there something similar for layouts?

Another way is to call setEnabled() on each child (for example if you want to do some extra check on child before disabling), check out this answer:
https://stackoverflow.com/a/7069377/4840812

You can use Frame-layout
Using TEST ONE you can achieve above text view like disabled. You can set root layout clickable false for actually disable views inside layout.
TEST TWO is for understanding purpose. Like you need to manage order of view to show effect.
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!--THIS IS TEST ONE-->
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_marginTop="150dp"
android:background="#000000"
android:gravity="center"
android:text="TEST DATA"
android:textColor="#android:color/white"
android:textSize="30sp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="200dp"
android:background="#DAD6D6D6"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Data"
android:textColor="#color/colorAccent"
android:textSize="30sp" />
</LinearLayout>
<!--THIS IS TEST TWO-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_marginTop="300dp"
android:background="#DAD6D6D6"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Data"
android:textColor="#color/colorAccent"
android:textSize="30sp" />
</LinearLayout>
<TextView
android:layout_width="match_parent"
android:layout_height="100dp"
android:layout_marginTop="400dp"
android:background="#000000"
android:gravity="center"
android:text="TEST DATA"
android:textColor="#android:color/white"
android:textSize="30dp" />
</FrameLayout>

To achieve your layout you can use the RelativeLayout. In RelativeLayout you can use the 2 different views or LinearLayout. In first layout you can add views according to your need, and In second layout you can set the alpha colorcode for disable the layout.
Please try below code:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerInParent="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/demo_img_1" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/demo_img_1"
android:layout_marginLeft="20dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/trans"/>
</RelativeLayout>
Here is output for code:

Linear Layout inside Frame Layout stops working

My Layout is working fine, It has a parent Linear Layout and multiple Linear Layouts inside it.
Now i need to add a background image,So that i need to add a frame layout here.
When i change parent Linear Layout to Frame Layout, it disappears all the items in the linear layout.
If i add Frame Layout,inside Linear Layout it disappears all the items in the Linear layout.
I am unable to understand how to put a frame layout without removing Linear Layout items.
The Layout code is quite long.
I am putting above part of it.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="6"
android:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal"
android:layout_marginTop="20dp"
android:layout_marginLeft="30dp"
android:layout_marginRight="30dp"
>
<ImageView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.8"
android:src="#drawable/image11"
/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical"
android:paddingTop="10dp"
>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="7:00 PM CST"
android:layout_gravity="center"
android:gravity="center"
android:textColor="#color/white"
android:fontFamily="sans-serif-medium"
android:textSize="12sp"
/>
</LinearLayout>
<ImageView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.8"
android:src="#drawable/icon2"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="40dp"
android:orientation="horizontal"
android:paddingLeft="20dp"
android:paddingRight="20dp"
>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="4"
android:orientation="vertical"
android:background="#drawable/cart_custom_background"
android:paddingBottom="2dp"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="4"
android:orientation="horizontal"
android:layout_marginRight="1dp"
android:layout_marginLeft="1dp"
>

Now i need to add a background image,So that i need to add a frame
layout here.
You don't need to add another layout to give background. Your root (or even any other)<LinearLayout> should be enough. You can set the background using:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/my_drawable" > // Can also give color here
When i change parent Linear Layout to Frame Layout, it disappears all
the items in the linear layout.
Thats primarily because the <FrameLayout> unlike <LinearLayout> kept adding all the children on top of each other.

Show 3 scrollable ListViews of equal height in Android Layout

I am trying to show three different vertical sections in my Android layout on one screen, each taking up one third of the screen, one on the top, one in the middle, and one on the bottom. Each section has a TextView and a ListView, and the ListViews can scroll so that you can see all items, but the overall page does not move. I have tried putting each TextView and ListView in a LinearLayout and setting the height of each LinearLayout to one third the total height of the screen, but the first ListView just shows all the items in it, taking up most of the screen, and the other sections are pushed down. I also tried using layout_weights, but for some reason it did not work. (EDIT: Setting layout_weight="1" ended up working, I'm not sure what I did wrong the first time) How can I make this work, or is there a better way to go about this?

<LinearLayout
android:layout_width="match_parent" android:layout_height="match_parent"
android:orientation="horizontal" >
<ListView android:layout_width="0dp" android:layout_weight="1"
android:layout_height="match_parent" android:background="#FF0000"/>
<ListView android:layout_width="0dp" android:layout_weight="1"
android:layout_height="match_parent" android:background="#00FF00">
<ListView android:layout_width="0dp" android:layout_weight="1"
android:layout_height="match_parent" android:background="#0000FF">
</LinearLayout>
This will give you three equally wide columns: to make it rows, change the orientation to vertical and swap the values of layout_height and layout_width for each listview. If you need to add the TextViews, you'll have to make each listview in this code either a RelativeLayout LinearLayout or FrameLayout, using same width/height/weight and arranging the ListView and TextView inside to taste. To do this most efficiently, use a Framelayout and use a margin on the listview to offset it from the TextView. You can place the TextView relative to the ListView inside the FrameLayout by using the layout_gravity in the TextView.
Ie (swapping the first "column"):
<FrameLayout android:orientation="vertical" android:layout_width="0dp"
android:layout_weight="1" android:layout_height="match_parent"
android:background="#FF0000">
<TextView android:text="Column!" android:background="#3Eff0000"
android:layout_height="40dp" android:layout_width="match_parent">
<ListView android:layout_marginTop="48dp" android:layout_height="match_parent"
android:layout_width="match_parent" android:background="#8Aff0000"/>
</FrameLayout>

Use this:
<?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:orientation="horizontal"
android:weightSum="3">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#ff89ff91">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="#1"
android:id="#+id/textView"
android:padding="5dp"
android:gravity="center" />
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/listView"
android:layout_below="#+id/textView" />
</RelativeLayout>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#ffff8177">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="#2"
android:id="#+id/textView2"
android:padding="5dp"
android:gravity="center" />
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/listView2"
android:layout_below="#+id/textView2" />
</RelativeLayout>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:background="#ffffe85d">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="#3"
android:id="#+id/textView3"
android:padding="5dp"
android:gravity="center" />
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/listView3"
android:layout_below="#+id/textView3" />
</RelativeLayout>
</LinearLayout>

vertical layout little issue

I have a LinearLayout (vertical) and it should contain 3 elements in the following order: textview, listview and button. The listview could be really high so in order to keep all the 3 elements visible I put the 3 elements each one inside another layout. So my structure is like:
linear layout (vertical)
linear layout (horizontal)
textview
linear layout (vertial) *
listview
relative layout
button
In order to get it working I set a fixed height to the vertical linearlayout which only contains the listview (*) but I know it is a bad choice because on bigger devices there will be a lot of empty space. How can I fix it?
thanks

User percentage values for the LinearLayout(*), so they take up a percentage of the parent's height,
and for the rest, if you want them to take up remaining space, add attribute: android:layout_weight:1;

Implement your layout this way :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/mTextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:gravity="center"
android:padding="10dp"
android:text="Header Text" />
<ListView
android:id="#+id/mListView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_above="#+id/mButton"
android:layout_below="#+id/mTextView" >
</ListView>
<Button
android:id="#+id/mButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="Button1" />
</RelativeLayout>

// try this
<?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">
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="match_parent">
<TextView
android:id="#+id/textview"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="textview"/>
</LinearLayout>
<LinearLayout
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_marginTop="5dp"
android:layout_weight="1">
<ListView
android:layout_height="match_parent"
android:layout_width="match_parent"
android:cacheColorHint="#00000000"
android:divider="#null"
android:dividerHeight="0dp"
android:smoothScrollbar="true"
android:id="#+id/listview"/>
</LinearLayout>
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:layout_marginTop="5dp"
android:gravity="center">
<Button
android:id="#+id/button"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="button"/>
</LinearLayout>
</LinearLayout>

How do I align views at the bottom of the screen?

Here's my layout code;
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:text="#string/welcome"
android:id="#+id/TextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</TextView>
<LinearLayout android:id="#+id/LinearLayout"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="bottom">
<EditText android:id="#+id/EditText"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</EditText>
<Button android:text="#string/label_submit_button"
android:id="#+id/Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
</LinearLayout>
</LinearLayout>
What this looks like is on the left and what I want it to look like is on the right.
The obvious answer is to set the TextView to fill_parent on height, but this causes no room to be left for the button or entry field.
Essentially the issue is that I want the submit button and the text entry to be a fixed height at the bottom and the text view to fill the rest of the space. Similarly, in the horizontal linear layout I want the submit button to wrap its content and for the text entry to fill the rest of the space.
If the first item in a linear layout is told to fill_parent it does exactly that, leaving no room for other items. How do I get an item which is first in a linear layout to fill all space apart from the minimum required by the rest of the items in the layout?
Relative layouts were indeed the answer:
<?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">
<TextView
android:text="#string/welcome"
android:id="#+id/TextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true">
</TextView>
<RelativeLayout
android:id="#+id/InnerRelativeLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" >
<Button
android:text="#string/label_submit_button"
android:id="#+id/Button"
android:layout_alignParentRight="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
<EditText
android:id="#+id/EditText"
android:layout_width="fill_parent"
android:layout_toLeftOf="#id/Button"
android:layout_height="wrap_content">
</EditText>
</RelativeLayout>
</RelativeLayout>

The modern way to do this is to have a ConstraintLayout and constrain the bottom of the view to the bottom of the ConstraintLayout with app:layout_constraintBottom_toBottomOf="parent"
The example below creates a FloatingActionButton that will be aligned to the end and the bottom of the screen.
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_height="match_parent"
android:layout_width="match_parent">
<android.support.design.widget.FloatingActionButton
android:layout_height="wrap_content"
android:layout_width="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
</android.support.constraint.ConstraintLayout>
For reference, I will keep my old answer.
Before the introduction of ConstraintLayout the answer was a relative layout.
If you have a relative layout that fills the whole screen you should be able to use android:layout_alignParentBottom to move the button to the bottom of the screen.
If your views at the bottom are not shown in a relative layout then maybe the layout above it takes all the space. In this case you can put the view, that should be at the bottom, first in your layout file and position the rest of the layout above the views with android:layout_above. This enables the bottom view to take as much space as it needs, and the rest of the layout can fill all the rest of the screen.

In a ScrollView this doesn't work, as the RelativeLayout would then overlap whatever is in the ScrollView at the bottom of the page.
I fixed it using a dynamically stretching FrameLayout :
<ScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:fillViewport="true">
<LinearLayout
android:id="#+id/LinearLayout01"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical">
<!-- content goes here -->
<!-- stretching frame layout, using layout_weight -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
</FrameLayout>
<!-- content fixated to the bottom of the screen -->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<!-- your bottom content -->
</LinearLayout>
</LinearLayout>
</ScrollView>

You can keep your initial linear layout by nesting the relative layout within the linear layout:
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:text="welcome"
android:id="#+id/TextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</TextView>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button android:text="submit"
android:id="#+id/Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true">
</Button>
<EditText android:id="#+id/EditText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toLeftOf="#id/Button"
android:layout_alignParentBottom="true">
</EditText>
</RelativeLayout>
</LinearLayout>

The answer above (by Janusz) is quite correct, but I personnally don't feel 100% confortable with RelativeLayouts, so I prefer to introduce a 'filler', empty TextView, like this:
<!-- filler -->
<TextView android:layout_height="0dip"
android:layout_width="fill_parent"
android:layout_weight="1" />
before the element that should be at the bottom of the screen.

You can do this with a LinearLayout or a ScrollView, too. Sometimes it is easier to implement than a RelativeLayout. The only thing you need to do is to add the following view before the Views you want to align to the bottom of the screen:
<View
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_weight="1" />
This creates an empty view, filling the empty space and pushing the next views to the bottom of the screen.

1. Use ConstraintLayout in your root Layout
And set app:layout_constraintBottom_toBottomOf="parent" to let the Layout on the bottom of the screen:
<LinearLayout
android:id="#+id/LinearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent">
</LinearLayout>
2. Use FrameLayout in your root Layout
Just set android:layout_gravity="bottom" in your layout
<LinearLayout
android:id="#+id/LinearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:orientation="horizontal">
</LinearLayout>
3. Use LinearLayout in your root Layout (android:orientation="vertical")
(1) Set a layout android:layout_weight="1" on the top of the your Layout
<TextView
android:id="#+id/TextView"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:text="welcome" />
(2) Set the child LinearLayout for android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="bottom"
The main attribute is ndroid:gravity="bottom", let the child View on the bottom of Layout.
<LinearLayout
android:id="#+id/LinearLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="bottom"
android:orientation="horizontal">
</LinearLayout>
4. Use RelativeLayout in the root Layout
And set android:layout_alignParentBottom="true" to let the Layout on the bottom of the screen
<LinearLayout
android:id="#+id/LinearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:orientation="horizontal">
</LinearLayout>
Output

This also works.
<LinearLayout
android:id="#+id/linearLayout4"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_below="#+id/linearLayout3"
android:layout_centerHorizontal="true"
android:orientation="horizontal"
android:gravity="bottom"
android:layout_alignParentBottom="true"
android:layout_marginTop="20dp"
>
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
/>
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
/>
</LinearLayout>

Following up on Timores's elegant solution, I have found that the following creates a vertical fill in a vertical LinearLayout and a horizontal fill in a horizontal LinearLayout:
<Space
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1" />

You don't even need to nest the second relative layout inside the first one. Simply use the android:layout_alignParentBottom="true" in the Button and EditText.

If you don't wish to make many changes, then you could just put:
android:layout_weight="1"
for the TextView having ID as #+id/TextView i.e
<TextView android:text="#string/welcome"
android:id="#+id/TextView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1">
</TextView>

Creating both header and footer, here is an example:
Layout XML
<RelativeLayout
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:background="#color/backgroundcolor"
tools:context=".MainActivity">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="40dp"
android:background="#FF0000">
</RelativeLayout>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="40dp"
android:layout_alignParentBottom="true"
android:background="#FFFF00">
</RelativeLayout>
</RelativeLayout>
Screenshot

For a case like this, always use RelativeLayouts. A LinearLayout is not intended for such a usage.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/db1_root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- Place your layout here -->
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_gravity="bottom"
android:orientation="horizontal"
android:paddingLeft="20dp"
android:paddingRight="20dp" >
<Button
android:id="#+id/setup_macroSavebtn"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Save" />
<Button
android:id="#+id/setup_macroCancelbtn"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Cancel" />
</LinearLayout>
</RelativeLayout>

Use the below code. Align the button to buttom. It's working.
<?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:orientation="vertical" >
<Button
android:id="#+id/btn_back"
android:layout_width="100dp"
android:layout_height="80dp"
android:text="Back" />
<TextView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.97"
android:gravity="center"
android:text="Payment Page" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Submit"/>
</LinearLayout>
</LinearLayout>

Use android:layout_alignParentBottom="true" in your <RelativeLayout>.
This will definitely help.

In case you have a hierarchy like this:
<ScrollView>
|-- <RelativeLayout>
|-- <LinearLayout>
First, apply android:fillViewport="true" to the ScrollView and then apply android:layout_alignParentBottom="true" to the LinearLayout.
This worked for me perfectly.
<ScrollView
android:layout_height="match_parent"
android:layout_width="match_parent"
android:scrollbars="none"
android:fillViewport="true">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="#+id/linearLayoutHorizontal"
android:layout_alignParentBottom="true">
</LinearLayout>
</RelativeLayout>
</ScrollView>

You can just give your top child view (the TextView #+id/TextView) an attribute:
android:layout_weight="1".
This will force all other elements below it to the bottom.

This can be done with a linear layout too.
Just provide Height = 0dp and weight = 1 to the layout above and the one you want in the bottom. Just write height = wrap content and no weight.
It provides wrap content for the layout (the one that contains your edit text and button) and then the one that has weight occupies the rest of the layout.
I discovered this by accident.

I used the solution Janusz posted, but I added padding to the last View since the top part of my layout was a ScrollView.
The ScrollView will be partly hidden as it grows with content. Using android:paddingBottom on the last View helps show all the content in the ScrollView.