Develop Reference

Android - nested layouts

I have built the following XML layout:
<?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:background="#color/white"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/ll1"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="0.2"
android:orientation="horizontal" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="0.3"
android:gravity="center"
android:src="#drawable/logo" />
<TextView
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="0.7"
android:gravity="center"
android:text="#string/my_profile"
android:textColor="#A669DA"
android:textSize="20sp" />
</LinearLayout>
<LinearLayout
android:id="#+id/ll2"
android:background="#A669DA"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="0.15"
android:orientation="horizontal" >
<TextView
android:id="#+id/TextView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginLeft="10dp"
android:layout_marginTop="20dp"
android:text="#string/payroll_header"
android:textColor="#FFFFFF"
android:textSize="20sp" />
</LinearLayout>
<ScrollView
android:id="#+id/scrollView1"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:layout_weight="0.65" >
<LinearLayout
android:id="#+id/ll3"
android:layout_width="fill_parent"
android:layout_height="0dp"
android:orientation="vertical"
android:weightSum="2" >
<ExpandableListView
android:id="#+id/expandableListView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fadeScrollbars="true" >
</ExpandableListView>
<HorizontalScrollView
android:id="#+id/horizontalScrollView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<ExpandableListView
android:id="#+id/expandableListView2"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ExpandableListView>
</HorizontalScrollView>
<ListView
android:id="#+id/listView1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</ListView>
</LinearLayout>
</ScrollView>
</LinearLayout>
The root element of this XML layout is a linear layout. It contains 2 linear layouts and one scroll. Since scroll view can only have one child, it contains a linear layout which in turn contains an expandable listView, horizontal scrollview (which contains an expandable listview) and a listview. As you can see, this is a very complicated layout, and I think it should be possible to simplify. Basically, I want the top 2 linear layouts to always take 35% of the screen, and the scrollview to take the rest. That's why I gave a weight of 0.2 to the first linear layout, 0.15 to the second linear layout, and 0.65 to scrollView.
Within the scrollView, I would like each of the 3 elements to take as much space as they would need, so that user scrolls down if he/she doesn't see everything. I know that expandableListView and ListView are already scrollable, so I will disable scrolling in them, so that parent's scroll bar is used.
However, I am facing several problems with this design:
1) In the first screenshot, you can see an expandableListView, horizontalScrollBar (with an expandableListView), and a listView.
Each of them has height set to "wrap content", so I would expect each of them to take as much space as they need. However, you can see in the second screenshot that when I open the second expandable listView (the one within a horizontal scrollBar), listview doesn't move down to make space for the expanded list view. How can I achieve it, so that each of them moves down when the expandable list above expands? Is the only way to do it is to combine them all in one expandableListView?
2) My second expandableListView is in the horizontalScrollBar, however, I can't scroll it horizontally. Can I even put horizontal scrollBar inside a vertical scrollBar?

First off, a little simplification: Your second LinearLayout (the 0.15 one) can be left out since it only has a single child. Just be sure to adjust the layout parameters of that single child (the TextView).
For your problem #1, try calling invalidate() or requestLayout() on your root view.
Problem #2 is actually solved: Link
My general impression is that this nesting of ScrollViews and ListViews is pretty complex. Have you considered alternatives such as TabLayout or DrawerLayout?
Cheers

Invisible components still take up space

So, I have this one activity that looks like this:
http://i.imgur.com/UzexgEA.jpg
As you can see, it has a button, a list and a button.
If certain conditions are met, I want to hide both buttons just show the list, but as you can see in the next image, the buttons are still taking up space:
http://i.imgur.com/OyLIfSk.jpg
So my question, what can I do to enlarge the list to take that space out?
Here is my layout for the buttons and the list:
<?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" >
<Button
android:id="#+id/findSelected"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="registrarAsistencia"
android:text="Registrar Asistencia" />
<ListView
android:id="#+id/listaAlumnos"
android:layout_width="fill_parent"
android:layout_height="376dp"
android:layout_weight="2.29" />
<Button
android:id="#+id/btnChecarBoxes"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="seleccionarTodosNinguno"
android:text="Seleccionar / Deseleccionar todo" />
</LinearLayout>
And here it is the layout for the list's contents:
<?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="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:orientation="vertical" >
<TextView
android:id="#+id/rowTextView"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:padding="10dp"
android:textSize="16sp"
android:textStyle="bold"/>
<TextView
android:id="#+id/rowTextView2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:padding="10dp"
android:textSize="16sp"
android:textStyle="italic"/>
</LinearLayout>
<CheckBox
android:id="#+id/CheckBox01"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:focusable="false"
android:padding="10dp" />
</RelativeLayout>

Do not make the buttons View.INVISIBLE. Make the buttons View.GONE. There are three visibility states:
visible (normal)
invisible (pixels not drawn, but still takes up space)
gone (not included in rendering)

In the java code
yourView.setVisibility(View.GONE);
and in the XML code
android:visibility="gone"
Thier are 3 state
visible: normal
invisible : takes space and invisible
gone : no space and no visibility

Use
android:layout_height="0dp"
android:layout_weight="1"
In addition to #CommonsWare's answer
You should use a layout that fits well in all screen sizes. If you give you layout a fixed height like android:layout_height="376dp" it will look good only on the device (or emulator) you're testing on. What you have to do is to make sure that your listview takes up all (and only) the space left by your buttons.
Check out this article and this answer to better understand layout weights.

for hiding your widget
yourEditText.setVisibility(View.GONE)
for visbility of your widget
yourEditText.setVisibility(View.VISIBLE)

Problems with RelativeLayout

I separated the interface of my app in three areas: header, content and footer.
The header has a fixed size (it has only one image), while the footer and content have sizes that can vary.
In devices with higher resolutions I thought to insert the header and footer on the screen, and reserve any free space for the content area.
In devices with low resolutions thought of putting the content length as little as possible (something like wrap_content) and insert the footer below (requiring the user to perform scroll to view the footer).
The best I got was using RelativeView:
<RelativeLayout
android:id="#+id/relativeLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="#+id/header"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_alignParentTop="true" >
(...)
</LinearLayout>
<LinearLayout
android:id="#+id/footer"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_alignParentBottom="true" >
(...)
</LinearLayout>
<FrameLayout
android:id="#+id/content"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/footer"
android:layout_below="#+id/header"
android:lay >
(...)
</FrameLayout>
</RelativeLayout>
For resolutions larger works as expected, the problem is that for small resolutions: the content is less than it should, because it takes the space between the header and footer.
How can I solve the problem?
I could not find another way to get content assuming all the free space of the screen (in large resolutions), because I can not simply use fill_parent, since the content is between the header and footer.
I also tried using min-height, but without success.

Top level RelativeLayout layout_height make that fill_parent.
Then FrameLayout remove the layout_above property, just saying it's below the header should be enough.
Finally, FrameLayout may be causing the problem as it's normally used when only 1 element is on the screen and it fills the screen. Try replacing this with a LinearLayout. I've done something exactly like what you want in one of my apps, the layout is (keep in mind in my case I swap out the FrameLayouts for Fragments which are LinearLayout or RelativeLayout based.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mainBack"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/transparent" >
<FrameLayout
android:id="#+id/headerFrag"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="#+id/homeAdMsgFrag"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" />
<ListView
android:id="#+id/contactList"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#id/homeAdMsgFrag"
android:layout_alignParentLeft="true"
android:layout_below="#id/headerFrag"
android:background="#color/transparent"
android:cacheColorHint="#color/transparent" >
</ListView>
</RelativeLayout>

Some days before I also faced this issue, to solved what I did that I created Header.xml and footer.xml and included this two xml in my all others activities xmls because this two are common in all others activities.
To meet global resolution issue, I used weightsum and weight, applying weight will fixed your header and footer area and content area too.
This way I done in my one of project to resolve this issue, just try it, hope it will works for you.
EXAMPLE
<LinearLayout
android:weightSum="10"
android:orientation="vertical"
android:id="#+id/relativeLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="#+id/header"
android:layout_width="fill_parent"
android:layout_weight="2"
android:layout_height="0dp"
android:orientation="vertical" >
(...)
</LinearLayout>
<FrameLayout
android:id="#+id/content"
android:layout_width="fill_parent"
android:layout_weight="6"
android:layout_height="0dp">
(...)
</FrameLayout>
<LinearLayout
android:id="#+id/footer"
android:layout_width="fill_parent"
android:layout_weight="2"
android:layout_height="0dp"
android:orientation="vertical" >
(...)
</LinearLayout>
</LinearLayout>
Thanks.

Unable to populate listview with custom rows when component is above listview

I'm having issues with a ListView using custom rows that are loaded from a database.
If, for the list screen, I place a button above the ListView, no visible rows appear in the listview.
However as soon as I remove the button, everything works fine. I want the button (or any other component) to appear above to make it more user friendly. Attached are the two code samples below.
This is the XML file of the ListView Activity that works:
<?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"
android:background="#color/real_red_dark">
<LinearLayout
android:id="#+id/llMain"
android:layout_height="fill_parent"
android:background="#drawable/real_background"
android:layout_width="fill_parent"
android:layout_gravity="center"
android:gravity="center">
<ListView
android:id="#+android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/llButton"
android:layout_alignParentLeft="true" />
<TextView
android:id="#+android:id/empty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="#string/no_sessions"
android:textStyle="bold"
android:textSize="18dp"
android:gravity="center"/>
</LinearLayout>
</LinearLayout>
However, if I have the Button added above it, it will not show whatsoever:
<?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"
android:background="#color/real_red_dark">
<LinearLayout
android:id="#+id/llMain"
android:layout_height="fill_parent"
android:background="#drawable/real_background"
android:layout_width="fill_parent"
android:layout_gravity="center"
android:gravity="center">
<Button
android:id="#+id/btnSearch"
android:layout_width="fill_parent"
android:layout_height="35dip"
android:layout_gravity="center_horizontal"
android:layout_marginTop="3dip"
android:layout_marginLeft="15dip"
android:layout_marginRight="15dip"
android:text="Find Sessions"
android:textStyle="bold" />
<ListView
android:id="#+android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_below="#+id/llButton"
android:layout_alignParentLeft="true" />
<TextView
android:id="#+android:id/empty"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="#string/no_sessions"
android:textStyle="bold"
android:textSize="18dp"
android:gravity="center"/>
</LinearLayout>
</LinearLayout>

You could try adding the button programmatically as a header view in the listview itself, rather than in the xml layout.
use listView.addHeaderView(View)
http://developer.android.com/reference/android/widget/ListView.html#addHeaderView(android.view.View)

It is better if you use RelativeLayout than LinearLayout,it is also recommended by the android docs.Try to use android:layout_height value as "wrap_content" for ListView and TextView(which you may use to indicate for empty rows),it may help to you.

Something which doesn't look right but I'm assuming it's just a typo in the above...
android:id="#+android:id/list"
...there shouldn't be a + between # and android:. Using #+ is for adding a new resource id of your own, i.e., #+id:. You're also doing the same thing for the TextView...
android:id="#+android:id/empty"
Another thing but not sure it's relevant is you're specifying...
android:layout_below="#+id/llButton"
...I doubt it's the problem as android:layout_below isn't valid for a LinearLayout (it's for RelativeLayout) but there isn't a Button with the id of llButton in your layout. If there was, the + would also be incorrect as you should be specifying an existing id.
Not sure if amending the above would fix things but it could just be that the layout inflation is coming out 'wrong' due to those issues.

How to create fixed footer in android layout?

I am using following code to display button at the bottom of activity.
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
>
<Button android:id="#+id/btnGetMoreResults"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="Get more"
/>
</RelativeLayout>
and listview above it. when i display more data in listview this button pannel is moved down.can any one guide me how can i fix it at the bottom of activity?
any help would be appreciated.

The answer selected as correct is faulty, the button will hide the lower part of the list view. The correct way is to declare the button first and position the list above the button.
<Button android:id="#+id/btnGetMoreResults"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="Get more"
android:layout_alignParentBottom="true"/>
<ListView
...
android:layout_above="#id/btnGetMoreResults"/>

The android:layout_alignParentBottom attribute has to be declared in an element of the RelativeLayout not in the RelativeLayout himself (unless there is another RelativeLayout as a parent).
You should do something like this, with the ListView inside the RelativeLayout also :
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true">
<ListView ...>
<Button android:id="#+id/btnGetMoreResults"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="Get more"
android:layout_alignParentBottom="true" />
</RelativeLayout>

If you had, for example, all the scrollable elements in a ScrollView, you should do like the following:
<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"
style="#style/rootElement"
>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<!-- texts, buttons, images and anything that you want to scroll -->
</ScrollView>
<LinearLayout
android:orientation="vertical"
style="#style/footer"
android:id="#+id/footer"
android:layout_alignParentBottom="true"
>
</LinearLayout>
</RelativeLayout>
Note that if you want the footer to be fixed, then you shouldn't put it in the ScrollView, where the scrollable content will be placed. Make it child of RelativeLayout and set layout_alignParentBottom to true. Maybe you'll need to add a padding at the bottom of the ScrollView in this case (so that the last element do not get hidden by the footer).
The idea is similar for elements other than ScrollView