Develop Reference

How to set the initial ListView item background color with a selector

I cannot wrap my head around this, I want to set the initial background color of my list view items to grey, but they only take the right background color after I have selected them (and deselected) the first time. Which attributes are not configured properly in the first item definition?
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_selected="false" android:state_pressed="false" android:drawable="#color/grey" />
<item android:state_pressed="true" android:drawable="#color/red"/>
</selector>
Also tried to set the background of the list view item directly, but then the selector does not have any effect anymore.

For list items define a selector drawable:
res/drawable/list_item_background.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:state_enabled="true" android:state_pressed="true" android:drawable="#color/red" /> <!-- Pressed state -->
<item android:state_enabled="true" android:state_focused="true" android:drawable="#color/black" /> <!-- Focused state -->
<item android:state_enabled="true" android:state_selected="true" android:drawable="#color/orange" /> <!-- Selected state -->
<item android:drawable="#color/gray" /> <!-- Default state -->
</selector>
Set the above drawable as background for individual list item:
res/layout/list_item.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="?android:attr/listPreferredItemHeight"
android:background="#drawable/list_item_background" >
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/listitem" />
</LinearLayout>
Use the above custom layout for creating the list items:
String[] mStrings = {"One", "Two", "Three", "Four"};
ListView list = (ListView) rootView.findViewById(R.id.list);
list.setAdapter(new ArrayAdapter<String>(this.getActivity(), R.layout.list_item, R.id.listitem ,mStrings));

I would suggest trying with the following definition:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="#color/red"/>
<item android:drawable="#color/grey" />
</selector>
State List Drawables try matching in order. If you want a "default" drawable for many cases, it should be the last one, with no state flags. From docs:
During each state change, the state list is traversed top to bottom
and the first item that matches the current state is used—the
selection is not based on the "best match," but simply the first item
that meets the minimum criteria of the state.

Also tried to set the background of the list view item directly, but then the selector does not have any effect anymore.
If I am not mistaken, selector is drawn behind the list item(by default). Since you set solid grey color to your list item, the red color from the selector doesn't show. You can confirm this by changing the way you have defined #color/grey - try adding a low alpha value to it. In this case the red color should come through.
You can of course change this behavior by setting android:drawSelectorOnTop="true" - default is false. The list item will however be hidden when the selector is drawn on top.
Anyway - from what you have said, you want the items to have #color/red background when pressed and #color/grey background otherwise.
See if the following satisfies your requirements:
Selector drawable for list item views:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="#android:color/transparent"/>
<item android:drawable="color/grey" />
</selector>
For the listSelector attribute, only provide the color value:
<ListView
....
....
android:listSelector="#color/red" >
</ListView>
In a few words, the item background color is transparent when the list item is pressed - allowing the listSelector red color to be visible. In all other cases, the grey color is visible.

You need to create a listselector.xml under your drawable folder
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:state_selected="false"
android:state_pressed="false"
android:drawable="#drawable/gradient_bg" />
<item android:state_pressed="true"
android:drawable="#drawable/gradient_bg_hover" />
<item android:state_selected="true"
android:state_pressed="false"
android:drawable="#drawable/gradient_bg_hover" />
</selector>
Then inside your listview add :
<ListView
android:id="#+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:divider="#b5b5b5"
android:dividerHeight="1dp"
android:listSelector="#drawable/listselector" />

The selector should be similar to the one below:
List_selector.xml
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:state_selected="false"
android:state_pressed="false"
android:drawable="#drawable/gradient_bg" />
<item android:state_pressed="true"
android:drawable="#drawable/gradient_bg_hover" />
<item android:state_selected="true"
android:state_pressed="false"
android:drawable="#drawable/gradient_bg_hover" />
</selector>
Then in the drawables folder, you need to create the following 2 files:
gradient_bg.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient
android:startColor="#cfcfcf"
android:centerColor="#737374"
android:endColor="##3e3e3e"
android:angle="270" />
</shape>
gradient_bg_hover.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient
android:startColor="#7f0000"
android:centerColor="#660000"
android:endColor="#4c0000"
android:angle="270" />
</shape>
Finally, in the listview, you need to add the following line of code:
android:background="#drawable/list_selector"
Hope this helps :)

Selector drawables

I have the following definition of an android style and selector applied to ListView, however I see no effect of gray gradient applied when I click on it. On click it immediately displays blue gradient.
As author of this example has written:
We want to apply this to our list selector. Instead of always showing
the same gradient, we want the gradient to change its start color from
grey to a light blue whenever a list item is pressed. Because we now
have two different list selectors—one for default state one for
pressed state—we need to keep them in separate files.
Can someone explain how it should be displayed properly ? Or I'm missing something ?
More general, what exactly I should expect to see on display screen ? Something like fluent transition from gray gradient to blue gradient on list item click ?
Update: this is how author 'sees' it, but when I click on item it looks only like on right side of picture. May I assume that author wants to see all items in list to be gray by default ? Or this state is not applicable to list view items ?
list_item_default.xml -> GRAY GRADIENT
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<gradient
android:angle="0"
android:endColor="#FFFF"
android:startColor="#AFFF" />
<stroke
android:width="1dip"
android:color="#CCC" />
<corners android:radius="5px" />
</shape>
list_item_pressed.xml -> BLUE GRADIENT
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<gradient
android:angle="0"
android:endColor="#FFFF"
android:startColor="#AA66CCFF" />
<stroke
android:width="1dip"
android:color="#CCC" />
<corners android:radius="5px" />
</shape>
list_selector.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#drawable/list_item_default" android:state_pressed="false"/>
<item android:drawable="#drawable/list_item_pressed" android:state_pressed="true"/>
</selector>
styles.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="MyMoviesTheme" parent="#android:style/Theme.Black">
<item name="android:listViewStyle">#style/MyMoviesListView</item>
<item name="android:windowBackground">#drawable/film_bg</item>
</style>
<style name="MyMoviesTextAppearance" parent="#android:style/TextAppearance">
<!--<item name="android:textStyle">bold</item>-->
</style>
<style name="MyMoviesListView" parent="#android:Widget.ListView">
<item name="android:background">#color/list_background</item>
<item name="android:listSelector">#drawable/list_selector</item>
<item name="android:cacheColorHint">#android:color/transparent</item>
<item name="android:fastScrollEnabled">true</item>
<item name="android:footerDividersEnabled">false</item>
</style>
</resources>

Try adding a sentence：
<item
android:state_enabled="true"
android:drawable="#drawable/list_item_default"/>
<item
android:state_enabled="true"
android:drawable="#drawable/list_item_pressed"
android:state_pressed="true"/>

ListView item color in XML file

I am using the Xamarin sample at the following link:
Part 3 - Customizing a ListView's Appearance
The sample code is from the following file: CustomRowView.zip
Here is a screenshot of my running code: Emulator screenshot
The background color of the ListView items are in yellow.
May I please have some help to change this color to be the default color, or to choose this color?
I am not sure where to find this in code. I have looked in the XML layout files, but cannot find the correct item.
In the RelativeLayout, there is a reference to the following:
android:background="#drawable/CustomSelector"
And this is the contents of the file:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="false"
android:state_selected="false"
android:drawable="#color/cellback" />
<item android:state_pressed="true" >
<shape>
<gradient
android:startColor="#E88A93"
android:endColor="#E88A93"
android:angle="270" />
</shape>
</item>
<item android:state_selected="true"
android:state_pressed="false"
android:drawable="#color/cellback" />
</selector>
Is this code relevant to the question?
Thanks in advance

The "yello background color" is the custom listview item's background color. In the toturial you referenced, you can find it in "/Resources/Layout/CustomView.axml" :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#FFDAFF7F"
android:padding="8dp">
<LinearLayout android:id="#+id/Text"
android:orientation="vertical"
...
...
android:layout_height="48dp"
android:padding="5dp"
android:src="#drawable/icon"
android:layout_alignParentRight="true"
/>
</RelativeLayout >
the android:background="#FFDAFF7F" is what you want to modify.

Your ListView is using CustomView.axml for each row. in CustomView.axml parent element (RelativeLayout) is using CustomSelector.xml from Drawable folder in android:background attribute. In this file you can change colors of three states (pressed, pressed & selected, none) as you wish.

Create a color.xml in your values file and defines your color(which color you wnt to set to your listview ite) here
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="magenta">#FF00FF</color>
<color name="yellow">#FFFF00</color>
<color name="light_grey">#ffb9b8bb</color>
</resources>
and then use these colors in your custom selector
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#color/light_grey" android:state_pressed="false" android:state_selected="false"/>
<item android:state_pressed="true"><shape>
<gradient android:angle="270" android:endColor="#E88A93" android:startColor="#E88A93" />
</shape></item>
<item android:drawable="#color/light_grey" android:state_pressed="false" android:state_selected="true"/>
</selector>

I never get it yellow, which should come after pressing an item in the list.
(I changed your sample to yellow for state_pressed=true.
Tks
Seli
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#color/light_grey" android:state_pressed="false" android:state_selected="false"/>
<item android:state_pressed="true">
<shape>
<gradient android:angle="270" android:endColor="#E88A93" android:startColor="#E88A93" />
</shape>
</item>
<item android:drawable="#color/yellow" android:state_pressed="false" android:state_selected="true"/>
</selector>

Is it possible to create an xml subclass of a state list selector?

For example, say I have a color state list declared in XML, called example1.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:color="#color/red"
android:state_pressed="true" />
<item
android:color="#color/blue"
android:state_checked="true" />
<item
android:color="#color/green"
android:state_disabled="true" />
<item
android:color="#color/orange" />
</selector>
Then, I want to create example2.xml and I want it to be the exact same as example1.xml except I want the pressed color to be purple instead of red:
<item
android:color="#color/purple"
android:state_pressed="true" />
So example2.xml would end up acting like this:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:color="#color/purple" <-- note this value is different
android:state_pressed="true" />
<item
android:color="#color/blue"
android:state_checked="true" />
<item
android:color="#color/green"
android:state_disabled="true" />
<item
android:color="#color/orange" />
</selector>
but without all of the duplicate code. Also, if I want to change a color I can just change it in one place.
Is this possible?

I don't think you can do this on Android, You have to create multiple xml resources for different selector.

How to change the background color of the toggle button on Android

I tried to change the background color of the toggle button using XML file as white color, but the toggle button is totally damaged. It looks like all the button was covered with white.
There is no indication of ON or OFF on the toggle button when I have changed the color of the toggle button to white. Is there is another way to change the background which will not damage the indication of the toggle button?
<ToggleButton android:id="#+id/togglebutton"
android:layout_width="100px"
android:layout_height="46px"
android:background="#ffffff"
android:layout_above ="#+id/save"
android:textOn="DAY"
android:textOff="NIGHT" />
This is how my XML code look for the toggle button.

Yes, there is a way to change the background as you wish, but you have to use a selector like this as background:
<selector
xmlns:android="http://schemas.android.com/apk/res/android"
>
<item
android:state_focused="true"
android:state_pressed="false"
android:drawable="#drawable/some_image" />
<item
android:state_focused="true"
android:state_pressed="true"
android:drawable="#drawable/some_other_image" />
<item
android:state_focused="false"
android:state_pressed="false"
android:drawable="#drawable/some_image1" />
<item
android:state_focused="false"
android:state_pressed="true"
android:drawable="#drawable/other_image" />
</selector>
For #Drawable, etc. (you can use a color or make a gradient. Check this for more information about gradients.

Follow this way to make your ToogleButton have background color red when On and green when OFF
First, create tooglebutton_selector.xml in drawable folder
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#drawable/togglebutton_on"
android:state_checked="true" />
<item android:drawable="#drawable/togglebutton_off"
android:state_checked="false"
/>
</selector>
Second, create togglebutton_on.xml in drawable folder
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid
android:color="#ff0000" /> // red color
</shape>
Third, create togglebutton_off.xml in drawable folder
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid
android:color="#00FF00" /> // green color
</shape>
Finally, in your ToggleButton
<ToggleButton
android:id="#+id/btnMon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#drawable/tooglebutton_selector" //set background of ToggleButton to tooglebutton_selector
/>

When you decompile your SystemUI.apk, you should go to the following file: SystemUI/res/values/colors.xml
Then change the following line:
#ff000000
#ffffffff
#80000000
#ffadc1d6
#ffffffff
#ffe6e6e6