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Change button background when pressed

I want to change background of a button when it is clicked. I tried to use a selector. But It didn't work. Here is the selector (add_grp_slctr.xml):
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:state_focused="true" android:drawable="#drawable/add_grp_d"/>
<item android:state_pressed="true" android:drawable="#drawable/add_grp_d" />
<item android:drawable="#drawable/add_grp" />
</selector>
And the button :
<Button
android:id="#+id/addGrpBtn"
android:layout_width="55dp"
android:layout_height="45dp"
android:layout_gravity="center"
android:background="#drawable/add_grp_slctr"
android:onClick="addGrpDialogOpen" />
add_grp_d and add_grp are images(png).

I tried a similar code which will be white by default, black when pressed on an onclick of a button:
//***This is the btn_selector which is to be declared in drawable folder***
<?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/black" /> <!-- pressed -->
<item android:drawable="#android:color/white" /> <!-- default -->
</selector>
and called this on the button.xml -->
android:background="#drawable/btn_selector"
Hope this would help..:)

go through the http://developer.android.com/guide/topics/resources/drawable-resource.html#StateList once. Also state_focussed for button only works when you are focussing the button using a hardware-keyboard.
As for your case
<?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="#drawable/button_default"/>
<item android:state_pressed="true" android:state_selected="false" android:drawable="#drawable/button_default" />
<item android:state_pressed="false" android:state_selected="true" android:drawable="#drawable/button_selected"/>
<item android:state_pressed="true" android:state_selected="true" android:drawable="#drawable/button_selected" />
<item android:drawable="#drawable/button_selected" />
</selector>

Use your selector
change your code like this
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:state_focused="true" android:drawable="#drawable/add_grp_d"/>
<item android:state_pressed="true" android:drawable="#drawable/add_grp" />
<item android:drawable="#drawable/add_grp_d" />
</selector>
My Code
<item android:drawable="#drawable/shadow_design_click" android:state_pressed="true"/>
<item android:drawable="#drawable/shadow_design" android:state_focused="true"/>
<item android:drawable="#drawable/shadow_design"/>
</selector>

I think you should change your selector a bit.
Check this answer here.

Instead of passing cuastom XML file, if you just want to change the color of you button then you can try with the following way.
Button lineColorCode = (Button)findViewById(R.id.button1);
Now inside button's click event use following code.
int color = Color.parseColor("#AE6118"); //The color u want
lineColorCode.setColorFilter(color);

<item> tag requires a 'drawable' attribute

I am trying to very simply style a Button. I just want it blue with with text when not pressed, and white with blue text when clicked.
I tried to do this with a style and a selector.
In my layout I have this Button:
<Button
android:id="#+id/button1"
style="#style/MyButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#string/login" />
And in res/values/styles I have this styles.xml:
<style name="MyButton">
<item name="android:background">#drawable/btn_background</item>
<item name="android:textColor">#drawable/btn_textcolor</item>
</style>
And of course, the two selectors, in res/drawable, btn_background.xml:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:state_pressed="true" android:color="#color/white" />
<item android:color="#color/SapphireBlue" />
</selector>
and btn_textcolor.xml:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:state_pressed="true" android:color="#color/SapphireBlue" />
<item android:color="#color/white" />
</selector>
The error I get now when I either run the app, or open the layout editor is:
<item> tag requires a 'drawable' attribute
I understand the message, but I don't have a drawable, is it is a simple, flat button.
How can I create such a simple button?
Update according to this post, it should work.

Try this way,hope this will help you to solve your problem.
btn_background.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="#color/white" android:state_pressed="true"></item>
<item android:drawable="#drawable/white" android:state_focused="true"></item>
<item android:drawable="#drawable/SapphireBlue" android:state_enabled="true" android:state_focused="false" android:state_pressed="false"></item>
<item android:drawable="#drawable/white" android:state_enabled="false"></item>
</selector>
btn_textcolor.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:color="#color/SapphireBlue" android:state_pressed="true"></item>
<item android:color="#drawable/SapphireBlue" android:state_focused="true"></item>
<item android:color="#drawable/white" android:state_enabled="true" android:state_focused="false" android:state_pressed="false"></item>
<item android:color="#drawable/SapphireBlue" android:state_enabled="false"></item>
</selector>

Background attribute expects a drawable and the drawable selector must be in one of the /drawable folders.
TextColor attribute expects a color and the color selector must be in one of the /color folders.
/res/color/my_textcolor_selctor.xml
/res/drawable/my_background_selector.xml
Also, the drawable selector must use 'android:drawable' for selector items (a color resource maybe used for the attribute value since a color is a drawable),
whereas the color selector must use 'android:color' for the selector items.
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false"
android:drawable="#color/disabledbackgroundColor" />
<!-- default -->
<item android:drawable="#color/myBackgroundColor" />
</selector>
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false"
android:color="#color/disabledColor" />
<!-- default -->
<item android:color="#color/defaultColor" />
</selector>

android:background seems to accept drawable selectors but not color selectors... so just leave a color as your android:background, and use a normal color selector with android:backgroundTint, which expects colors anyway:
at styles.xml:
<style name="MyButton">
<item name="android:background">#color/some_fixed_color</item>
<item name="android:backgroundTint">#color/background_color_selector</item>
<item name="android:textColor">#drawable/btn_textcolor</item>
</style>
(res/color/background_color_selector.xml is a normal color selector.)

selector disable botton

I have this selector for one of my button's background
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="false"
android:drawable="#drawable/bg_botton_disable"/>
<item android:state_pressed="true"
android:state_enabled="true"
android:drawable="#drawable/bg_botton_pressed"/> <!-- pressed -->
<item android:state_enabled="true"
android:drawable="#drawable/bg_botton" /> <!-- default -->
</selector>
(Button) bt = (Button) findviewById(R.id.MyBotton);
bt.setEnabled(false);
The code disables the functionality of my button. I mean when I press the button it doesn't launch its own onClick() method. That's fine, but the problem is that it doesn't change the background of the button to bg_botton_disable drawable.
Does anyone has any suggestion how to fix it?

Reorder your selector items
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_enabled="true"
android:drawable="#drawable/bg_botton" /> <!-- default -->
<item android:state_pressed="true"
android:drawable="#drawable/bg_botton_pressed"/> <!-- pressed -->
<item android:state_enabled="false"
android:drawable="#drawable/bg_botton_disable"/>
</selector>

What is the state of a spinner when it's displaying a drop down list?

I am creating a spinner with a custom view, anyway I managed to show different drawables for when the spinner is inactive and also for when it's pressed, I would like to keep the pressed state drawable when the dropdown list shows. Here is mi XML file:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_focused="true"
android:state_pressed="false"
android:drawable="#drawable/ComboBoxInactive" />
<item android:state_focused="true"
android:state_pressed="true"
android:drawable="#drawable/ComboBoxActive" />
<item android:state_focused="false"
android:state_pressed="true"
android:drawable="#drawable/ComboBoxActive" />
<item android:drawable="#drawable/ComboBoxInactive" />
</selector>
what state should I add for when it is displaying the dropdown? I want it to display ComboBoxActive drawable. I already tried adding this:
<item android:state_enabled ="false"
android:drawable="#drawable/ComboBoxActive"/>
Any idea of what the state is?

There is no android:state_dropdown_showing state.
The only one state on spinner dropdown list is state_enabled="true"
You can use my selector to differentiate dropdown list state
<?xml version="1.0" encoding="UTF-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- disabled state -->
<item android:state_enabled="false" android:drawable="#drawable/spinner_off"/>
<!-- pressed state -->
<item android:state_enabled="true" android:state_window_focused="true" android:state_pressed="true" android:drawable="#drawable/spinner_pressed"/>
<!-- unselected state -->
<item android:state_enabled="true" android:state_window_focused="true" android:drawable="#drawable/spinner_default"/>
<!-- dropdown list state -->
<item android:state_enabled="true" android:state_focused="true" android:drawable="#drawable/spinner_dropdown_list_is_shown"/>
<!-- default -->
<item android:drawable="#drawable/spinner_default"/>
</selector>
Don't forget to set setFocusable and setFocusableInTouchMode properties on spinner.

Based on Olef Koshkin answer I can add that if you want save changed state after click to spinner and return it to default only after close spinner you can use. It works for me.
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- disabled state -->
<item android:drawable="#drawable/custom_spinner_inactive"
android:state_enabled="false"/>
<!-- pressed state -->
<item android:drawable="#drawable/custom_spinner_inactive"
android:state_enabled="true"
android:state_pressed="true"
android:state_window_focused="true"/>
<!-- unselected state -->
<item android:drawable="#drawable/custom_spinner_inactive"
android:state_enabled="true"
android:state_window_focused="true"/>
<!-- dropdown list state -->
<item android:drawable="#drawable/custom_spinner_inactive"
android:state_enabled="true"
android:state_focused="true"/>
<!-- default -->
<item android:drawable="#drawable/custom_spinner_active"/>
</selector>
In other cases I see blink of default state and I didn't like it.

This works for me
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- For DropDown is Not Visible -->
<item android:drawable="#drawable/spinner_bg_with_arrow_border_theme_color" android:state_window_focused="false" />
<!-- For DropDown is enter code here Visible -->
<item android:drawable="#drawable/spinner_bg_with_arrow_border" android:state_window_focused="true" />
</selector>

selector for listview doesn't work

I want to set the color of row in listview if selected to yellow and otherwise be white so I use the following selector
<?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/encounter_normal" />
<item android:state_enabled="true"
android:state_focused="true" android:drawable="#color/encounter_normal" />
<item android:state_enabled="true"
android:state_selected="true" android:drawable="#color/encounterselector_color" />
<item
android:drawable="#color/encounter_normal" />
</selector>
where
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="encounterselector_color">#fbeda5</color>
<color name="encounter_normal">#ffffff</color>
</resources>
and I use it like the following
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:id="#+id/EncounterGrid"
android:background="#drawable/encounterlistview"
>
<!-- remaining code -->
but the row is always white , any idea how to fix that

Setting the background color with a selector is a bit tricky. Basically you have to create a drawable for each color and use them in your android:drawable attributes. You cannot directly use colors.
Check this related question for more details.

I use the following:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- This is the switched off state -->
<item android:state_enabled="false"
android:drawable="#drawable/grey_bar" />
<!-- These are the partial states -->
<item android:state_pressed="true"
android:drawable="#drawable/button_pressed" />
<item android:state_focused="true" android:state_enabled="true"
android:drawable="#drawable/button_focused" />
<!-- This is the switched on state -->
<item android:state_enabled="true"
android:drawable="#drawable/button_normal" />
</selector>
Where all of the drawables I point to are defined in xml, or are existing 9 patch images.

use android:color on your selector and not android:drawable because you are getting reference to the color resources, so your selector will be like this:
<?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:color="#color/encounter_normal" />
<item android:state_enabled="true"
android:state_focused="true" android:color="#color/encounter_normal" />
<item android:state_enabled="true"
android:state_selected="true" android:color="#color/encounterselector_color" />
<item
android:color="#color/encounter_normal" />
</selector>

Nothing was working for me until I set drawSelectorOnTop = "true".
Everything worked after that.