Develop Reference

android:Theme.Material.Light requires API level 21 (current min is 8)

I want to use Material Theme in my application which has minimum sdk version of 8. As per docs - "The material theme is only available in Android 5.0 (API level 21) and above. The v7 Support Libraries provide themes with material design styles for some widgets and support for customizing the color palette." Does it mean I can use it if I add v7 Support Libarary in my project? Because after adding this library I got the following error:
android:Theme.Material.Light requires API level 21 (current min is 8).
Or maybe I understood something wrong? Any suggestion will be appreciated. Thanks in advance.

For this you need to have 2 values folders.
One that exists by default, and another, you have to create in your res folder and name it values-v21.
In the default values folder, in styles.xml, use a theme other than Material theme.
And in the styles.xml of values-v21 folder that you created, use Material theme.
Android phone will automatically pickup the styles.xml which it supports. If the phone supports Material Design (Lollipop devices), your app will use Material theme (values-21 folder).
If it doesn't (in phones running older Android versions), the default values folder will be used.

You need to use android:theme="#style/Theme.AppCompat.Light" theme to get a material design.
Make sure your min is 8 and your target is 21. And you're using build tools/sdk 21.

Pedro Oliveira is right with regards to Theme.AppCompat, but some essential information is missing in that answer.
A blog post titled appcompat v21: material design for pre-Lollipop devices! by Chris Banes from the Android team probably best answers the question of how to get Material Theme for API levels prior to 21.
To summarise, you need appcompat-v7 dependency:
dependencies {
...
compile "com.android.support:appcompat-v7:21.0.3"
}
After that, for dark version as your base theme, use:
<style name="AppTheme" parent="Theme.AppCompat">
</style>
And for light version:
<style name="AppTheme" parent="Theme.AppCompat.Light">
</style>
And if you're new to AppCompat, there are things you need to know, such as:
All of your Activities must extend from ActionBarActivity*. It extends
from FragmentActivity from the v4 support library, so you can continue
to use fragments.
*NB: more recently, ActionBarActivity has been deprecated in favour of AppCompatActivity.
But you really should read the whole Setup section of that blog post! (The information on Toolbar vs Action Bar, and some of the comments are also something you probably shouldn't miss.)

In your NameActivity.java file import the following:
import android.support.v7.widget.Toolbar;
Comment the previous one:
//import android.widget.Toolbar;
With this the problem is solved.

Properly set SeekBar style for Holo and pre-Holo APIs

After setting SeekBar with Holo style, I got warning that it's not supported pre-Holo APIs.
If I leave it this way, will this crash the app or pull pre-Holo style anyway? It does not crash on the emulator and I don't have 2.3.3 device.
The reason for asking his is odd behaviour. I tried to manually set style for Holo and pre-Holo using res/values-v11/ directories and placing styles.xml in each and setting the style of SeekBar to style="#style/settings_seekbar" .
Style for API 11+ looked like this
<style name="settings_seekbar">
<item name="android:seekBarStyle">#android:style/Widget.Holo.SeekBar</item>
</style>
and style for APIs older than 11 looked like this
<style name="settings_seekbar">
<item name="android:seekBarStyle">#android:style/Widget.SeekBar</item>
</style>
So it looked like this would work. But on either device with Android 4.0+, I don't see Holo's theme, but the old thick-yellow theme.
If this is the proper way of settings styles (in case the first solution will crash a device), where did I make a mistake thus Holo theme never appeared on newer devices?

It seems we can safely use a theme from the upper SDK because I found no indicators that it will ever crash the app.
If the theme does not exist, Android will use the appropriate lower-level theme.
The error we can see on the image is just a warning that UI will not look the same in the SDKs which do not support this theme.

Android custom actionbar overlay

So i have been following the tutorials on the android developer website. i have created an android project with min SDK of 8, and included the compatibility for the android 2.1 for the menu bar. i am able to get the menu bar to work properly for android 4.0 and 2.2, no issues.
now i am trying to set the overlay for the menubar, and i ran into an issue. while setting up a custom theme with the parent being an AppCompact theme, as stated here http://developer.android.com/training/basics/actionbar/overlaying.html .
the code with the issue is :
<!-- the theme applied to the application or activity -->
<style name="CustomActionBarTheme"
parent="#android:style/Theme.AppCompat">
<item name="android:windowActionBarOverlay">true</item>
<!-- Support library compatibility -->
<item name="windowActionBarOverlay">true</item>
</style>
2 issues arise:
error: Error retrieving parent for item: No resource found that
matches the given name '#android:style/ Theme.AppCompat'.
and
android:windowActionBarOverlay requires API level 11 (current min is
8)
the first issue, i have no idea why it is being thrown. i use Theme.AppCompact in my manifest and it works. the 2nd issue is confusing me, in the google tutorials it states to include both definitions, as one is for android devices with the new API and the other is for older API's.
i have tried to clean/build my project, it did not help.

Solved by replacing
parent="#android:style/Theme.AppCompat"
with
parent="#style/Theme.AppCompat"

How to remove Menu Option in Android 4.2.2

My Android App has min sdk and target sdk set to 10, when I run my app on Nexus 4 -Android Version 4.2.2, it shows a menu option button beside the system navigation.
I am not using menu options in my app and I dont want to show the user this useless menu option. How can I remove it ?
I have read about this on http://android-developers.blogspot.com.au/2012/01/say-goodbye-to-menu-button.html but I do not get a concrete solution.
Attached is the image :
I dont want to change the sdk version for my app. Is it possible to remove menu option without changing sdk version?

You simply have to modify your targetSdk to something above 10. For instance, if you use last SDK you should use targetSdk=16

The concrete solution is in the article:
Add theme to your application:
<application android:theme="#style/NoActionBar">
Then define this theme for pre-Honeycomb in res/values/themes.xml:
<resources>
<style name="NoActionBar" parent="#android:style/Theme">
<!-- Inherits the default theme for pre-HC (no action bar) -->
</style>
</resources>
and for Honeycomb and later:
<resources>
<style name="NoActionBar" parent="#android:style/Theme.Holo.NoActionBar">
<!-- Inherits the Holo theme with no action bar; no other styles needed. -->
</style>
</resources>

If you set your target SDK version to 11 and below, the android legacy menu button will appear. But just in case you want to keep that target SDK version, you can just delete the method onCreateOptionsMenu, this way you won't inflate any options.

Difference between pre ICS and post ICS Holo theme related

I have a couple of app that were created with Android 1.6 and after. The problem is when I run these app on recent Android (device or simulator) like ICS, I don't have the Holo theme.
I know i can find a lot of thread on how to specify the theme but when I create a new app now, I have the new theme without any lines of code.
I don't want to have ICS theme on all android version, just ICS theme on ICS, like new holo buttons style on ICS and old grey style for older. Now I just have grey buttons for all versions.
I can create new empty projects and copy all my files into it but there must be a hidden value somewhere to chenge this.
In my manifest I have:
<uses-sdk android:minSdkVersion="3" />
<uses-sdk android:targetSdkVersion="14" />
What can be the difference between old and new created projects ?

What I'm understanding is that you want your app to switch between the legacy (classic) theme and the new Holo theme based on API version.
First, in your values (res/values) folder make a new xml. Call it styles.xml. It should contain these lines:
<resources>
<style name="AppTheme" parent="#android:style/Theme.Black"/>
</resources>
Then make a new folder in res called values-v11. In this new folder make another new xml. Also name it styles.xml This file should contain these lines:
<resources>
<style name="AppTheme" parent="#android:style/Theme.Holo"/>
</resources>
Then in your AndroidManifest.xml you Application node should contain this line:
android:theme="#style/AppTheme"
Now on devices with Honeycomb or higher you get the Holo theme and for everything else, you get the old classic theme. You can easily experiment with this to suit your needs - this is the general way to switch between themes based on API version.