Android popup messages using Toast

In Android you can display pop up messages that lasts for a certain duration and then disappears-using the <strong>Toast </strong>class.<br /><br /><strong>Toast </strong>is a transient message that appears and disappears without any interaction from the user and with no notification to the program that it disappeared.<br /><br />the Toast can display a simple text message or a complex view.<br /><br /><strong><span style="font-size: large;">Displaying simple text:</span></strong><br /><br />to display a simple toast that displays a text message we use the following code:<br /><pre class="brush:java">Toast toast=Toast.makeText(this, "Hello toast", 2000);<br /> toast.setGravity(Gravity.TOP, -30, 50);<br /> toast.show();<br /></pre><br />we create the toast using the static <b>Toast.makeText(Context con,String message, int duration)</b> method to create a toast in the current context to display a text message for a duration specified in milli seconds or we can use the constant values <b>Toast.LENGTH_SHORT</b> to display for a short duration or <b>Toast.LENGTH_LONG</b> for longer duration.<br />The toast by default appears in the center of the screen, you can change the default position by specifying the Gravity and the X and Y offsets.<br />finally we call the <b>Show()</b> method to display the toast.<br /><br />the previous toast will be like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Toasts/toast1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" ox="true" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Toasts/toast1.png" width="225" /></a></div><br /><strong><span style="font-size: large;">Displaying complex views:</span></strong><br /><br /><br />Toasts can also display complex views. this is done like this:<br /><br /><strong>First: </strong>create a layout xml file in <strong>res/layout</strong> directory. the file must be named toast_layout.xml.<br /><pre class="brush:xml"><?xml version="1.0" encoding="utf-8"?><br /><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"<br /> android:orientation="vertical"<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@+id/toastView"<br /> ><br /><TextView <br /> android:layout_width="fill_parent" <br /> android:layout_height="wrap_content" <br /> android:text="Hello toast"<br /> android:textColor="#000"<br /> /><br /> <TextView <br /> android:layout_width="fill_parent" <br /> android:layout_height="wrap_content" <br /> android:id="@+id/txtDate"<br /> android:textColor="#000"<br /> /><br /> <br /> <br /></LinearLayout><br /></pre><br />then from the code<br /><pre class="brush:java">Toast toast=new Toast(this);<br /> LayoutInflater inflater=this.getLayoutInflater();<br /> View toastView=inflater.inflate(R.layout.toast_layout, (ViewGroup)findViewById(R.id.toastView));<br /> TextView txtDate=(TextView)toastView.findViewById(R.id.txtDate);<br /> txtDate.setText("toast appeared at "+Calendar.getInstance().getTime().toLocaleString());<br /> toast.setGravity(Gravity.CENTER, 0, 0);<br /> toast.setView(toastView);<br /> toast.show();<br /></pre><br />the toast will be like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Toasts/toast2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" ox="true" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Toasts/toast2.png" width="226" /></a></div><span style="color: red;">Notes:</span><br /><ul><li><span style="color: black;">In the toast_layout.xml width, if you put any buttons or any control that has a callback, it would appear disabled and the user cannot interact with it.</span></li><li>The toast can be created in two ways: by calling <strong>Toast.makeText </strong>method or by specifyinga view via <strong>setView </strong>method. when you want to display a simple text use the first one otherwise use the second. if you try to interchange or combie between the two methods an exception will be thrown.</li></ul>

In Android you can display pop up messages that lasts for a certain duration and then disappears-using the Toast class. Toast is a transient...

Using Themes and Styles in Android

<div dir="ltr" style="text-align: left;" trbidi="on">In web design we have the concept of Styles and Themes. Styles like Cascading Style Sheets (CSS) define the values of the web controls attributes such as width, heigth, font color, background and so on. A style can be applied on several controls in several web pages.<br /><br />Themes are used to group a set of styles to be applied on the whole web application. Themes (or sometimes skins) define the look of all control within the application.<br /><br />Android introduces similar concepts by using <strong>Styles</strong> and <strong>Themes. </strong>A Style can be applied to views individually while a Theme is applied to a whole activity.<br /><br /><strong><span style="font-size: large;">Styles:</span></strong><br /><br />Styles are defined as xml resources files in <strong>res/values</strong> directory of your project.<br /><br />consider this definition of a <strong>TextView:</strong><br /><pre class="brush:xml"><TextView android:layout_width="fill_parent" <br /> android:layout_height="wrap_content" <br /> android:textColor="#FFF" <br /> android:typeface="monospace" <br /> android:text="First Text View"<br /> android:background="#00F" <br /> /><br /><br /></pre><br />this defines a text view with width and height equal to wrap_content, white font color, font type "monospace" and blue back ground.<br /><br />if we want to have the same results using a style: we first create a xml file (call it styles.xml) in <strong>res/values</strong> directory and it would be like this:<br /><pre class="brush:xml"><?xml version="1.0" encoding="utf-8"?><br /><resources><br /><style name="BlueLabel"><br /><item name="android:layout_width">fill_parent</item><br /><item name="android:layout_height">wrap_content</item><br /><item name="android:typeface">monospace</item><br /><item name="android:background">#00F</item><br /><item name="android:textColor">#FFF</item><br /></style><br /></resources><br /></pre><br />then redefine the TextView like this:<br /><pre class="brush:xml"><TextView android:text="First Text View"<br /> style="@style/BlueLabel" / ><br /><br /></pre><br />and you will receive the same results.<br />the attributes in the <b><item></b>tag can be any layout property.<br /><br /><strong>Inheriting Styles:</strong><br />Styles in Android has an interesting feature which is the ability to inherit styles in a fashion similar to that in CSS. consider this example:<br /><br />we have a style for a button like this:<br /><pre class="brush:xml"><style name="ButtonStyle"><br /><item name="android:layout_width">wrap_content</item><br /><item name="android:layout_height">wrap_content</item><br /><item name="android:textSize">15px</item><br /><item name="android:typeface">serif</item><br /></style><br /><br /></pre><br />the button will appear like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Styles/styles1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" ox="true" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Styles/styles1.png" width="224" /></a></div><br />we can make this style inherit from <b>BlueLabel</b> defined previously by adding the <b>parent</b> attribute to the <b><style*gt;</b> tag:<br /><pre class="brush:xml"><style name="ButtonStyle" parent="BlueLabel"><br /></pre>then the button will be like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Styles/styles2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" ox="true" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Styles/styles2.png" width="226" /></a></div>the button inherited the background color from the parent style.<br />another interesting feature in styles inheritance is the ability to inherit from the platform built-in styles defined in the <b>android.R.style</b> namespace. to know more about the platform styles check this <a href="http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=core/res/res/values/styles.xml;h=d7b654e49809cb97a35682754b1394af5c8bc88b;hb=HEAD">link</a><br /><br />or you can type in your editor (Eclipse) android.R.style and let the intelli-sense list you the complete list of platform styles, if you want to use them in your xml just replace the undrscores with a period like this:<br />Widget_Button becomes @android:style/Widget.Button.<br /><br />In the previous button style example we will set the parent of the style to be <b>@android:style/Widget.Button.Small</b><br />and the button will be like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Styles/styles3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" ox="true" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Styles/styles3.png" width="225" /></a></div><br /><span style="color: red;">Note:</span> if you apply a style to a <b>ViewGroup</b> widget, it's child widgets <b>will not inherit</b> that style.<br /><br /><b><span style="font-size: large;">Using Themes</span></b><br /><br />you can apply styles as themes on an activity level or application level.<br /><br />if you apply a theme on an activity level then all widgets within that activity will inherit from that theme.<br />to do so, open the <strong>AndroidManifest.xml</strong> and go the <b><activity></b> tag and add the <b>android:theme</b> attribute:<br /><pre class="brush:xml"><activity android:name=".StylesDemo"<br /> android:label="@string/app_name" android:theme="@style/BlueLabel"><br /><br /></pre><br />to apply a theme on the application level so that the style will be applied to all activities within your application, open the <strong>AndroidManifest.xml</strong> and go the <b><application></b> tag and add the <b>android:theme</b> attribute:<br /><pre class="brush:xml"><application android:icon="@drawable/icon" android:label="@string/app_name" android:theme="@style/BlueLabel"><br /></pre><br />to set the theme of an activity programmatically call this line in the <b>onCreate</b> method<br /><pre class="brush:java">this.setTheme(R.style.BlueLabel);<br /></pre></div>

In web design we have the concept of Styles and Themes. Styles like Cascading Style Sheets (CSS) define the values of the web controls attri...

Android Error: Error generating final archive: Debug certificate expired on …

One day I opened eclipse to start a new android application, after creating the project and trying to run it I received the following error:<br /><br /><span style="color: red;">[2010-08-27 15:32:04 – (Project Name)] Error generating final archive: Debug certificate expired on 7/30/10 10:42 PM!</span><br /><br />After searching I found this link which suggests the solution: <a href="http://www.androidian.de/?p=940">http://www.androidian.de/?p=940</a>.<br /><br />The problem comes from the fact that Android required the applications to be signed even in the debug mode. So it uses a keystore file called <strong>debug.keystore</strong> to providde keys for signing applications in debug mode. This key store file has a validity period by default 365 days from its creation date.<br /><br /><span style="font-size: large;"><strong>The First Solution:</strong></span><br /><br /><br />Navigate to the .android folder in your home directory “<span style="font-family: "Courier New", Courier, monospace;">~/.android</span>” (Linux,Mac OS) or <span style="font-family: "Courier New", Courier, monospace;">c:\Documents and Settings\[User Name]\.android</span> in windows XP or <span style="font-family: "Courier New", Courier, monospace;">C:\Users\.android</span> in windows Vista or Windows 7, and delete debug.keystore file. Then go to eclipse clean the project, this will create a new debug.keystore file with default validity period 365 days.<br /><br /><span style="font-size: large;"><strong>The Second Solution:</strong></span><br /><br /><br />Create a new default.keystore file with custom validity period (say 1000 days).<br /><div></div><div></div><ol><li>Navigate to the .android folder.</li><li>Delete the old <strong>default.keystore</strong> file.</li><li>We will use <strong>JDK Keytool.exe</strong> to generate the new key file. It is found in <span style="font-family: "Courier New", Courier, monospace;">C:\Program Files\Java\jre6\bin</span> in windows or inside the <span style="font-family: "Courier New", Courier, monospace;">Java\jre6\bin</span> folder in Mac OS or Linux.</li><li>Open the terminal app in Mac OS or Linux or the command prompt and navigate to keytool.exe directory.</li><li>Run the following command:<br /><span style="font-family: "Courier New", Courier, monospace;">keytool -genkey -keypass android -keystore debug.keystore -alias androiddebugkey -storepass android -validity 1000 -dname “CN=Android Debug,O=Android,C=US”</span></li><li>This will generate a new default.keystore file with validity period 1000 days.</li><li>Copy the generated file to the .android folder, go to eclipse and clean projects and it should work.</li></ol>The above command has the following options:<br /><ul><li><strong>genkey:</strong> generates a key pair.</li><li><strong>keystore <Key Store Name>:</strong> the name of the key store file.</li><li><strong>alias <alias name>:</strong> an alias for the key store. If the alias name is more than 8 characters the first 8 only are used.</li><li><strong>storepass <password>:</strong> the password for the key.</li><li><strong>validity <Validty Period>:</strong> the validity period for the key in days.</li><li><strong>dname <name>:</strong> A Distinguished Name that describes who created the key. The value is used as the issuer and subject fields in the self-signed certificate.</li></ul><div></div>

One day I opened eclipse to start a new android application, after creating the project and trying to run it I received the following error:...

iPhone-Like Tab bar in Android

In a previous post we saw how to use the TabHost to create tabs in Android applications. Also we noticed that the Tabs in Android appear at the top of the activity.<br />but what if we want to give the tabs the look of the <b>iPhone Tab Bar</b> ?<br /><br />this is possible by wrapping the <b>TabWidget</b> and the <b>FrameLayout</b> in a <b>RelativeLayout</b> container and adding <b>android:layout_alignParentBottom="true"</b> attribute to the <b>TabWidget</b> just like this:<br /><pre class="brush:xml"><?xml version="1.0" encoding="utf-8"?><br /><br /><br /> <TabHost android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@android:id/tabhost"<br /> xmlns:android="http://schemas.android.com/apk/res/android"<br /> ><br /> <RelativeLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> ><br /> <TabWidget<br /> android:layout_width="fill_parent"<br /> android:layout_height="wrap_content"<br /> android:id="@android:id/tabs"<br /> android:layout_alignParentBottom="true"<br /> /><br /> <FrameLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@android:id/tabcontent"<br /> ><br /> <br /> </FrameLayout><br /> </RelativeLayout><br /> </TabHost><br /><br /><br /><br /></pre><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" bx="true" height="320" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs6.jpg" width="224" /></a></div>

In a previous post we saw how to use the TabHost to create tabs in Android applications. Also we noticed that the Tabs in Android appear at ...

Tabbed Applications in Android

Some times we want to wrap multiple views in a single window and navigate throught them with a Tab Container. this can be done in Android using <strong>TabHost</strong> control<br /><br />There are two ways to use a TabHost application in Android:<br /><ol><li>Using the TabHost to navigate through multiple views within the same activity.</li><li>Using the TabHost to navigate through Actual multiple Activities using intents.</li></ol>we will explain both ways through this tutorial<br /><br /><span style="font-size: large;">Anatomy of Tabbed Application</span><br />An activity with a TabHost may look like this:<br /><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" bx="true" height="320" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs1.jpg" width="258" /></a></div><br />The Activity consists of:<br /><ol><li>A TabHost: the root element of the layout.</li><li>The TabHost wraps a TabWidget which represents the tab bar.</li><li>The TabHost wraps a FrameLayout which wraps the contents of each tab.</li></ol>There are some rules that we must stick to when using a Tabbed activity:<br /><ol><li>If the activity is of type <strong>TabActivity</strong> [optional] then the TabHost must have the id <span style="color: blue;">@android:id/tabhost</span><span style="color: black;">.</span></li><li>The <strong>TabWidget</strong> must have the id <span style="color: blue;">@android:id/tabs</span>.</li><li>The <strong>FrameLayout</strong> must have the id <span style="color: blue;">@android:id/tabcontent</span>.</li></ol>no let's see an exaple to an activity with multiple tabs:<br />this is the layout<br /><pre class="brush:xml"><?xml version="1.0" encoding="utf-8"?><br /><br /><br /> <TabHost android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@+id/tabHost"<br /> xmlns:android="http://schemas.android.com/apk/res/android"<br /> ><br /> <TabWidget<br /> android:layout_width="fill_parent"<br /> android:layout_height="wrap_content"<br /> android:id="@android:id/tabs"<br /> /><br /> <FrameLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@android:id/tabcontent"<br /> ><br /> <LinearLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="wrap_content"<br /> android:id="@+id/tab1"<br /> android:orientation="vertical"<br /> android:paddingTop="60px"<br /> ><br /> <TextView <br /> android:layout_width="fill_parent" <br /> android:layout_height="100px" <br /> android:text="This is tab1"<br /> android:id="@+id/txt1"<br /> /><br /> <br /> <br /> </LinearLayout><br /> <br /> <LinearLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@+id/tab2"<br /> android:orientation="vertical"<br /> android:paddingTop="60px"<br /> ><br /> <TextView <br /> android:layout_width="fill_parent" <br /> android:layout_height="100px" <br /> android:text="This is tab 2"<br /> android:id="@+id/txt2"<br /> /><br /> <br /> </LinearLayout><br /> <br /> <LinearLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@+id/tab3"<br /> android:orientation="vertical"<br /> android:paddingTop="60px"<br /> ><br /> <TextView <br /> android:layout_width="fill_parent" <br /> android:layout_height="100px" <br /> android:text="This is tab 3"<br /> android:id="@+id/txt3"<br /> /><br /> <br /> </LinearLayout><br /> </FrameLayout><br /> <br /> </TabHost><br /></pre><br />then in the code of our activity<br /><pre class="brush:java">public void onCreate(Bundle savedInstanceState) {<br /> super.onCreate(savedInstanceState);<br /> setContentView(R.layout.main);<br /> TabHost tabHost=(TabHost)findViewById(R.id.tabHost);<br /> tabHost.setup();<br /> <br /> TabSpec spec1=tabHost.newTabSpec("Tab 1");<br /> spec1.setContent(R.id.tab1);<br /> spec1.setIndicator("Tab 1");<br /> <br /> TabSpec spec2=tabHost.newTabSpec("Tab 2");<br /> spec2.setIndicator("Tab 2");<br /> spec2.setContent(R.id.tab2);<br /> <br /> TabSpec spec3=tabHost.newTabSpec("Tab 3");<br /> spec3.setIndicator("Tab 3");<br /> spec3.setContent(R.id.tab3);<br /> <br /> tabHost.addTab(spec1);<br /> tabHost.addTab(spec2);<br /> tabHost.addTab(spec3);<br /> <br /> }<br /></pre><br />is going to look like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" bx="true" height="320" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs2.jpg" width="225" /></a></div><br /><ol><li>We create tabs using <strong>TabSpecs</strong> class.</li><li>We set the title of each tab using <strong>TabSpecs.setIndicator() </strong>method.</li><li>We set the content of each tab using <strong>TabSpecs.setContent() </strong>method.</li><li>if you use <strong>TabActivity</strong> to as a base class to your activity, you do not need to call <strong>TabHost.Setup()</strong> method.</li></ol>We can add an icon to the title of the tab like this:<br /><pre class="brush:java">TabSpec spec1=tabHost.newTabSpec("Tab 1");<br /> spec1.setContent(R.id.tab1);<br /> spec1.setIndicator("Tab 1",getResources().getDrawable(R.drawable.flash));<br /> <br /> <br /> TabSpec spec2=tabHost.newTabSpec("Tab 2");<br /> spec2.setIndicator("Tab 2",getResources().getDrawable(R.drawable.sun));<br /> spec2.setContent(R.id.tab2);<br /> <br /> TabSpec spec3=tabHost.newTabSpec("Tab 3");<br /> spec3.setIndicator("Tab 3",getResources().getDrawable(R.drawable.chart));<br /> spec3.setContent(R.id.tab3);<br /></pre><br />it will look like this:<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" bx="true" height="320" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs3.jpg" width="227" /></a></div><br />we can also specify the indicator to be a view:<br /><pre class="brush:java">TabSpec spec1=tabHost.newTabSpec("Tab 1");<br /> spec1.setContent(R.id.tab1);<br /> TextView txt=new TextView(this);<br /> txt.setText("Tab 1");<br /> txt.setBackgroundColor(Color.RED);<br /> spec1.setIndicator(txt);<br /></pre><br /><br /><br /><span style="font-size: large;">Setting the content of tabs:</span><br /><br />we saw how to set the contents of tabs by specifying multiple layout resources to be displayed within the same activity.<br /><br />what If we have multiple Activities in our application and we want to navigate between them using tabs ?<br />in this case we will have one activity as the root activity of the application. this activity will have the <b>TabHost</b> and will navigate to other activities using <b>Intents</b>.<br /><b>Note:</b> the root activity must inherit from <b>TabActivity</b>.<br /><br />the root activity will have layout file like this:<br /><pre class="brush:xml"><?xml version="1.0" encoding="utf-8"?><br /> <TabHost android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@android:id/tabhost"<br /> xmlns:android="http://schemas.android.com/apk/res/android"<br /> ><br /> <TabWidget<br /> android:layout_width="fill_parent"<br /> android:layout_height="wrap_content"<br /> android:id="@android:id/tabs"<br /> /><br /> <FrameLayout<br /> android:layout_width="fill_parent"<br /> android:layout_height="fill_parent"<br /> android:id="@android:id/tabcontent"<br /> ><br /> </FrameLayout><br /> </TabHost><br /></pre><br />the other activities will have a simple layout consisting of a <b>TextView</b>.<br /><br />now to the code of the roor activity<br /><pre class="brush:java">public class TabDemo extends TabActivity {<br /> /** Called when the activity is first created. */<br /> @Override<br /> public void onCreate(Bundle savedInstanceState) {<br /> super.onCreate(savedInstanceState);<br /> setContentView(R.layout.main);<br /><br /> TabHost tabHost=getTabHost();<br /> // no need to call TabHost.Setup() <br /> <br /> //First Tab<br /> TabSpec spec1=tabHost.newTabSpec("Tab 1");<br /> spec1.setIndicator("Tab 1",getResources().getDrawable(R.drawable.sun));<br /> Intent in1=new Intent(this, Act1.class);<br /> spec1.setContent(in1);<br /> <br /> TabSpec spec2=tabHost.newTabSpec("Tab 2");<br /> spec2.setIndicator("Tab 2",getResources().getDrawable(R.drawable.chart));<br /> Intent in2=new Intent(this,Act2.class);<br /> spec2.setContent(in2);<br /><br /> tabHost.addTab(spec2);<br /> tabHost.addTab(spec3);<br /> }<br />}<br /></pre><br />and the activity will look like this<br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" bx="true" height="320" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs4.jpg" width="224" /></a></div><br /><br /><span style="font-size: large;">Adding tabs at run-time:</span><br /><br />we can add tabs to <b>TabHost</b> at run-time using <b>TabSpec.setContent(TabContentFactory)</b> method.<br /><br />the <b>TabContentFactory</b> is an interface that requires the implementation of a callback method <b>createTabContent(String tag)</b> which returns the view to be added to the content of the tab.<br /><br />so in the last example if we changed code that adds the content of the second tab to this:<br /><pre class="brush:java">TabSpec spec1=tabHost.newTabSpec("Tab 1");<br /> spec1.setIndicator("Tab 1",getResources().getDrawable(R.drawable.sun));<br /><br /> spec1.setContent(new TabContentFactory() {<br /> <br /> @Override<br /> public View createTabContent(String tag) {<br /> // TODO Auto-generated method stub<br /> <br /> return (new AnalogClock(TabDemo.this));<br /> }<br /> });<br /></pre><br />the activity will look like this<br /><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" bx="true" height="320" src="http://dl.dropbox.com/u/2624328/Android%20Pro/2010/August/Tabs/Tabs5.jpg" width="225" /></a></div>

Some times we want to wrap multiple views in a single window and navigate throught them with a Tab Container. this can be done in Android us...