Develop Reference

Android: Is it possible to create both Bottom and Top tabs on the screen?

I would like to know if its possible to have different tabs on the top and bottom that lead to different activities when clicked. Googled it but didnt find anything about it.
Thanks

The good thing with Android is that almost everything you want to do should be possible. If we were to alter your XML we would change it to something like:
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TabWidget
android:id="#android:id/tabs_top"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0" />
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="0dip"
android:layout_weight="1" />
<TabWidget
android:id="#android:id/tabs_bottom"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0" />
</LinearLayout>
</TabHost>
Notice that I've changed the ID's of the TabWidgets.
This is only half of the problem. The other half is how the source code for the core class TabHost should altered to accommodate this change.
You can review the source of the original TabHost here. Looking at the source it's pretty obvious the code has a single mTabWidget and this is initialized using the very specific ID = tabs (com.android.internal.R.id.tabs). We've changed the ID's so we should be mindful of this.
So, how can we alter the original source? One approach is to make our own class and extend the core TabHost. This will not be easy because half of the functions and members inside the original TabHost are private (why aren't they protected?!?). Anyways, since you have the source code and it's pretty simple, it's possible to do it.
Let's say your new extended class is MyTabHost (potentially place it in the same package as the original TabHost just so you can access variables/functions which have no private or public), then you can replace in the XML the word TabHost with MyTabHost or com.yourpackage.MyTabHost actually) and then your class will be used in the XML instead of the original.
From looking at the source code, it's obvious that this feature isn't supported by default. But - I think that if you really want to make it happen, you can see a way.

TabHost on Android 4.2 - Icons and Colours Not Showing on Tabs

We're very new to Android development, so apologies if this is obvious.
We're implementing an activity using a tabbed view. The problem we are having is that the icons and proper colours on the tabs themselves do not show up properly on Jelly Bean (Android 4.2). They DO, however, display properly on earlier API levels, such as Gingerbread.
Please note: We did originally create the view using the deprecated TabActivity class. However, as far as I can tell, the "newer" way of doing this shouldn't be that different from the old? Please correct me if I am wrong.
This is the xml containing the tab host layout:
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/Black">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp">
<include layout="#layout/logo_bar"/>
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0"/>
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1" >
</FrameLayout>
</LinearLayout>
</TabHost>
Here is the relevant (I hope) activity code:
public class MainTabActivity extends FragmentActivity implements TabHost.TabContentFactory
private TabHost tabHost;
// other instance variables ...
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
tabHost = (TabHost)findViewById(android.R.id.tabhost);
tabHost.setup();
TabSpec loginTabSpec = tabHost.newTabSpec(GlobalConstants.LOGIN_ACTIVITY);
loginTabSpec.setIndicator("Settings", getResources().getDrawable(R.drawable.ic_action_settings_gear));
loginTabSpec.setContent(this);
TabSpec mainTabSpec = tabHost.newTabSpec(GlobalConstants.MAIN_ACTIVITY);
mainTabSpec.setIndicator("Lone Worker", getResources().getDrawable(R.drawable.ic_action_settings_phone));
mainTabSpec.setContent(this);
tabHost.addTab(mainTabSpec);
tabHost.addTab(loginTabSpec);
}
This is what the tab itself looks like on Jelly Bean (bad version):
And finally, this is what it should look like (on gingerbread... good version):
So to re-iterate: The background colour of the tab is black (when it is normally that nice blue colour), and though it is difficult to tell from the bad screen shot, the icons for either tab are missing show up on jelly bean. I hope the problem is outlined enough here. Please let me know if I've left anything out. Thank you in advance!

For whatever reason in later versions of Android (>= ICS) tabs can only have a text label or an icon if you are using
setIndicator(CharSequence label, Drawable icon)
I suspect the reason you don't see any text is because the default text color for tabs in ICS is black, so its there just not visible on your black background.
A solution is to create your own view and use
setIndicator(View view)
More details here: Icon in Tab is not showing up
and here http://ondrejcermak.info/en/programovani/custom-tabs-in-android-tutorial/

Tab-Control inside normal Activity, is it possible?

I'm running into trouble when try to put an tabhost layout inside an normal layout.
The structure of my layout is:
<LinearLayout >
<LinearLayout>
....
</LinearLayout>
<TabHost>
.....
</TabHost>
</LinearLayout>
I try to draw this picture to help it easier to image about what I'm saying:
Can you give me a hint for this problem ? I will do the rest, no need a full solution, just a hint, please :)
Thanks .

It's been a little while since I dealt with Android, but if I recall TabHost is essentially a container that stores both the tabs and the viewport that the tabs switch between. TabHost extends from FrameLayout so you can use it as the root element in a layout. What I think you actually want is this:
<TabHost>
<LinearLayout android:layout_orientation="vertical">
<TextView /> // your title
<View /> // content below your title but above your tabs
<TabWidget /> // your tabs
<FrameLayout /> // content controlled by your tabs
</LinearLayout>
</TabHost>

How to add controls to a Tab Layout in Android?

I am following this tutorial https://developer.android.com/guide/tutorials/views/hello-tabwidget.html and have completed it. Now I would actually like to add you know some controls to these tabs like textboxes(text edit).
How do I do this? I go to my mail.xml using eclipse as my ide and go to layout view and I now get a NullPointerException so I can't even drag stuff onto the layout anymore.
Edit
This is what I have
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:id="#+id/textview1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="this is a tab" />
<EditText android:text="" android:id="#+id/EditText01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:password="true"></EditText>
</LinearLayout>
<TextView
android:id="#+id/textview2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="this is another tab" />
<TextView
android:id="#+id/textview3"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="this is a third tab" />
</FrameLayout>
</LinearLayout>
</TabHost>

Tabs are a bit funny to get working initially since there's a lot of code overhead, but once you've worked your way through that they aren't too bad. To get tabs to work, let's start by improving your XML file and then we can make sure your code to actually load them is correct.
First off, your XML file. Instead of including everything directly in your main.xml, you should use the include feature. As the name would suggest, this lets you work on a separate xml file and then include it in your main with one line. This makes the main.xml file much easier to read. So we'd modify your file above to make it look like this:
//No need to change anything above this
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<include layout="#layout/tab1"/>
<include layout="#layout/tab2"/>
//and however many other tabs you want to include
</FrameLayout>
You then need to create tab1.xml, tab2.xml and so forth. These are normal xml files in that they start with a ViewGroup (i.e. LinearLayout, RelativeLayout) which contains any number of other widgets. These widgets can be things like EditTexts, buttons, custom views, whatever you want. The only rule is that the parent ViewGroup (the one at the top) must have a unique ID in it, in the manner of android:id="#+id/someUniqueName". You will use that to refer to that specific layout/tab in your code. So for example, this would be:
tab1.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/tab1Layout"
android:orientation="vertical">
<TextView ... />
<EditText ... />
</LinearLayout>
With that done, we can look at your code. I assume you've probably already got this, but just in case here's what you want:
public class YourProject extends TabActivity {
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Resources res = getResources();
TabHost tabHost = getTabHost();
tabHost.addTab(tabHost.newTabSpec("tab1").setIndicator("Tab1 title",
res.getDrawable(R.drawable.logo1)).setContent(R.id.tab1Layout));
(...)
//You can also fill tabs with a separate activity like so:
Intent intent = new Intent(this, YourClass.class);
tabHost.addTab(tabHost.newTabSpec("tab2").setIndicator("Another title",
res.getDrawable(R.drawable.logo2)).setContent(intent));
tabHost.setCurrentTab(0);
}
}
As shown above you can set the content of one of the tabs to be a separate activity. In that case, the activity is defined just as any other one with its own Class, layout, etc. Usually you shouldn't do this and instead just use a different View (with setContent(R.id.tabXLayout), but sometimes it's needed. For example if you want one of your tabs to have a list, then you need to start an activity in there that extends ListView, and include all the boilerplate code for ListViews.
I hope that helps!

The layout view in Eclipse can be a bit flaky, particularly with complex layouts. A bit of trial and error might find the View node it is choking on.
As regards developing the tab-based layout further, you have two options, the 'quick' way or the 'right' way. First is to adapt the existing layout xml by replacing one of the TextViews with a LinearLayout (or some other layout) which contains the content you want.
http://google.com/codesearch/p?hl=en#HQNWZ1u2Pig/trunk/HelloLayoutAndroid/res/layout/tab_widget.xml
However Tabs are generally used where there is complex content. For scalability it may be better to locate the TabHost in the layout, call newTabSpec() and then use setContent() to supply an Intent that identifies an internal Activity, which supplies its own Layout.

the include often makes problems while parsing XML, I tried it and got :cannot resolve #layout/mylayout..
my code was correct 100%, but it's common problem spicialy if you need Id for the layout and other attributes.
samply: I solve it by the disign mode, when you drop tabhost to your layout, place it wherever you want, it creates 3 Linear layouts (tab1,tab2,tab3)... on XML editor, in each tab (leanearlayout) insert your markup of the control you need to use as content of the tab.
and in java file do the next:
TabHost tabHost = (TabHost)findViewById(R.id.tabHost);
tabHost.setup();
TabHost.TabSpec tab1 = tabHost.newTabSpec("smil1");
TabHost.TabSpec tab2 = tabHost.newTabSpec("smil2");
TabHost.TabSpec tab3 = tabHost.newTabSpec("smil3");
tab1.setIndicator("#1");//the name will apear on the first tab
tab1.setContent(R.id.smiles1); // the Id of the control you put in the first LeanerLayout
tab2.setIndicator("#2"); // the same as abouv but for the second tab
tab2.setContent(R.id.smiles2);
tab3.setIndicator("#3"); // the thierd tab
tab3.setContent(R.id.smiles3);
// add the tabs
tabHost.addTab(tab1);
tabHost.addTab(tab2);
tabHost.addTab(tab3);
this is the way solving your problem if include makes problem in parsing your XML.

The NullPointerException in the layout editor is a known bug in the Android Development Tools.

Android: Tabs at the BOTTOM

I've seen some chatter about this, but nothing definite.
Is there a way to put the tabs in a TabWidget to the bottom of the screen?
If so, how?
I've tried the following, but didn't work:
a) setting the tabwidget below the framelayout
b) setting the tabwidget's gravity to "bottom"
Thanks!
llappall

Here's the simplest, most robust, and scalable solution to get tabs on the bottom of the screen.
In your vertical LinearLayout, put the FrameLayout above the TabWidget
Set layout_height to wrap_content on both FrameLayout and TabWidget
Set FrameLayout's android:layout_weight="1"
Set TabWidget's android:layout_weight="0" (0 is default, but for emphasis, readability, etc)
Set TabWidget's android:layout_marginBottom="-4dp" (to remove the bottom divider)
Full code:
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp">
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:padding="5dp"
android:layout_weight="1"/>
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0"
android:layout_marginBottom="-4dp"/>
</LinearLayout>
</TabHost>

Try it ;)
Just watch the content of the FrameLayout(#id/tabcontent), because I don't know how it will handle in case of scrolling... In my case it works because I used ListView as the content of my tabs. :)
Hope it helps.
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<FrameLayout android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:layout_above="#android:id/tabs" />
<TabWidget android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" />
</RelativeLayout>
</TabHost>

There is a way to remove the line.
1) Follow this tutorial:
android-tabs-with-fragments
2) Then apply the RelativeLayout change that Leaudro suggested above (apply the layout props to all FrameLayouts).
You can also add an ImageView to the tab.xml in item #1 and get a very iPhone like look to the tabs.
Here is a screenshot of what I'm working on right now. I still have some work to do, mainly make a selector for the icons and ensure equal horizontal distribution, but you get the idea.
In my case, I'm using fragments, but the same principals should apply to a standard tab view.

Not sure if it will work for all versions of Android (especially those with custom UI stuff), but I was able to remove the gray bar at the bottom by adding
android:layout_marginBottom="-3dp"
to the TabWidget XML...

For all those of you that try to remove the separating line of the tabWidget, here is an example project (and its respective tutorial), that work great for customizing the tabs and thus removing problems when tabs are at bottom.
Eclipse Project: android-custom-tabs ;
Original explanation: blog;
Hope this helped.

There are two ways to display tabs at the bottom of a tab activity.
Using relative layout
Using Layout_weight attribute
Please check the link for more details.

This may not be exactly what you're looking for (it's not an "easy" solution to send your Tabs to the bottom of the screen) but is nevertheless an interesting alternative solution I would like to flag to you :
ScrollableTabHost is designed to behave like TabHost, but with an additional scrollview to fit more items ...
maybe digging into this open-source project you'll find an answer to your question. If I see anything easier I'll come back to you.

I was having the same problem with android tabs when trying to place them on the bottom of the screen. My scenario was to not use a layout file and create the tabs in code, I was also looking to fire activities from each tab which seemed a bit too complex using other approaches so, here is the sample code to overcome the problem:
adding-tabs-in-android-and-placing-them

Yes, see: link, but he used xml layouts, not activities to create new tab, so put his xml code (set paddingTop for FrameLayout - 0px) and then write the code:
public class SomeActivity extends ActivityGroup {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TabHost tab_host = (TabHost) findViewById(R.id.edit_item_tab_host);
tab_host.setup(this.getLocalActivityManager());
TabSpec ts1 = tab_host.newTabSpec("TAB_DATE");
ts1.setIndicator("tab1");
ts1.setContent(new Intent(this, Registration.class));
tab_host.addTab(ts1);
TabSpec ts2 = tab_host.newTabSpec("TAB_GEO");
ts2.setIndicator("tab2");
ts2.setContent(new Intent(this, Login.class));
tab_host.addTab(ts2);
TabSpec ts3 = tab_host.newTabSpec("TAB_TEXT");
ts3.setIndicator("tab3");
ts3.setContent(new Intent(this, Registration.class));
tab_host.addTab(ts3);
tab_host.setCurrentTab(0);
}
}

I recomend use this code for stable work, it optimized for nested fragments in tab (for example nested MapFragment) and tested on "do not keep activities": https://stackoverflow.com/a/23150258/2765497