Sometimes it’s the little problems in life that can be so challenging, but when solved are the most rewarding. As such is my experience with changing the colors on the Android TabWidget object. I spent several days and nights searching for documentation, reading the responses to questions other developers have posted, trying different things to get this simple problem solved and finally the “AHA!” moment came last night during my sleep. I woke up this Sunday morning at 6 AM with the solution on my mind. So for about an hour and half before going to church, I solved one of the greatest programming challenges I’ve faced in many years—how to change the tab colors on the Android TabWidget and keep the dividers in their proper place.
Some of you might have this figured out already, but from the great number of unanswered questions on the net, I’ll assume most haven’t. There’s so little documentation for some of these more esoteric Android features. The books I’ve read are good to get someone started with Android, some are even helpful. But I haven’t found one yet that teaches the common tasks programmers are likely to do when they’re coding.
The answer to my question was right in front of me the entire time. I found the solution in the Android SDK. I’m coding my app for Froyo or higher. The minimum SDK version for this solutions is 8. I have not tested to see if it works on the previous SDK versions. You’re on your own for that.
To illustrate what I’ve done, take a look at the two emulator screen captures below.
 Fig 1. Standard Grey Tabs |
 Fig 2. Modified Blue Tabs |
The goal is to allow users to choose between a dark (Fig. 1) and light (Fig. 2) color scheme. The choice is made in a CheckBoxPreference object through the Preferences framework.
As soon as a user selects or deselects the Light Colors checkbox, the tab screen changes color immediately upon returning to it from Preferences.
It’s really quite easy to control the tab colors. What’s not so easy is to control the orange bars that display to the left and right of a tab when it is pressed. Actually, they can be changed but it’s not recommended to do so because you have to access them through the internal Android API (com.android.internal). Doing anything through the internal API is risky. You’ll never know how the internals will change over time which can cause your application to break and security risks are inherent.
To modify the tab colors, first copy tab_indicator_v4.xml or tab_indicator.xml from android-sdk-windowsplatformsandroid-8dataresdrawable to the resdrawable folder in your project. If you don’t have a resdrawable folder, create it and then copy the file from the SDK. The content of the file is:
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 |
<!-- Copyright (C) 2008 The Android Open Source Project Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at <a href="http://www.apache.org/licenses/LICENSE-2.0">http://www.apache.org/licenses/LICENSE-2.0</a> Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <selector xmlns:android="<a href="http://schemas.android.com/apk/res/android">http://schemas.android.com/apk/res/android</a>"> <!-- Non focused states --> <item android:state_focused="false" android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/tab_unselected_v4" /> <item android:state_focused="false" android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/tab_selected_v4" /> <!-- Focused states --> <item android:state_focused="true" android:state_selected="false" android:state_pressed="false" android:drawable="@drawable/tab_focus" /> <item android:state_focused="true" android:state_selected="true" android:state_pressed="false" android:drawable="@drawable/tab_focus" /> <!-- Pressed --> <item android:state_pressed="true" android:drawable="@drawable/tab_press" /> </selector> |
The @drawables in this file control the appearance of the tabs in their various states, i.e. pressed, focused, selected, etc. These drawables are .png graphics located in your project’s drawables-hdpi directory. You can get the graphics referenced in this file from the drawables-hdpi directory for the platform of your choice in the Android SDK. You assign this file as the background resource for your tabwidget.
I created two versions of this .XML file. The first is for the dark theme, the other for the light theme. The only difference is the name of the @drawables graphics I’m using in each. To make the blue selected and unselected .png graphics I made copies of tab_selected_v4.9.png and tab_unselected_v4.9.png from the SDK. Then I used the color replacement tool in Photoshop to create the new images.
The following Java example is a custom method I wrote for my app’s tab activity to set the background resource to either file based on the user preference IsLightColors.
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 |
protected void setTabColors() { /** * Before we do anything, determine saved value of IsLightColors */ MyApp app = (MyApp) this.getApplication(); IsLightColors = app.RetrieveBoolean(getString(R.string.LightColorsKey)); // set the color scheme and resource based on IsLightColors user prefs int tab_indicator = IsLightColors ? R.drawable.tab_indicator_v4_light : R.drawable.tab_indicator_v4; int layoutColor = IsLightColors ? Color.WHITE : Color.BLACK; View myLayout = findViewById(R.id.main_layout); myLayout.setBackgroundColor(layoutColor); // set the background resource for each tab for (int i = 0; i < tabHost.getTabWidget().getChildCount(); i++) { tabHost.getTabWidget().getChildAt(i).setBackgroundResource(tab_indicator); } } |
This code snippet references app.RetrieveBoolean. You won’t find this method in Android. This is another custom method I wrote for an app-level extension library. Using this method, we obtain the value of IsLightColors from the Preferences framework and the rest is apple pie!
I certainly hope this has shed some light on the tab color issue and helped you in your quest to customize your tabs.
Attribution
Android is a trademark of Google Inc.
Great! this solution is really works well. This is really a simplest way to customize the tab colors..
Thanks a lot.
-Rajesh
I really want to save this particular posting, “A Simple Yet Advanced Lesson in Android Programming—Changing TabWidget
Tab Colors” on my own webpage. Will you mind if Ido it? Many
thanks ,Carrie
Thanks for a great tutorial,
it work for me, but i have one problem, background image cannot repeat.
I test on android 2.3, whats problem with my code ?. this is my code:
package com.linear;
import android.os.Bundle;
import android.app.TabActivity;
import android.content.Intent;
import android.widget.TabHost;
import android.widget.TabHost.TabSpec;
import android.widget.TabHost.OnTabChangeListener;
public class LinearLayoutSederhana extends TabActivity implements OnTabChangeListener{
TabHost tabHost;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tabHost = getTabHost();
tabHost.setOnTabChangedListener(this);
/*
* Define tab untuk game
* Tambahkan dulu GamesActivity di Android Manifest
* */
TabSpec gameSpec = tabHost.newTabSpec(“Game”);
gameSpec.setIndicator(“Game”,getResources().getDrawable(R.drawable.honeycomb_games));
Intent gameIntent = new Intent(this,GamesActivity.class);
gameSpec.setContent(gameIntent);
tabHost.addTab(gameSpec);
/*
* Define tab untuk Music
* Tambahkan dulu MusicActivity di Android Manifest
* */
TabSpec musicSpec = tabHost.newTabSpec(“Music”);
musicSpec.setIndicator(“Music”,getResources().getDrawable(R.drawable.honeycomb_music));
Intent musicIntent = new Intent(this,MusicActivity.class);
musicSpec.setContent(musicIntent);
tabHost.addTab(musicSpec);
/*
* Define tab untuk Video
* Tambahkan dulu VideoActivity di Android Manifest
* */
TabSpec videoSpec = tabHost.newTabSpec(“Video”);
videoSpec.setIndicator(“Video”,getResources().getDrawable(R.drawable.honeycomb_video));
Intent videoIntent = new Intent(this,VideoActivity.class);
videoSpec.setContent(videoIntent);
tabHost.addTab(videoSpec);
for(int i=0;i<tabHost.getTabWidget().getChildCount();i++)
{
//tabHost.getTabWidget().getChildAt(i).setBackgroundColor(Color.parseColor("#8A4117"));
tabHost.getTabWidget().getChildAt(i).setBackgroundResource(R.drawable.tab_indicator_v4);
}
tabHost.getTabWidget().setCurrentTab(0);
//tabHost.getTabWidget().getChildAt(0).setBackgroundColor(Color.parseColor("#C35817"));
tabHost.getTabWidget().getChildAt(0).setBackgroundResource(R.drawable.tab_indicator_v4);
}
public void onTabChanged(String tabId) {
// TODO Auto-generated method stub
for(int i=0;i<tabHost.getTabWidget().getChildCount();i++)
{
//tabHost.getTabWidget().getChildAt(i).setBackgroundColor(Color.parseColor("#8A4117"));
tabHost.getTabWidget().getChildAt(i).setBackgroundResource(R.drawable.tab_indicator_v4);
}
//tabHost.getTabWidget().getChildAt(tabHost.getCurrentTab()).setBackgroundColor(Color.parseColor("#C35817"));
tabHost.getTabWidget().getChildAt(tabHost.getCurrentTab()).setBackgroundResource(R.drawable.tab_indicator_v4);
}
}
And this is my tab_indicator_v4.xml :
Thanks for this tutorial it works good.
But I have a little problem.
I have make a copies of tab_selected.9.png and tab_unselected.9.png from the SDK into my drawable. Then I used the color replacement tool in gimp to create the new images.
My problem is by android:drawable”@drawable/tab_press” and android:drawable=”@drawable/tab_focus” Eclipse show the message “Error: No resource found that matches the given name (at ‘drawable’ with value ‘@drawable/tab_focus’).”
I would use the default color for press an focus state is this possible?
I am an android developer. I read your article through googleing, and thanks for your blog. It was very useful for me. Your article gave me clue to improve tab widget in my application.