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Showing posts from January, 2013

PreferenceActivity , PreferenceFragment and headers (Part 2)

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In previous post we described how to use Preference Activity and Preference Fragment.

Android 3.0 (API Level 11) introduced Preference Headers through which we can show the user the list of headers, and upon clicking on a header, show the fragment.
A great benefit to using this design is that PreferenceActivity automatically presents the two-pane layout when running on large screens.

This behavior is particularly useful if you have more than 10 preferences, otherwise I suggest the direction of displaying headers all of the time.

Scenario 3: Preference Headers
Step 1: Define the preferences_headers_scenario3.xml
This file lists each settings group and declares which fragment contains the corresponding list of settings.The file is placed in the res\xml folder.
With the android:fragment attribute, each header declares an instance of PreferenceFragment that should open when the user selects the header.
Step 2: Create the Preference Activity
To display the preference headers, you must impl…

PreferenceActivity , PreferenceFragment and headers (Part 1)

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In this tutorial we will build a preference screen in different ways.

Android provides a powerful xml driven framework to manage user preferences, that allows us to easily create preference screens such as those in Android itself and it automatically generates UI for that. 
All we need to do is to simply use it in our app.

See these pages for more information on PreferenceActivity.and PreferenceFragment.
We will evaluate 4 scenarios:
Scenario 1: PreferenceActivityScenario 2: PreferenceFragmentScenario 3: Preference HeadersScenario 4: PreferenceFragment and Headers with older versions
Scenario 1: PreferenceActivity

In this scenario we will use a very simple but common example.
Define the preferences_scenario1.xml
The Preferences Activity screen is defined in the preferences_scenario1.xml file as shown below. This file is placed in the res\xml folderStep 2: Create the Preference Activity
Prior to Android 3.0, the Preference Activity was used to host Preference Screens directly. For applicati…

Android Logging

This post describes how to create log statements in Android applications.

Android uses the android.util.Log class for logging. This class supports various levels (VERBOSE, DEBUG, INFO, WARN, ERROR) and contains numerous methods to print debugging information to the logcat utility.Logcat is visible in the debug perspective in Eclipse or by running adb logcat on the command line. You can read more about it here.
Log.w("MyTag", "Mymessage"); This code will output a warning with the tag MyTag and the message "Mymessage".
The first parameter of these method is the category and the second is the message.

Usually you use this code:
public static final String TAG = "it.gmariotti.android.apps.Myapp"; log.w(TAG,"MyMessage"); It is very important to turn down logging when you deploy your app to the market.
Google advises that a deployed application should not contain logging code.

We can find a very good example in Google I/O 2012 app.
public stat…

How use Prettify in new Blogger Dynamic Views

I've started to use Blogger. First thing I've wanted to use in my posts a SyntaxHighlighter.
I've chosen google-code-prettify.
It is easy to setup, Google uses it, and it works very well.

You can find instructions here.

Go to the blogger dashboard, then click Template link present on the left-hand-side listclick on Edit HTML button.Edit HTML dialog box will appear.Put the following tags in <head> tag section of HTML template.<linkhref="http://google-code-prettify.googlecode.com/svn/trunk/src/prettify.css"type="text/css"rel="stylesheet"/><scripttype="text/javascript"src="http://google-code-prettify.googlecode.com/svn/trunk/src/prettify.js"></script> Edit the <body> tag and it should look like as shown below. <bodyonload="prettyPrint()" ... > Once you are done, just save the template.
Note that is not working with Dynamic Views, because posts are loaded asynchronously.…

A new blog

Hello, this is my new blog about Android development.
Topics center around problems that I stumbled upon and solutions that I found helpful.