android

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Android 3 : Employing Basic Widgets - Turn the Radio Up, It's Quite a View

As with other implementations of radio buttons in other toolkits, Android's radio buttons are two-state, like check boxes, but can be grouped such that only one radio button in the group can be checked at any time.

Android 3 : Employing Basic Widgets - Just Another Box to Check

In Android, there is a CheckBox widget to meet this need. It has TextView as an ancestor, so you can use TextView properties like android:textColor to format the widget.

Android 3 : Employing Basic Widgets - Fleeting Images, Fields of Green...or Other Colors

Android has two widgets to help you embed images in your activities: ImageView and ImageButton. As the names suggest, they are image-based analogues to TextView and Button, respectively.

Android 3 : Employing Basic Widgets - Assigning Labels

The simplest widget is the label, referred to in Android as a TextView. As in most GUI toolkits, labels are bits of text that can't be edited directly by users. Typically, labels are used to identify adjacent widgets .

Android Application Development : Signing and Publishing Your Application (part 2)

If you’re familiar with other mobile development environments (J2ME, Symbian, BREW, etc.), you’re probably an old hand at signing applications. But if you’re new to developing mobile applications, you may be asking yourself what all this signing stuff is for, anyway.

Android Application Development : Signing and Publishing Your Application (part 1)

You’ve probably been developing your application using the Android Emulator that is part of the Android Developers Kit. If you haven’t already done so, take the time to load your application on a real Android device (such as the T-Mobile G1 phone), and test the application again.

Android : Getting Fancy with Lists - Interactive Rows

Lists with pretty icons next to them are all fine and well. But, can we create ListView widgets whose rows contain interactive child widgets instead of just passive widgets like TextView and ImageView?

Android : Getting Fancy with Lists - Better. Stronger. Faster.

The getView() implementation shown in the FancyLists/DynamicEx project works, but it's inefficient. Every time the user scrolls, we have to create a bunch of new View objects to accommodate the newly shown rows. This is bad.

Android : Getting Fancy with Lists - Inflating Rows Ourselves

The preceding version of the DynamicDemo application works fine. However, sometimes ArrayAdapter cannot be used even to set up the basics of our row. For example, it is possible to have a ListView where the rows are materially different, such as category headers interspersed among regular rows.

Android : Getting Fancy with Lists - A Dynamic Presentation

The classic Android ListView is a plain list of text—solid but uninspiring. Basically, we hand the ListView a bunch of words in an array and tell Android to use a simple built-in layout for pouring those words into a list.

Android : Getting Fancy with Lists - Getting to First Base

Android : Using Selection Widgets - . Fields

The AutoCompleteTextView is sort of a hybrid between the EditText (field) and the Spinner. With autocompletion, as the user types, the text is treated as a prefix filter, comparing the entered text as a prefix against a list of candidates.

Android : Using Selection Widgets - Grid Your Lions (or Something Like That...)

GridView gives you a two-dimensional grid of items to choose from. You have moderate control over the number and size of the columns; the number of rows is dynamically determined based on the number of items the supplied adapter says are available for viewing.

Android : Using Selection Widgets - Spin Control

In Android, the Spinner is the equivalent of the drop-down selector you might find in other toolkits (e.g., JComboBox in Java/Swing). Pressing the center button on the D-pad pops up a selection dialog box from which the user can choose an item.

Android : Using Selection Widgets - Adapting to the Circumstances, Lists of Naughty and Nice

The classic list box widget in Android is known as ListView. Include one of these in your layout, invoke setAdapter() to supply your data and child views, and attach a listener via setOnItemSelectedListener() to find out when the selection has changed. With that, you have a fully functioning list box.

Android Application Development : The ApiDemos Application (part 2) - Adding Your Own Examples to ApiDemos

The ApiDemos application is a handy sandbox for your own testing, and adding a new menu entry and Activity to it is quite easy. But remember that whenever you upgrade your API, all of your changes will be lost. Don’t add code to the ApiDemo that you might want to save after an upgrade. It really is just a sandbox for quick tests.

Android Application Development : The ApiDemos Application (part 1) - Application Setup in the Manifest File, Finding the Source to an Interesting Example

The ApiDemos application has a lot of interesting examples that will help you learn how to program an Android application. However, it’s not entirely obvious how to find the source to any particular screen.

Debugging Android Applications : Eclipse Java Editor (part 5) - Traceview

Traceview is a utility that allow you just that kind of visibility. It consists of two parts, one that you enable before running your program and one that you work with after the run in order to diagnose your findings:

Debugging Android Applications : Eclipse Java Editor (part 4) - Android Debug Bridge, Dalvik Debug Monitor Service

Android comes with a specialized command-line debug utility called adb. It lets you control a device or emulator from your host, offering the kind of remote terminal or remote shell service that embedded programmers have come to expect when working with their target systems.

Debugging Android Applications : Eclipse Java Editor (part 3) - Logcat

Granted, the errors we debugged in the last section were pretty straightforward—no different from debugging in any other environment. But most applications are not as simple as DebugTest, and many problems are much harder to isolate and solve.

Debugging Android Applications : Eclipse Java Editor (part 2) - The Debugger

The Android SDK makes the use of the Eclipse debugger completely transparent, so let’s use it to see what’s going wrong with our program. We’ll put a breakpoint at the line we just entered, so the debugger will break there when we run the program.

Debugging Android Applications : Eclipse Java Editor (part 1) - Java Errors

The Android SDK takes full advantage of the features built into the Eclipse IDE, including those in the Eclipse text editor, which is customized for Java source code development.

Setting Up Your Android Development Environment : Hello, Android

Several components are needed to build an Android application. Fortunately, the Eclipse IDE with the Android plug-in automates a lot of the work needed to create and maintain these components.

Setting Up Your Android Development Environment : Setting Up Your Development Environment

Android applications, like most mobile phone applications, are developed in a host-target development environment. In other words, you develop your application on a host computer (where resources are abundant) and download it to a target mobile phone for testing and ultimate use.

Android Application Development : Initialization in MicroJobs.java (part 2)

The previous section was a rather long digression into XML Layout files, but as you can see, that is where a lot of the initialization of the application’s user interface takes place: where views are defined, named, and given attributes; where the screen is layed out; and where hints are given to the layout manager describing the way we would like the screen to look.

Android Application Development : Initialization in MicroJobs.java (part 1)

Having seen the XML resources that Android uses to launch the application, we can turn to some Java code that initializes the application. Use Eclipse to open MicroJobs.java in the Java editor.

Android Application Development : Initialization Parameters in AndroidManifest.xml

The MicroJobs Activity is identified in the manifest at the beginning of the file. This part of the file is normally created in Eclipse when you first create the Project that you use to write your application.

Buyer’s Guide : Android Device (Part 3) - Asus Eee Pad Transformer Prime, Samsung Galaxy Tab 2 10.1, Asus Eee Pad Transformer Infinity

The Galaxy Tab 10.1 was one of the few on the market that could directly compete with the iPad 2, but Samsung felt it could do better. Enter the Galaxy Tab 2 10.1. It’s as thin as the previous Galaxy Tab 10.1 (thinner than the iPad 2), but now it has a redesigned form, a micro-SD slot, TV remote control capabilities and it’s substantially cheaper than its predecessor.

Buyer’s Guide : Android Device (Part 2) - Sony Tablet S, Acer Iconia Tab A200, Lenovo ThinkPad Tablet

Although the appearance of the Sony Tablet S is unlike any other on the market, beneath the case there’s something far more familiar going on. A 1GHz dual-core Tegra 2, 1GB of memory and an SD card slot. Front and rear cameras, and a 9.4” screen with 1280 x 800 resolution.

Buyer’s Guide : Android Device (Part 1) - Google Nexus 7, Samsung Galaxy tab 2 7.0

It might not have the coolest name around, but the Samsung Galaxy Tab 2 7.0 is perhaps the only device around at the moment that can five the Nexus 7 any real comperition – especially since the Kindle Fire hasn’t yet made it to the UK.