{"id":37896,"date":"2016-06-17T15:00:29","date_gmt":"2016-06-17T12:00:29","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=37896"},"modified":"2023-11-09T15:21:08","modified_gmt":"2023-11-09T13:21:08","slug":"android-tutorial-beginners-with-examples","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/android\/android-tutorial-beginners-with-examples\/","title":{"rendered":"Android Tutorial For Beginners With Examples"},"content":{"rendered":"

There are lots of reasons why more and more people are interested in learing how to be able to develop Android applications. Unarguably, Android is the most popular mobile operating system<\/strong>, with almost 2 billion devices activated and it offers a unified approach to application development for mobile devices.<\/p>\n

That means, that developers need only develop for Android, and their applications will be able to run on different devices powered by Android. This particular asset gives Android endless possibilites! This means that and application that is designed to work on mobile phone devices can be also transfered to Android powered TV sets or Android Car systems.<\/p>\n

This is why, Android is an exciting space to make apps that can help you in every aspect of your life, can help you communicate, organize, educate, entertain or just to make your life easier in every device that they might run on!
\n[ulp id=’Ja8Orb5oPKdShcXt’]<\/span><\/p>\n

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Table Of Contents<\/h3>\n
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1. What is Android<\/a><\/dt>\n
2. Installing Android Studio<\/a><\/dt>\n
3. Android versions and Android SDK Manager<\/a><\/dt>\n
4. Supporting different screen sizes<\/a><\/dt>\n
5. Android Project Structure<\/a><\/dt>\n
6. Create \u201cHello Android World\u201d application<\/a><\/dt>\n
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6.1. Create a New Android Studio Project<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.2. Create the source code of a simple FirstAndroidApplication Activity<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.3. Create the layout of the project<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.4. Android Manifest<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.5. Edit the FirstAndroidApplication dimensions<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.6. Edit the FirstAndroidApplication strings<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.7. Add the drawable for every screen density<\/a><\/dt>\n<\/dl>\n<\/dd>\n
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6.8. Build, compile and run<\/a><\/dt>\n<\/dl>\n<\/dd>\n
7. Download the Android Studio Project<\/a><\/dt>\n
8. How to continue?<\/a><\/dt>\n<\/dl>\n<\/div>\n

In this special example, we are going to set our Android Development Studio IDE<\/strong>, make our very first Android application<\/strong> and discover the Android Development world<\/strong> in the easiest possible way.<\/p>\n

The mobile development world can be very fun, because the direct results we see when creating our own application, can be highly motivating and rewarding.<\/p>\n

<\/a>1. What is Android?<\/h2>\n

Android is a mobile operating system currently developed by Google, based on the Linux kernel and designed primarily for touchscreen mobile devices such as smartphones and tablets. And as we said before, Android offers a unified approach to application development for mobile devices.<\/p>\n

Android is an open-source operating system named Android. Google has made the code for all the low-level “stuff” as well as the needed middleware to power and use an electronic device, and gave Android freely to anyone who wants to write code and build the operating system from it. There is even a full application framework included, so third-party apps can be built and installed, then made available for the user to run as they like.<\/p>\n

The “proper” name for this is the Android Open Source Project, and this is what people mean when they say things like Android is open and free. Android, in this iteration, is free for anyone to use as they like.<\/p>\n

<\/a>2. Installing Android Studio<\/h2>\n

In order to write an Android application, we are going to need a development environment. Google has made a very useful tool for all Android Developers, the Android Studio<\/strong>. Android Studio is the official IDE for Android development, and with a single download includes everything you need to begin developing Android apps. Included in the download kit, are the Software Development Kit (SDK)<\/strong>, with all the Android libraries<\/strong> we may need, and the infrastructure to download the many Android emulator<\/strong> instances, so that we can initially run our application, without needing a real device.<\/p>\n

So, we are going to download and install Android Studio.<\/p>\n

Tip<\/strong>
\nFirst we have to have installed the Java Development Kit (JDK) from Oracle. If you do not, please you should download the latest JDK from the Oracle’s special section<\/strong><\/a> here.<\/div>\n

\"Android<\/a>
Android Studio Installation – step 1<\/figcaption><\/figure>
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\"Android<\/a>
Android Studio Installation – step 2<\/figcaption><\/figure>
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\"Android<\/a>
Android Studio Installation – step 3<\/figcaption><\/figure>
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\"Android<\/a>
Android Studio Installation – step 4<\/figcaption><\/figure>
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\"Android<\/a>
Android Studio Installation – step 5<\/figcaption><\/figure>
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\"Android<\/a>
Android Studio Installation – Ready<\/figcaption><\/figure><\/p>\n

<\/a>3. Android versions and Android SDK Manager<\/h2>\n

Google, releases almost every year (or even sooner than a year), a new Android version<\/strong> in order to update the mobile operating system, so that it contains new features and possibilities<\/strong> and of course to fix things that might not work in the right way.<\/p>\n

So, each version of Android has it\u2019s own SDK<\/strong> (software development kit), so that we can use to build apps that can run on and include all the latest features Android has added in its latest versions.<\/p>\n

This means that it is essential that we keep up updating our applications with the latest features all the time, and if possible, without losing the consistency of the previous Android versions.<\/p>\n

As part of the Setup Wizard you will already have the latest SDK available to you, however it\u2019s useful to know how to install additional SDK\u2019s if you need to work with older devices that do not run the latest version of Android.<\/p>\n

SDK\u2019s allow you to create AVD\u2019s (Android Virtual Devices) to test your Apps on, customized to your personal configuration. Want to see how your Android App looks on a TV sized screen? If you have a screen big enough you can find out.

<\/div> <\/div><\/p>\n

<\/a>4. Supporting different screen sizes<\/h2>\n

Android runs on a variety of devices that offer different screen sizes and densities<\/strong>. This means that Android can handle applications that run on small mobile phone devices, as well as applications that run on large tablet densities.<\/p>\n

This feature gives Android a great advantage, but also, although the system performs scaling and resizing on different screens, developers should make the effort to optimize their application for different screen sizes and densities. Android system provides a consistent development environment across devices and handles most of the work to adjust each application’s user interface to the screen on which it is displayed. At the same time, the system provides APIs that allow you to control your application’s UI for specific screen sizes and densities, in order to optimize your UI design for different screen configurations. For example, you might want a UI for tablets that’s different from the UI for handsets.<\/p>\n

Below is an introduction to the terms and concepts used, a summary of the screen configurations that the system supports, and an overview of the API and underlying screen-compatibility features:<\/p>\n

Screen size<\/strong>
\nActual physical size, measured as the screen’s diagonal.
\nFor simplicity, Android groups all actual screen sizes into four generalized sizes: small, normal, large, and extra-large.<\/p>\n

Screen density<\/strong>
\nThe quantity of pixels within a physical area of the screen; usually referred to as dpi (dots per inch). For example, a “low” density screen has fewer pixels within a given physical area, compared to a “normal” or “high” density screen.
\nFor simplicity, Android groups all actual screen densities into six generalized densities: low, medium, high, extra-high, extra-extra-high, and extra-extra-extra-high.<\/p>\n

Orientation<\/strong>
\nThe orientation of the screen from the user’s point of view. This is either landscape or portrait, meaning that the screen’s aspect ratio is either wide or tall, respectively. Be aware that not only do different devices operate in different orientations by default, but the orientation can change at runtime when the user rotates the device.<\/p>\n

Resolution<\/strong>
\nThe total number of physical pixels on a screen. When adding support for multiple screens, applications do not work directly with resolution; applications should be concerned only with screen size and density, as specified by the generalized size and density groups.<\/p>\n

Density-independent pixel (dp)<\/strong>
\nA virtual pixel unit that you should use when defining UI layout, to express layout dimensions or position in a density-independent way.
\nThe density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a “medium” density screen. At runtime, the system transparently handles any scaling of the dp units, as necessary, based on the actual density of the screen in use. The conversion of dp units to screen pixels is simple: px = dp * (dpi \/ 160). For example, on a 240 dpi screen, 1 dp equals 1.5 physical pixels. You should always use dp units when defining your application’s UI, to ensure proper display of your UI on screens with different densities.<\/p>\n

Android provides support for multiple screen sizes and densities, reflecting the many different screen configurations that a device may have. You can use features of the Android system to optimize your application’s user interface for each screen configuration and ensure that your application not only renders properly, but provides the best user experience possible on each screen.<\/p>\n

To simplify the way that you design your user interfaces for multiple screens, Android divides the range of actual screen sizes and densities into sizes: small, normal, large, and xlarge<\/p>\n

A set of six generalized densities:<\/p>\n