Apps development for Android step by step
Below you will find recent lessons. You could also check list of all Android lessons available as well as alphabetic index of Android java keywords and XML tags.
Problems with Android Studio after upgrade? Read Google troubleshooting. There you will find how to deal with error: Gradle 'basic' project refresh failed.

Lesson 1.2: Keeping text in a dedicated file (why and how to use strings.xml file in Android)

Our first app displays “I’m the best” on the screen. To achieve that goal we’ve used TextView tag and modified its android:text attribute. This attribute could keep a specific text (that we did in previous lesson) or reference to one of strings in a file dedicated for keeping all text.

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Lesson 1.1: My first app: More than Hello world! (TextView tag and android:text attribute)

If you want to create an app displaying on the screen “Hello world!” (a standard text for the first application), just… start a new project in Android Studio. It already includes Hello world! functionality. But what to do to display “I’m the best!” instead?

There are two ways of doing it: very simple and… recommended one (but still simple). Firstly, you have to start a new project or open the one created in Lesson 0 and then find again activity_main.xml file in layout subfolder (you could learn how to open that file from Lesson 0). Now click Text tab at the bottom of the activity_main.xml file window. You should see the code of layout of your first app.

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Lesson 1: How to display and format a text in Android apps

In this lessons set we will write and display some text in Android app.  And then we will make this text look as we wish. We assume that you know how to create a new app project and find activity_main.xml file. Otherwise start with Lesson 0.

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Appendix A: Android XML syntax – structure of XML tags and attributes

XML files are used to define layout of Android apps and store data. Tags decide what elements would be used for app interface (like strings, images and buttons), how they would look like and what values would they have.

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Lesson 0.7: Running an Android app in a real device (but you don’t need any to create an app)

It’s difficult to test your app on dozens various devices, so described in previous lesson emulators are really helpful. But if you have any real Android device, you could run on it your apps. You don’t need to register anywhere or buy anything to do it (by the way those steps are necessary to create and test iOS apps).  All you need beside your phone or tablet is a USB cable (usually delivered with device) and USB driver (available for free in Internet).

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