12/30/2023 0 Comments For android download Rectangle ProAndroid Studio does this automatically to show you the hierarchy of elements. There's a lot more going on than in the simplified example, but Android Studio does some things to help make the XML more readable, just as it does with your Kotlin code. This is what the XML in activity_main.xml looks like: Find the options for Code, Split, and Design views in the upper right of the Layout Editor.You might notice the app shows a TextView with "Hello World!" within a ConstraintLayout, as you have seen in previous projects created from this template.Open activity_main.xml ( res > layout > activity_main.xml).Simplified, the XML for the UI elements above might be something like this: Just as you can set attributes on UI elements using the Layout Editor (design), the XML elements can have attributes, too. Each element starts and ends with a tag, and each tag starts with a. The terms parent and child are sometimes used, but the context here is talking about parent views (viewgroups) containing children views, which in turn can contain children views.Įach UI element is represented by an XML element in the XML file. This is unrelated to the hierarchy of classes and subclasses that you learned earlier. NOTE: The visible UI hierarchy is based on containment, ie, one component has one or more components inside of it. It allows you to position or size child views in a flexible manner. Remember, ConstraintLayout is a subclass of ViewGroup. For example, a ConstraintLayout (the parent) can contain Buttons, TextViews, ImageViews, or other views (the children). You describe the view hierarchy of UI elements on the screen. Note those layouts are UI components themselves. The UI for an Android app is built as a containment hierarchy of components (widgets), and the on-screen layouts of those components. You may recall from earlier codelabs that other resources like strings for your app are also defined in an XML file called strings.xml. Because XML is extensible and very flexible, it's used for many different things, including defining the UI layout of Android apps. XML stands for eXtensible Markup Language, which is a way of describing data using a text-based document. You will be looking at, and editing the XML file that defines the UI layout for this app. Learning how to understand and modify UI layouts using XML will be important for you as an Android developer. Instead of using the Layout Editor which you're already familiar with, you will build the layout of your application by modifying the XML that describes the UI. Call the app "Tip Time", with a minimum API level of 19 (KitKat).To start, create a new Kotlin project in Android Studio using the Empty Activity template.Switch - an on/off toggle for choosing whether to round up the tip or not.RadioGroup - to group the radio button options.RadioButton - a selectable radio button for each tip option.TextView - to display text like the service question and tip amount.EditText - for entering and editing text. You will be using these UI elements that are provided by Android: In this pathway, you'll build a simple version of a tip calculator as an Android app.ĭevelopers will often work in this way-getting a simple version of the app ready and partially functioning (even if it doesn't look very good), and then making it fully functional and visually polished later.īy the end of this codelab, your tip calculator app will look like this: Internet connection to access the Android developer documentation.A computer with the latest stable version of Android Studio installed.The UI for a tip calculator Android app.How to build the layout for a simple form to take in user text input and choices.How to read and write XML layouts in Android.Able to create and run an Android app from a template in Android Studio.Making the app work and look more professional will be in the following codelabs. At the end of the codelab, you'll have a working UI for the app, but the app won't actually calculate the tip yet. In this codelab, you will be building the layout for a basic tip calculator app. Instead, please refer to the Android Basics with Compose course for the latest recommended practices. Caution: This codelab is out of date and no longer maintained.
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