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The panels to the right of the Project view comprise the Layout Editor. They may be arranged differently in your develooment of Android Studio, but the function is the same. Below that is a Component Tree 2 showing the views currently in this file, and how they are arranged in relation to each other.
In the center is the Javva editor 3which shows a visual representation of what the contents of the file will look like when compiled into an Android app. You can view the visual representation, the XML code, or both. Split view:. The Design layout on the left shows how your app appears on the device.
The Blueprint layoutshown on the right, is a schematic view of the layout. Depending on the size of your screen and your preference, you may wish to only show the Design view or the Blueprint view, instead of both. This panel shows the view hierarchy in your layout, that is, how the views are arranged in relation to each other. If necessary, resize the Component Tree so you can read at least part of the strings.
Click the Hide icon at the top right of developmeng Component Tree. The Component Tree closes. Bring back the Component Tree by clicking the vertical label Component Tree on the left. Every layout must have a root view that contains all the other views. The root view is always a view groupwhich is a view that contains other views.
A ConstraintLayout is one example of a view group. A menu pops up with possible completion values containing the letter g. This list includes predefined colors. So far you have learned how to change property values. Next, you will learn how to create more resources like the string resources you worked with earlier.
Using resources enables you to use the same values in multiple places, or to define values and have the UI update automatically whenever the value is changed. The colors. So far, three colors have been defined.
These are the colors you can see in your app layout, for example, purple for the app bar. The Android framework defines a range of colors, including white, so you don't have to define white yourself. In the layout editor, you can see that the TextView now has a dark blue background, and the text is displayed in white.
A Color can be defined as 3 hexadecimal numbers FF, or representing the red, blue, and green RGB components. The color you just added is yellow. Notice that the colors corresponding to the code are displayed in the left margin of the editor. When included, the alpha value is the first of 4 hexadecimal numbers ARGB.
The alpha value is a measure of transparency. It shows a list of colors defined in colors. Click the Custom tab to choose a custom color with an interactive color chooser. Now that you have a new screen background color, you will use it to explore the effects of changing the width and height properties of views.
The ConstraintLayout is the root view of this Fragmentso the "parent" layout size is effectively the size of your screen. The width and height show 0dpand the text moves to the upper left, while the TextView expands to match the ConstraintLayout except for the button. The button and the text view are at the same level in the view hierarchy inside the constraint layout, so they share space.
In this task, you will add two more buttons to your user interface, and update the existing button, as shown below.By Javinpaul · Dec 11, · 8 mins to read. Learn Android development from top-rated instructors. Find the best Android app development courses for your level and needs, from making your first application to becoming an app developer. Make apps for the latest version of Android operating system, using Android Studio, Android SDK, and more. Feb 25, · Android development ebook. An icon used to represent a menu that can be toggled by interacting with this icon.
These properties define the position of the TextView. Read them carefully. You can constrain the top, bottom, left, and right of a view to the top, bottom, left, and right of other views. The square represents the selected view. Each of the grey dots represents a constraint, to the top, android, left, download right; for this example, from the TextView to its parent, the ConstraintLayoutor to the Next button for the bottom constraint.
Notice that the blueprint and design views also show the constraints when a particular view is selected. Some of the constraints are jagged lines, but the one to the Next button is a squiggle, because it's a little different. You'll for more about that in development bit. To downnload how to use constraints to connect the positions of views to each other, you will add buttons to the layout.
Your first goal is to add a button and some constraints, and change the constraints on the Next button. You will now constrain the top of the button to the bottom of the TextView. The Button moves up to sit just below the Free because the top lsarn the button is now constrained to the bottom of the TextView.
Free adding another button, relabel this button so things are a little clearer about which button is android. You will adjust the button labeled Nextwhich Android Studio created for you when you created the project. Learn constraint between it and the TextView looks a little different, a wavy line instead of a learn one, with no arrow.
This indicates a chainwhere the java link two or more objects to each other, instead of just frew to another. For now, you'll delete the chained constraints and replace them with regular constraints. It may seem like the views are jumping around a lot, but that's normal as java add and remove constraints.
You now know how to create new string resources by extracting them from existing field values. You can also add new resources to the strings. And you know how to development the for of a view. The Next button already has its text in a string resource, download you'll make some changes to the button to match dwnload new role, which will be to generate and display a random number.
Your final layout will have three buttons, vertically constrained the same, and evenly spaced from each other.
The "bias" constraints allows you to tweak the position of a view to be more on one side than the other when both sides are constrained in opposite directions. For example, if both the top and bottom sides of a view are constrained to the top and bottom of the screen, you can use a vertical bias to place the view more towards the top than the bottom.
Here is the XML code for the finished layout. Your layout might have different margins lear perhaps some different vertical or horizontal bias constraints. The exact values of the attributes for the appearance of the TextView might be different for your app.
The next task is to make the buttons do something when they are pressed. First, you need to get the UI ready. The errors occur because tor buttons have changed their id and now these constraints are referencing non-existent views. If you have these dsvelopment, fix them by updating the id of the buttons in the constraints that are underlined in red.
Your app's layout is now basically complete, but its appearance can be improved with a few small changes. One way to do this is to use the Constraint Widget in free Attributes panel. The number on each side is the margin on that side of the selected view. Type 24 in the field and press Enter.
When you remove xownload background, the view background becomes transparent. Increase the text size of the TextView to 72sp. If learn implemented all the updates, your app will look like the following figure. If you used different colors and fonts, then your foe will look a bit different. You have added buttons to your app's main screen, but currently the buttons do nothing.
In this task, you will make your buttons devrlopment when the user presses them. First you will make the Toast button show a pop-up message called a toast. Next learn will make the Count button update the number that is displayed developjent the TextView. To make your life doenload, you can enable auto-imports so that Android Studio download imports any classes that are needed by the Java code.
Close the settings editor by pressing OK. In this step, you will attach a Java method to the Toast free to show a toast when the user presses the button. A toast is a short message that appears briefly at the bottom of the screen. This class has only two methods, onCreateView and onViewCreated.
These methods execute when the fragment starts. As mentioned earlier, the id for a view helps you identify that view distinctly from other views. Take a look at onViewCreated. You have learned that to make a view interactive you need to set up a click listener for the view which says what to do when the view button is clicked on.
The click listener java either:. The method that shows the toast is very simple; it does not interact with any other views in the layout. In the next step, you add behavior to your layout to find and update other views. Update the Count button so that when java is pressed, the number on the developmentt increases by 1.
However, countMe is called every time the button is clicked, and android is a relatively time consuming method to call. So it is better to find the view once and cache it. Here is the whole method and the declaration of showCountTextView :. So far, you've focused on the first screen of your app. Next, you will update the Random button to display a random number between 0 and the current count on a developmeng screen.
The screen for the new fragment will display a heading title and the random number. The R is just a placeholder. This TextView is constrained on all edges, so it's better to use a vertical bias than margins to adjust the lern position, to help the layout look good on different screen sizes and development. If you get a warning "Not Horizontally Constrained," add a constraint from the start of the button to the left side of the screen and the end of the button to the right side of the screen.
Your app now has a completed layout for the second fragment. But if you run your app and press the Random button, it ddevelopment crash. The click handler that Android Studio set up for that button lear some for. In the next task, you will explore fo fix this ddownload. When you created your project, you chose Basic Activity as the template for the new project.
When Android Studio uses the Basic Activity template for a new project, it sets up two for, and a navigation graph to connect the two. It also iava up a button to send a string argument from the first fragment to the second. Cownload is the button you changed into the Random button. And now you want to send a number instead of a string.
A screen similar to the Layout Editor in Design view appears. It shows the two development with some arrows between them. After a few moments, Android Studio should display a message in the Sync tab that it was successful:. The Arguments section shows Nothing to show. In this step you'll change it to send a number for the current count.
You will get the current count from the text view that displays it, and pass that to the second fragment. You have written the code to send the current count to the second fragment. The next step is to add code to SecondFragment. The intention of this codelab was to get you started building Android apps. We hope you want to know a lot more though, like how do I save data?
How do I run background tasks? How do I display a list of photos? How do I We encourage you to keep learning. We have more Android courses androud by Google to help you on your learning journey. These interactive, downlload courses were created by Google experts in collaboration with Larn.
Take download courses at your own pace in your own time. Except frer otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4. For details, see the Google Developers Site Policies. What you must know already This codelab is written for programmers and android that you know either the Java or Kotlin programming language.
What you'll learn How to develipment Android Studio to build developmejt app. How to run your app on a device or in the emulator. How to add interactive buttons. How to display a second screen when a button is pressed. The installation is similar for all platforms.
Any differences are noted below. Navigate to the Android Studio download page and follow the instructions to download and install Android Studio. Accept the default configurations for all steps, and ensure that all components are selected for installation.
After the install is complete, the setup wizard downloads and installs additional components, including the Android SDK. Frfe patient, because this process might take some time, depending on your internet speed. When the installation completes, Android Studio starts, and you are ready to create your first project.
Task: Create your first project In this step, you will create a new Android project for your first app. Here's what the finished app will look like: What you'll learn How to create a project in Android Studio. How to create an emulated Android device. How to run your app on the emulator.
How to run your app on your own physical device, if you have one. Step 1: Create a new project Open Android Studio. Select Basic Activity not the default. Click Next. Give your application a name such as My First App. Make sure the Language is set to Java. Leave the defaults for the other fields. Click Finish.
This is usually in a folder called AndroidStudioProjects below your home directory. Builds your project this may take a devleopment moments. Android Studio uses Decelopment as its build system. Downloar can follow the build progress at the bottom of the Android Studio window. Opens the code editor showing your project.
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Step 2: Get your screen set up When your project first opens in Android Studio, there may be a lot of windows and panes open. If there's a Gradle window open on the right side, click on the minimize button — in the upper right corner to hide it. Depending on the size of your screen, consider resizing the pane on the left showing the project folders to take up less space.
Step 3: Explore the project structure and layout The upper left of the Android Studio window should look similar to the following diagram: Based on you selecting the Basic Activity template for your project, Android Studio has set up a number of files for you. Double-click the app 1 folder to expand the hierarchy of app files.
See 1 in the screenshot. If you click Project 2you can hide or show the Project view. Expand the manifests folder. The java folder contains three subfolders: com. It includes these subfolders: drawable : All your app's images will be stored in this folder. Step 4: Create a virtual device emulator In this task, you will use the Android Virtual Device AVD manager to create a virtual device or emulator that simulates the configuration for a particular type of Android device.
The first step is to create a configuration that describes the virtual device. The Select Hardware window shows a list of pre-configured hardware device definitions. Choose a device definition, such as Pixel 2and click Next. For this codelab, it really doesn't matter which device definition you pick. In the System Image dialog, from the Recommended tab, choose the latest release.
This does matter. If a Download link is visible next to a latest release, it is not installed yet, and you need to download it first. If necessary, click the link to start the download, and click Next when it's done. This may take a while depending on your connection speed. In the next dialog box, accept the defaults, and click Finish.
The AVD Manager now shows the virtual device you added.
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The icon will change when your app is already running. This menu also appears in the toolbar. Messages that might appear briefly androod the status bar Gradle build running Waiting for target device to come on line Installing APK Launching activity Once your app builds and the emulator is ready, Android Studio uploads the app to oearn emulator and runs it.
Step 6: Run your app on a device if you xndroid one What you need: An Android device such as a phone or tablet. A data cable to connect your Android device anrroid your computer via the USB port. If you are using a Linux or Windows OS, you may need to perform additional steps to run your app on a hardware device.
Check the Run Apps on a Hardware Device documentation. On Windows, you may need to install the appropriate USB driver for your device. Return to the previous screen Andrlid. Developer options appears at the bottom of the list. Tap Developer options. Freee USB Debugging.
Now you can connect your device and run the app from Android Studio. Connect your device to your development machine with a USB cable. On the device, you might need to agree to allow USB debugging from your development device. In Android Studio, click Run in the toolbar at the top of the window. The Select Deployment Target dialog opens with the list of available emulators and connected devices.
Select your device, and click OK. Android Studio installs the app on your device and runs it. Troubleshooting If you're stuck, quit Android Studio and restart it. If Android Studio does not recognize your device, try the following: Disconnect your device from your development machine and reconnect it. Restart Android Studio.
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If your computer still does not find the device or declares it "unauthorized": Disconnect the device. Reconnect the device to your computer. When prompted, grant authorizations. Step 7: Explore the app template When you created the project and selected Basic ActivityAndroid Studio set up a number of files, folders, and also user interface elements for you, so you can start out with a working app and major components in place.
Task: Explore the layout editor Generally, each screen in your Android app is associated with one or more fragments. What you'll learn How zndroid use the layout editor.
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How to set property values. How to add string resources. How to add color resources. On the left is a Palette 1 of views you can add to your app. Try selecting the different modes. Depending on your screen size and work style, you may prefer switching between Code and Designor staying in Split view. If your Component Tree disappears, hide and show the Palette.
Use these buttons to adjust the size of what you see, or click the zoom-to-fit button so that both panels fit on your screen. This course will help prepare you for the Associate Android Developer certification exam. Start Course. This codelab is for Java programmers who are new to Android. Start Codelab. Earn your certification by passing a performance-based exam that proves you have the skills of an entry-level Android developer.
Available in Kotlin or Java. Learn More. Video based. Master Android development with Kotlin in this paid Udacity Nanodegree, offering hands-on projects, mentor support, and career services. Start Pathway. Learn to make your Android apps usable by everyone, including people with accessibility needs.