Create Android App With Java

Create Your Javafx Application

Navigate to /src/< platform> /java and begin developing your JavaFx application! Application resources are stored in /src/< platform> /resources.

You can start with a simple Hello World application or look at the source code that I have put together here. OnyxFx is an application I made, following these instructions, that makes REST calls over HTTP to the OnyxFxAPI. The API, in turn, is a web scraper that will return the statistical data for the NBA® player and season the client specifies. It returns the data as JSON, which is then parsed and displayed to the screen of the mobile app. Feel free to edit it!

Keep in mind that although you can share source code, you should include custom edits in each copy of the source, should you want to make device specific changes.

Also note that the underlying compiler does not fully support all Java 8 APIs. If you look very closely at my source code, you will notice that in the iOS version of the source code, I have removed unsupported API such as java.util.function.BiConsumer and java.util.Map.replace.

Create The Applications Directory Structure

To automate the process of creating these directories, execute the following shell script.

Bourne-Again Shell / Korn Shell:

Windows Shell :

Save the file as mkpdir.bat or mkpdir.sh and execute the file from the projects root directory as root .

# *.nixchmod +x mkdir.sh-sh ./mkpdir.sh

# Windowsmkpdir

Notice that we created directories for embedded and desktop. We will produce a desktop build, because it takes no additional work to do so. However, we will not produce any builds for embedded devices.

Implementing Logic Using Java

After the front-end elements are finalized, the most important step remains implementing logic for all the activities to work well. The logic needs to be implemented in the MainActivity.java file from the src/com.example.tutorialapplication/ folder. The MainActivity.java file is the file that actually get converted into Dalvik compatible format and runs the application.

Let us consider that you created the front end to have a text field that displays Udemy Online Courses and here is the code snippet for this text display in the application.

This code snippet is for the MainActivity.java file.

In the above snippet, the R.layout.activity_main element calls the activity file. The onCreate and onCreateOptionsMenu are one of the many methods that are executed when MainActivity.java file executes.

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Is It Necessary For Developers To Learn Kotlin

Again, there are mixed opinions.

While it is not entirely necessary for developers to make the switch to Kotlin, theyre going to encounter the language eventually. If youre already familiar with Java, learning Kotlin will be simple. The language is poised to impact app development on a massive scale, so it doesnt hurt to learn the basics of the language. Additionally, growing with modern techniques and development styles will aid the growth of any developers skill set.

An Overview To The Kotlin Technology

Kotlin is a programming language that JetBrains developed in 2010, and its open-source. Kotlin can be used on Android, iOS applications development projects as well as desktop apps. It provides interoperability with Java, which means you can use their existing skills and knowledge of Java this also enables them to use Kotlin for Android application development projects.

• The top-5 programming languages developers are planning to adopt are Go, Kotlin, TypeScript, Python, and Rust.
• In just 3 years, Kotlin is now utilized by 7.8% of the industry specialists.
• Kotlin is used by global brands like Google, NetFlix, Amazon, Trello, and more.

Kotlin Key Features:

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Change The Background Color Of The Layout

Give your new activity a different background color than the first activity:

< color name="screenBackground2"> #26C6DA< /color> 

In the Attributes panel:

Or in XML:

Your app now has a completed layout for the second fragment. But if you run your app and press the Random button, it may crash. The click handler that Android Studio set up for that button needs some changes. In the next task, you will explore and fix this error.

Examine The Navigation Graph

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 fragments, and a navigation graph to connect the two. It also set up a button to send a string argument from the first fragment to the second. This 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 fragments with some arrows between them. You can zoom with + and – buttons in the lower right, as you did with the Layout Editor.

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Add Image To The Ui Layout

Now let’s add a droid image to our layout.

Knowledge Of The Application Components

Application components are the essential building blocks of Android app development. Each of the components is a different point by which the system can enter your app. Although each one of them exists as its own entity and plays a specific role, there are some which depend on each other, and not all of them are actual entry points.

There are five different types of app components each serving a distinct purpose with a distinct life cycle which defines how it is created and destroyed. They include:

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Change Text Display Properties

A menu pops up with possible completion values containing the letter g. This list includes predefined colors.

Below is an example of the textAppearance attributes after making some changes.

My First App: How To Create Your First Android App Step By Step

To create a native Android app, one that can directly use all the features and functionality available on an Android phone or tablet, you need to use the Android platform’s Java API framework. This is the API that allows you to perform common tasks such as drawing text, shapes, and colors on the screen, playing sounds or videos, and interacting with a device’s hardware sensors. Over the years, the Android API framework has evolved to become more stable, intuitive, and concise. As a result, being an Android developer today is easier than evereven more so if you use Android Studio, the official tool for working with the framework.

In this tutorial, I’ll show you how to create your first Android app. While doing so, I’ll also introduce you to important Android-specific concepts such as views, layouts, and activities.

We’ll be starting from scratch to create a very simple app in this tutorial. If you prefer writing less code or need to develop your app as quickly as possible, however, consider using one of the native Android app templates available on CodeCanyon.

Using an app template, you can have a polished, ready-to-publish app in just a matter of hours. You can learn how to use an Android app template by referring to the following tutorial:

To be able to follow along, you’ll need:

• the latest version of Android Studio
• a device or emulator running Android Marshmallow or higher

• Ashraff Hathibelagal

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Providing Text Element In The Strings File

All the textual elements used in the UI of the app are provided in the Strings file. This includes button names, labels, default text on-screen, and so on. The following code snippet shows the default string declarations:

< resources> < string name="app_name"> Udemy Online Courses< /string> < string name="udemy_courses">  Udemy Online Courses!< /string> < string name="menu_settings"> Settings< /string> < string name="title_activity_main"> MainActivity< /string> < /resources> 

Create A Shared Module For Cross

The cross-platform code that is used for both iOS and Android is stored in the shared module. Kotlin Multiplatform provides a special wizard for creating such modules.

In your Android project, create a Kotlin Multiplatform shared module for your cross-platform code. Later you’ll connect it to your existing Android application and your future iOS application.

The wizard will create the Kotlin Multiplatform shared module, update the configuration files, and create files with classes that demonstrate the benefits of Kotlin Multiplatform. You can learn more about the project structure.

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Use C Or C++ For Android Game Development

The Android operating system is designed to support applications written in Java or Kotlin, benefiting from tooling embedded in the system’s architecture. Many system features, like Android UI and Intent handling, are only exposed through Java interfaces. There are a few instances where you may want to use C or C++ code via the Android Native Development Kit despite some of the associated challenges. Game development is an example, since games typically use custom rendering logic written in OpenGL or Vulkan and benefit from a wealth of C libraries focused on game development. Using C or C++ might also help you squeeze extra performance out of a device to achieve low latency or run computationally intensive applications, such as physics simulations. The NDK is not appropriate for most novice Android programmers however. Unless you have a specific purpose for using the NDK, we recommend sticking with Java, Kotlin, or one of the cross-platform frameworks.

To create a new project with C/C++ support:

To learn more, about adding C and C++ code to your project, see the Android developer guide. To find Android NDK samples with C++ integration, see the Android NDK samples repo on GitHub. To compile and run a C++ game on Android, use the .

# Add Required Android App Permissions And Features

The Bambuser broadcasting library for Android requires at least the following permissions forbasic functionality:CAMERA

Additionally, to achievesuitable filteringof your app in the Google Play store, you should declare < uses-feature /> tags relevant for appsthat rely on the camera.

• Open the manifests/AndroidManifest.xml file in the Project tree on the left.

• Add the following tags for permissions and features, before the < application /> tag:

< uses-permissionandroid:name="android.permission.CAMERA"/> < uses-permissionandroid:name="android.permission.RECORD_AUDIO"/> < uses-permissionandroid:name="android.permission.INTERNET"/> < uses-permissionandroid:name="android.permission.WAKE_LOCK"/> < uses-permissionandroid:name="android.permission.ACCESS_NETWORK_STATE"/> < uses-featureandroid:name="android.hardware.camera.any"android:required="true"/> < uses-featureandroid:name="android.hardware.camera"android:required="false"/> < uses-featureandroid:name="android.hardware.camera.autofocus"android:required="false"/> < uses-featureandroid:name="android.hardware.camera.flash"android:required="false"/> < uses-featureandroid:name="android.hardware.camera.front"android:required="false"/> 

Since Android 6.0, the above is not enough. Certainpermissions must be approvedby the end-user at runtime. In the generated MainActivity.java, check for and request anymissing permissions:

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Tutorial: Create Your First Android Application

In this tutorial, we will create a simple yet fully-functional Android application that counts how many times you tap a droid image. After that, we will run it on an Android virtual device.

This tutorial covers a simple scenario to help you get started with Android development in IntelliJ IDEA. For comprehensive how-to guides and reference documentation, visit the Android Studio user guide.

Create A Virtual Device

In this task, you will use the Android Virtual Device manager to create a virtual device that simulates the configuration for a particular type of Android device.

The first step is to create a configuration that describes the virtual device.

Note: System images can take up a large amount of disk space, so just download what you need.

The AVD Manager now shows the virtual device you added.

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Make The Count Button Update The Number On The Screen

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 it is pressed, the number on the screen increases by 1.

view.findViewById.setOnClickListener }) 

private void countMe 

   ...    // Get the value of the text view    String countString = showCountTextView.getText.toString 

   ...    // Convert value to a number and increment it    Integer count = Integer.parseInt     count++ 

   ...   // Display the new value in the text view.   showCountTextView.setText) 

Here is the whole method:

private void countMe 

Creating Your Game View

You may be used to apps that use an XML script to define the layout of views like buttons, images and labels. This is what the line setContentView is doing for us.

But again, this is a game meaning it doesnt need to have browser windows or scrolling recycler views. Instead of that, we want to show a canvas instead. In Android Studio a canvas is just the same as it is in art: its a medium that we can draw on.

So change that line to read as so:

setContentView)

Youll find that this is once again underlined red. But now if you press Alt+Enter, you dont have the option to import the class. Instead, you have the option to create a class. In other words, were about to make our own class that will define whats going to go on the canvas. This is what will allow us to draw to the screen, rather than just showing ready-made views.

So right click on the package name in your hierarchy over on the left and choose New > Class. Youll now be presented with a window to create your class and youre going to call it GameView. Under SuperClass, write: android.view.SurfaceView which means that the class will inherit methods its capabilities from SurfaceView.

In the Interface box, youll write android.view.SurfaceHolder.Callback. As with any class, we now need to create our constructor. Use this code:

private MainThread thread public GameView 

Now override some methods:

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Do You Need To Develop An Android App

In this article, weve been giving out some ideas on creating Android apps that require different kinds of development know-how. Still, if you need help with programming Android apps, have you thought about relying on Yeeply?

Well get you in contact with the Android development professionals who match your project best to ensure that your Android app is ready sooner than you might imagine. Publish your project and well help you out!

Editors note: This article was originally published in May 2015 and has been updated for freshness, accuracy and comprehensiveness.

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Explore And Resize The Component Tree

This panel shows the view hierarchy in your layout, that is, how the views are arranged in relation to each other. 2. If necessary, resize the Component Tree so you can read at least part of the strings. 3. Click the Hide icon at the top right of the Component Tree.

The Component Tree closes. 4. Bring back the Component Tree by clicking the vertical label Component Tree on the left.

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