There are two fundamental protocols in the transport layer 1. TCP Transmission Control Protocol-- connection-oriented protocol 2. UDP User Datagram Protocol -- connectionless protocol Connection-oriented communication : establishes a logical (virtual) connection prior to sending data. Connectionless communication : sends data right away without establishing a logical connection Qn why do we have transport layer protocal? IP provides a weak, but efficient service model (best-effort ) How should hosts send into the network? i.)Flow Control ii.) Too fast is bad; too slow is not efficient IP packets are addressed to a host How to decide which application gets which packets? NOTE TRASPORT LAYER IS RESPONSIBLE FOR PROCESS TO PROCESS DELIVERY PORTS port is a communication endpoints Since there are many applications running on a computer, there is a need to decide which application gets which packet. A port number is a way to identify a specific application (proc
Developer Guides
Welcome to the Android developer guides. These documents teach you how to build Android apps using APIs in the Android framework and other libraries. If you're brand new to Android and want to jump into code, start with the Build Your First App tutorial. And check out these other resources to learn Android development: Codelabs: Short, self-paced tutorials that each cover a discrete topic. Most codelabs step you through the process of building a small app, or adding a new feature to an existing app. Courses: Guided training paths that teach you how to build Android apps. Online training: If you prefer to learn online with videos, check out the Developing Android Apps with Kotlin course on Udacity (trailer embedded here), and other online courses below. Otherwise, the following is a small selection of essential developer guides that you should be familiar with.
Let get started with frist android app
What is Android?
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. 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. 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.
Steps one- First 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 sectionhere
- Then download android studio in a faster internet speed
Android Project Structure
Before we try to make our first Android application, we should first see the basic parts of an Android application project, in order to recognize them and be able to understand them better. Activities The Activities are the main Java classes, that contain the Android code with which we are going to develop, what do we want the application to do
• Layouts The Layouts are the main xml files, that contain the Android xml code with which we are going to develop, how will our application views look like. • Values The Layouts are the main xml files, that contain the Android xml code with which we are going to develop, how will our application views look like. – Animation Resources – Color State List Resource – Drawable Resources – Layout Resource – Menu Resource – String Resources – Style Resource • Drawables A drawable resource is a general concept for a graphic that can be drawn to the screen. There are several different types of drawables: – Bitmap File A bitmap graphic file (.png, .jpg, or .gif). Creates a BitmapDrawable. – Nine-Patch File A PNG file with stretchable regions to allow image resizing based on content (.9.png). Creates a NinePatchDrawable. – Layer List A Drawable that manages an array of other Drawables. These are drawn in array order, so the element with the largest index is be drawn on top. Creates a LayerDrawable. – State List An XML file that references different bitmap graphics for different states (for example, to use a different image when a button is pressed). Creates a StateListDrawable. – Level List An XML file that defines a drawable that manages a number of alternate Drawables, each assigned a maximum numerical value. Creates a LevelListDrawable. – Transition Drawable An XML file that defines a drawable that can cross-fade between two drawable resources. Creates a TransitionDrawable. – Inset Drawable An XML file that defines a drawable that insets another drawable by a specified distance. This is useful when a View needs a background drawble that is smaller than the View’s actual bounds. – Clip Drawable An XML file that defines a drawable that clips another Drawable based on this Drawable’s current level value. Creates a ClipDrawable. – Scale Drawable An XML file that defines a drawable that changes the size of another Drawable based on its current
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