Mobile App development

Using a PC Program Maintaing regular backups App backup for Rooted devices

HashSet is a collection framework that implements the Set interface and does not allow any duplicate values. A HashMap is a Hash table that implements the Map interface and maps a key to value. HashMap also does not allow duplicate keys but allows duplicate values in it. 1. Implementation Hierarchy 2. Data Storage 3. Duplicate Values 4. Null Values

Access modifiers in Java serve the purpose of limiting the access of particular entities in a program. Access modifier in Java is the reserve keyword which limits or allows particular entities such as classes, methods to be accessible by other entities in the program. It simpler words, it restricts the scope of the particular class, variable or method. There are 4 different types of entities 1. Default 2. Public 3. Private 4. Protected

Methods are the lines of code that performs a specific function in a program. Methods can either return a value or not return anything. The methods which do not return anything are of type void. The main advantage of methods in a program is code reusability.

An object is a real-world entity that has some characteristics and behavior. For example, in real-life a car is an object which has characteristics like brand name, color, engine type, average, etc, and attributes like drive, brake, stand. In Java, we can create objects with 6 different methods which are: By new keyword By newInstance() method of Class class By newInstance() method of constructor class By clone() method By deserialization By factory method

Encapsulation means the ‘encapsulating’ or ‘wrapping up’ of data. This is actually a mechanism that binds data together. When encapsulation is implemented, only the variables inside the class can access it. No class outside the current class can access the variables inside it. This is similar to the fact that no one except you can access the clothes inside your travel bag. You do remember we learned about access specifiers in Java.

Core Data is a framework that you use to manage the model layer objects in your application. It provides generalized and automated solutions to common tasks associated with object life cycle and object graph management, including persistence. Core Data typically decreases by 50 to 70 percent the amount of code you write to support the model layer. This is primarily due to the following built-in features that you do not have to implement, test, or optimize:

1. Add a multi-factor authentication feature 2. End-to-end encryption 3. Fingerprinting device 4. The power of the paperless banking

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Animations are a vital component in building beautiful UIs. Following are some of the basic properties of a view that can be animated: center alpha frame bounds transform backgroundColor contentStretch The syntaxes for UIView Animations are: UIView.animate(withDuration:, animations:) UIView.animate(withDuration:, delay:, animations:) UIView.animate(withDuration:, delay:, options:, animations:) UIView.animate(withDuration:, delay:, options:, animations:, completion:)

2 ways to add third party libraries or “modules” Download the compiled JAR of the module, from the developer website Or use a build tool that can manage module and dependencies for you.

Sorted : If we call sorted on an array it will return a new array that sorted in ascending order. Map : Mapping is similar to sort in that it iterates through the array that is calling it, but instead of sorting it changes each element of the array based on the closure passed to the method. Filter : It will return an array that has only elements that pass your filter specified in your closure. Reduce : It allows you to combine all the elements in an array and return an object of any type

swift 3, 4, 4,2 Synchronous means that thread that initiated that operation will wait for the task to finish before continuing. DispatchQueue.main.sync {} Asynchronous means that Completes a task in background and can notify you when complete means it will not wait. DispatchQueue.main.async {}

let fileName = downloadTask.originalRequest?.url?.lastPathComponent let path = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true) let documentDirectoryPath:String = path[0] let fileManager = FileManager() var destinationURLForFile = URL(fileURLWithPath: documentDirectoryPath.appending("/Folder")) //\(String(describing: fileName!)) fileManager.moveItem(at: location, to: destinationURLForFile)

When discussing a delegate I often see comparison with notifications, observing, and callbacks (closures or blocks). While solving many common problems this concepts are different. A protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. @protocol Delegate <NSObject> protocol Delegate : AnyObject