Category Archives: Apple

How to listen to events from react native?

By | August 14, 2018

Hi friends, This is essentially a continuation of this post http://www.coderzheaven.com/2018/08/10/how-to-create-a-custom-native-imageview-in-android-for-reactnative/ Now we will listen to a click event from the image we just created. For that we have to add the ClickListener to the image in Android. Add below methods to the java class On the React Native Side The whole java class will look like this.

How to create a custom native ImageView/View in Android or iOS for ReactNative?

By | August 10, 2018

Many times we need custom components from native. Here is a simple example on how to create a custom imageview in Android for react native. First we will start with the Android Version Android Create a class that extends SimpleViewManager. Write a setSrc method which accepts the source url from React Native. Implement ‘createViewInstance’ method in which you… Read More »

Awesome React Native Image Caching Libraries

By | August 4, 2018

Image Loading and caching had been a little bit pain in react native. In-fact react native didn’t had native support for caching. But after the recent release, there is now support for caching in iOS only. Still not for Android. You can read more about this from here https://facebook.github.io/react-native/docs/images.html#cache-control-ios-only Now these are the variety of options available. default:… Read More »

AutoConnect to Wi-Fi in iOS

By | May 5, 2018

Apple has introduced a new API in iOS 11 where you can directly connect to a Wi-Fi from with-in the app. For this code to work 1. you need to enable the networking capabilities in your provisioning profile. 2. Once you enable the networking profile in the provisioning profile, you need to regenerate and sign the app with… Read More »

Special characters that can be included in a Swift String ?

By | January 5, 2018

Special characters can be included in string literals using the following escape sequences: The following example shows how to use a few string literals: Swift 4 Escape sequence Meaning \0 Null Character \\ \character \b Backspace \f Form feed \n Newline \r Carriage return \t Horizontal tab \v Vertical tab \’ Single Quote \” Double Quote \000 Octal… Read More »

How to Count characters in a String in Swift 4?

By | December 20, 2017

To retrieve a count of the characters in a string, call the global countElements function and pass in a string as the function’s sole parameter: prints “sampleString has 32 characters” Note : Different Unicode characters and different representations of the same Unicode character can require different amounts of memory to store. Because of this, characters in Swift do… Read More »

How Type Safety is implemeted in Swift 4?

By | December 15, 2017

Swift 4 is a type-safe language which means if a part of your code expects a String, you can’t pass it an Int by mistake. As Swift 4 is type-safe, it performs type-checks when compiling your code and flags any mismatched types as errors. Playground execution failed: error: :6:6: error: cannot assign to ‘let’ value ‘myVar’ myVar =… Read More »

Class has not initialiser error in Swift – Solved.

By | August 14, 2017

Apart from other languages, when you write a class in Swift, It should have a initialiser. To solve this we have to write init() function in that particular class. Just like below. For example, look at the below class. Here we have 5 variables. The above error usually comes when you don’t initialize all variables in the class… Read More »

Custom TimerView in iOS – Swift

By | April 10, 2017

Hello everyone, Here in this tutorial I will show you how you can create a Custom View for Timer without any layout in Swift. Custom Timer Class Our Custom timer class will look like this Here I am passing the superview in which timerview is going to be placed as the parameter. Then I am creating a circle… Read More »

Core Image Tutorial in Swift

By | March 30, 2017

It allows developers to filter images in their apps. Advantages Core Image supplies 90+ filters. Powerful image filtering capabilities Core Image includes APIs for face detection Automatic image enhancements Custom effects through “chained” filters. You can get all kinds of effects, such as modifying the vibrance, hue, or exposure. It uses either the CPU or GPU to process… Read More »

How to record Audio using AudioRecorder in iOS Swift

By | February 10, 2017

Well, its really easy for recording audio in an iOS application. We will decalre two variables in our View Controller Request Permisson from the User Start Recording Set Delegate Finish Recording Note : Sometimes iOS Stops the recording when a phone call comes. In that case we need to handle this. Since the delegate is our viewcontroller we… Read More »

Error Handling in Swift

By | October 1, 2016

When calling a method that may cause a failure, you normally pass it with an NSError object (as a pointer). If there is an error, the object will be set with the corresponding error. You then check if the error object is nil or not and respond to the error accordingly. That’s how you handle errors in Swift… Read More »

Create PDF in iOS

By | September 7, 2016

The UIKit framework provides a set of functions for generating PDF content using native drawing code. These functions let you create a graphics context that targets a PDF file or PDF data object. You can then create one or more PDF pages and draw into those pages using the same UIKit and Core Graphics drawing routines you use… Read More »

Custom TableView in iOS Swift

By | August 6, 2016

In this post we will see how we can create custom tableview cells in Swift. Let’s Start… Create a new project and name it the way you like. For creating Custom TableView we have to do below things 1. Drag a tableview and Drag a UITableView Cell into it. 2. For our example – Drag and image and… Read More »

Apple MapKit – Loading Maps, Finding User Location, Searching for a Location, Adding Annotation, Interacting with Annotations, Drawing Lines in Maps, Adding Circle, Showing Route between two locations.

By | July 25, 2016

In this demo we will be doing the following things using Apple MapKit and Google Maps API. Load Maps Add Annotation Search for a Location Decode an Address Find route between locations For starting we will add a MapView to the Storyboard and hook it to a variable named mapView. You can simply run the project and see… Read More »

In-App Purchase in iOS

By | July 20, 2016

In-App purchase is a way of selling digital content from inside the apps. This helps the app developers to sell their apps for free and monetize the app in a clean and efficient way. In-App purchase has been a major source of revenue for Apple and Developers almost similar to Paid Apps. Below are the steps involved in… Read More »

What are optionals in Swift ( ? && ! ).

By | June 30, 2016

Swift introduces Optionals type, which handles the absence of a value. Optionals say if there are set a value, then take that value, it can be of any type AND else it is nil. Basically It has two possible values, None and Some(T), where T is an associated value of the correct data type available in Swift. Example… Read More »

Using NSOperationQueue in iOS to do Serial/Concurrent Operations.

By | May 7, 2016

NSOperationQueue is used to do scheduled operations in iOS. You can customize NSOperationQueue to do Concurrent/Serial operations. You can set NSOperationQueue maxConcurrentOperationCount to tell it to do how many operations to execute at a time. Lets see this with an example [Swift Version] In the above example, we set maxConcurrentOperationCount to 1, telling it to execute one by… Read More »

Solution for CoreData Multithreading problem.

By | May 1, 2016

This post is for people who are at least familiar with CoreData. But just knowing is not everything.. CoreData creates problems when you access them from different threads… Most common problems are listed below CoreData: error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[__NSCFSet… Read More »

ld: warning: directory not found for option -F or -L, Xcode Error – Solved.

By | April 15, 2016

There are two errors like this that often happens with the Xcode. If it is a “directory not found for option ‘-L/…” error, that means it’s a Library Error, then Follow the below steps… Click on your project (targets) Click on Build Settings, Search for “Library Search Paths” Under Library Search Paths, delete the paths and keep the… Read More »

Advantages of NSURLSession over NSURLConnection in iOS and Sample Demo Code

By | March 30, 2016

In an application we usually works with Data tasks – Data tasks are used for requesting data from a server, such as JSON data. These data are usually stored in memory and never touches the File System We can use NSURLSessionDataTask. Upload Tasks – Upload tasks are used to upload data to a remote destination. We can use… Read More »