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반응형 웹디자인, rem 과 em? 1. rem과 em의 공통점? rem과 em은 모두 CCS의 font-size 속성 값에 비례해서 결정되는 상대 단위이다. px은 고정값인데 비해 이는 브라우저에 의해 달리 계산된다. 예를들어 font-size가 20px 이라면 1rem은 20 x 1 px, 0.5rem은 20 x 0.5 px이 된다. 따라서 font-size값에 따라 유동적으로 값을 바꿔주려는 경우 rem이나 em을 사용하면 된다. 2. rem과 em의 차이점? rem과 em 모두 상대단위이지만 어느 font-size를 기준으로 하는지에 따라 차이가 발생한다. rem의 경우 root-em 으로써 최상위 요소의 font-size 즉 태그의 font-size를 기준으로 한다. 반면 em의 경우 em이 쓰..

How to make custom keyboard? When using textField or textView, you may want to show custom keyboard. For example in facebook messanger, it shows two icons instead of key pad. In that case, you can use textfield inputView. 1. Make your custom view You can use storyboard or programmatically make one. 2. Add custom view to textField inputView. 3. Add button click event When button clicked, call bec..

How to change UITextField placeholder color? When you want to change UITextField placeholder color, there are two ways. One way is using code, and the other way is using storyboard. In code) If you want to do it programmatically, you can use attributedString. Replace "Placeholder" with 'real' placeholder and set color what you want. In storyboard) If you want to do it in storyboard, you can use ..

How to add pull to refresh on collectionview? Pull to refresh is often used in lists. It's not hard to add pull to refresh on collectionview. You can use UIRefreshControl to implement it. Set collectionview refreshControl. You can custom refreshControl color by tintColor property, size by scale and you can even set title. And implement selector function. You should call your data refresh functio..

Xcode Mark Lines Xcode Mark Lines allows to create a overview of sections within code. Xcode Mark Lines make it easier to quickly navigate through a relative big object. Xcode Mark Lines are added through commented code. For addition, there are fixme and todo lines. Xcode parses those comments into chapter lines within the method navigator. You could easily found comment in navigator. When you c..

Difference between scene delegate and app delegate From Xcode 11 you might have noticed a new named SceneDelegate.swift. In prior iOS 13, There is only AppDelegate file. AppDelegate is the main entry of the app and handles app states. But from iOS 13, the responsibilites of AppDelegate have been split between AppDelegate and SceneDelegate. This is the for support new multi-window support feature..

How to init keychain when app deleted? Keychain is safe & encrypted way to save small storage data. But data in user defaults is in no way stored securely as hackers can access it pretty easily from the device. Apple has provided the Keychain Services API to deal with this problem. Developers can safely handle passwords and other sensitive information using key chain service api. But unlike user..

Xcode 12 introduced support for using Scalable Vector Graphic (SVG) image assets in iOS, macOS, and iPadOS. Until xcode 12, you were able to use single scale resources by using PDF assets. Note that SVG assets are only supported on macOS 10.15 or later, iOS 13 or later, and iPadOS or later. Using SVG images in Xcode is pretty easy. Just change scales option to Single Scale! Default value is Indi..

How to ignore return value? Sometimes you might want to ignore the return value while in other cases you might use it. In that situation, you can use @discardableResult attribute! Let's see example. When you call update function like below. You will see warning :( You might fix the warning like this. But it's ugly code. In that case, you could use @discardableResult attribute. It will fix warnin..

How to drag and drop collectionView Cell? You can use dragDelegate and dropDelegate! First, set delegate! Second, implement drag method! Note that replace item with your own cell item! Now you can drag your cell! Finally, implement drop method! DropSessionDidUpdate method returns a UICollectionViewDropProposal. This is how we tell the DropDelegate that something is happening when the user drags ..

Error handling in swift Try catch with throw makes error handling nicely in code. let's talk about use cases and code example! 1. Method with throws You can create method with throw easily. Method with throw should call with try catch otherwise you get "Call can throw but is not marked with try" error. 2. Struct initializer with throw You can also use throw with struct init method. This especial..

2020 September, ios14 is released. Today let's talk about major change in ios14 about IDFA(Identifier For Advertisers). Since iOS 14, IDFA will become available only with user consent. What is IDFA? IDFA is UUID-identifier of the device. It is used to track app install sources, run re-marketing ad campaigns etc.. IDFA was introduced in 2016. It replaced Device ID – identifier that was unique for..

How to detect screenshot action? There is no way to prevent user screenshot.. :( For more details. iOS Detection of Screenshot? The app Snapchat, on the App Store, is an app that lets you share pictures with a self-destruct on them. You can only view the pics for X seconds. If you attempt to take a screenshot while the pict... stackoverflow.com

What is Enumeration? An enumeration is a data type consisting of a set of named values, called members. Apple doc says: An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe way within your code. An enumeration can be a string, a character, or integer or floating-point type. How to define enum type? 1. Enum with type definitio..

Introduce UIColorPickerViewController ! UIColorPickerViewController is new feature on iOS 14. Noted it is only available on iOS 14! You can use UIColorPickerViewController like this! UIColorPickerViewController looks like this! You can set default color too. Like other picker, uicolorpickerviewController have delegate too. Happy coding:)