Peter Steinberger steipete

Mobile Safari's 100% Height Dilemma

Whether you're developing a web application with native-ish UI, or just a simple modal popup overlay that covers the viewport, when it comes to making things work on iDevices in Mobile Safari, you're in for a decent amount of pain and suffering. Making something "100% height" is not as easy as it seems.

This post is a collection of Mobile Safari's gotchas and quirks on that topic, some with solutions and fixes, some without, in good parts pulled from various sources across the internets, to have it all in one place. Things discussed here apply to iOS8, iOS9 and iOS10.

The Disappearing Browser Chrome

Screen real estate on smartphones is limited, so Mobile Safari collapses the browser chrome (address bar and optional tab bar at the top, and tool bar at the bottom) when the user scrolls down. When you want to make something span exactly the height of the viewport, or pin something to the bottom of the screen, this can get tricky because the viewport changes size (or

	#import "MyNonClusteredClass.h"

	@interface GenericIsKindOfClass<ObjectType : MyNonClusteredClass *> : NSObject

	+ (instancetype _Nonnull)new NS_UNAVAILABLE;
	- (instancetype _Nonnull)init NS_UNAVAILABLE;
	- (instancetype _Nonnull)initWithInstanceOfObjectType:(ObjectType _Nonnull)instanceOfObjectType NS_DESIGNATED_INITIALIZER;

	- (ObjectType _Nullable)typeSafeDowncastOrNil:(NSObject * _Nonnull)object;

	As of iOS 11/macOS High Sierra, and only including ones in Foundation and CoreFoundation

	Strings:

	_NSCFString - a CFStringRef or CFMutableStringRef. This is the most common type of string object currently.
	- May have 8 bit (ASCII) or 16 bit (UTF-16) backing store
	_NSCFConstantString - a compile time constant CFStringRef, like you'd get with @"foo"
	- May also be generated by dynamic string creation if matches a string in a pre-baked table of common strings called the StringROM
	NSBigMutableString - an NSString backed by a CFStorage (https://github.com/opensource-apple/CF/blob/master/CFStorage.h) for faster handling of very large strings
	NSCheapMutableString - a very limited NSMutableString that allows for zero-copy initialization. Used in NSFileManager for temporarily wrapping stack buffers.

	#import <Foundation/Foundation.h>
	#import <time.h>
	#import <os/lock.h>

	#define ITERS 2000
	#define NSEC_PER_ITER(time) (((double)time * (double)NSEC_PER_SEC) / (double)ITERS)

	#define TEST(body, name) do {\
	start = [NSDate date];\
	for (int i = 0; i < ITERS; i++) {\

	@import Foundation;
	@import CoreGraphics;

	typedef struct __attribute__((objc_boxable)) CGPoint CGPoint;
	typedef struct __attribute__((objc_boxable)) CGSize CGSize;
	typedef struct __attribute__((objc_boxable)) CGRect CGRect;
	typedef struct __attribute__((objc_boxable)) CGVector CGVector;

	int main(int argc, const char * argv[]) {
	@autoreleasepool {

	// Macros for creating NSArray and NSSet objects as replacement for @[…] literal.

	let components = NSArray(street, city, state, country);

	// Advantages:
	// 1. Type of NSArray is inferred, in this case it’s NSArray<NSString >
	// 2. List of objects is type-checked, so mixing types like NSArray(@42, @"Hi") will report compilation error.
	// 3. Ability to allocate any class, not just NSArray. For example NSSet and NSMutableArray.
	// 4. Avoids stupid clang bracket matching bug, if you know what I mean.

	NSDate *date = [NSDate new];

	NSDateFormatter *dateFormatter = [NSDateFormatter new];
	dateFormatter.locale = [NSLocale localeWithLocaleIdentifier:@"nl_NL"];
	dateFormatter.dateStyle = NSDateFormatterFullStyle;
	dateFormatter.formattingContext = NSFormattingContextDynamic; // this is the important setting

	NSString *dateString = [dateFormatter stringFromDate:date];

	NSString *s1 = [NSString stringWithFormat:@"Foo %@", dateString]; // "Foo dinsdag 13 december 2016"

	// Created by Derrick Cohodas (dav-)
	// Based on the Python example by StackExchange user wwnick from http://gis.stackexchange.com/a/415/41129


	// Requires the Mathjs library - http://mathjs.org/
	var math = require('mathjs')

	/**
	* Represents a coordinate with a distance
	* @param {Number} lat Latitude

	import Foundation

	// Swift translation of https://pspdfkit.com/blog/2016/running-ui-tests-with-ludicrous-speed/
	class ConditionTester {
	typealias TestCondition = () -> (Bool)

	private let condition: TestCondition
	private var fulfilled: Bool { return condition() }
	private var currentRunLoop: CFRunLoop {
	return RunLoop.current.getCFRunLoop()

	<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
	<!-- iOS 10, macOS Sierra, and friends bring a new logging subsystem that's
	supposed to scale from the kernel, up to frameworks, and up to apps. It defaults
	to a more regimented, privacy-focused approach that large apps and complex
	systems need.

	It, along with Activity Tracing introduced in iOS 8 and macOS Yosemite and the
	Console app in macOS Sierra, hope to help you graduate from caveman debugging to