diff --git a/Chapter1 - iOS/1.1.md b/Chapter1 - iOS/1.1.md
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+# Image Assets Optimization for Project Size
+
+> A small iOS project with many features can grow large in size. Under an Xcode project, image assets can take up a lot of space, and if an app needs a one-click skin/theme change, imagine how many images that requires. Each set of images also needs 1x, 2x, 3x, etc.
+
+## Introduction
+
+IconFont technology originated in the web field from Web Font technology. Over time, web design became more beautiful. But system-installed fonts on computers could no longer satisfy designers, so Web Font technology was born. An English character font set is not large; by downloading fonts over the network, webpages can be rendered. With Web Font technology, designers gained much more freedom.
+
+In web design, icons need to adapt to multiple resolutions, and each icon would require a separate network request. Someone thought to use the Web Font approach to solve both problems: make vector icons into a font, so a single network request suffices and the icons scale cleanly. Another way to solve this is using sprite images.
+
+The web community has used IconFont-like techniques for years—when I first encountered Bootstrap in 2015, Font Awesome was very popular. Recently IconFont technology has been applied to iOS image assets. I had some time to research and整理 (organize) it, and I record my learning here.
+
+## Advantages
+
+* Reduce size — font files are smaller than images
+* Icon fidelity when scaling — solves 2x/3x and future n× image issues
+* Easy to change color and size, image reuse
+
+## Disadvantages
+
+* Only suitable for
+  `single-color icons`
+* Using Unicode characters is hard to understand
+* Need to maintain the font library
+
+There are many tutorials online about how to make IconFonts; I won't discuss that here.
+
+## How to use
+
+1. First pick some rich resource sites. I've used Alibaba's IconFont for years and didn't research others, so I'll use Alibaba's product here. Address: http://www.iconfont.cn/plus
+
+2. Open the site and select suitable icons into the cart, as shown:
+![](../assets/2017-05-28-iconfontPickUp.png)
+
+3. After selecting, view the cart and click to download the code.
+
+4. Open the downloaded file; its structure is as follows. In iOS development we use the Unicode form of IconFont, so open demo_unicode.html
+![Downloaded file structure](../assets/2017-05-28-iconfontWorkDirectory.png)
+
+**Note:** Create UIFont using the font's PostScript name, not the file name; text values are 8-digit Unicode characters. We can open demo.html to find the HTML entity Unicode code for each icon. For example: the icon "店" corresponds to HTML entity Unicode code: 0x3439. Converted it becomes: \U00003439 — replace 0x with \U and pad with zeros to reach 8 characters.
+
+# Using IconFont in Xcode
+
+Initial attempt usage
+
+1. First see how to use IconFont simply.
+2. Add the downloaded **iconfont.ttf** into the Xcode project and ensure it's included in Build settings.
+
+![Xcode inclusion check](../assets/2017-05-28-iconfintWorkSetting.png)
+
+3. How to use?
+
+```objective-c
+NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc] initWithString:@"\U0000e696  \U0000e6ab  \U0000e6ac  \U0000e6ae"];
+[attributedStr addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0, 1)];
+[attributedStr addAttribute:NSForegroundColorAttributeName value:[UIColor orangeColor] range:NSMakeRange(3, 1)];
+[attributedStr addAttribute:NSForegroundColorAttributeName value:[UIColor blackColor] range:NSMakeRange(9, 1)];
+self.label.attributedText = attributedStr;
+[self.view addSubview:self.label];
+
+#pragma mark - getter and setter
+-(UILabel *)label{
+       if (!_label) {
+           _label = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, BoundWidth-200, 40)];
+           _label.font = [UIFont fontWithName:@"iconfont" size:24];
+           _label.textColor = [UIColor purpleColor];
+       }
+       return _label;
+   }
+```
+
+#### Further encapsulation for easier use
+
+Generating a UIImage from IconFont only requires LBPIconFontmake(par1, par2, par3), where par1: the iconfont Unicode value; par2: image size; par3: image color. LBPIconFontmake is a macro: #define LBPIconFontmake(text,size,color) [[LBPFontInfo alloc] initWithText:text withSize:size andColor:color].
+
+```objective-c
+self.latestImageView.image = [UIImage iconWithInfo:LBPIconFontmake(@"\U0000e6ac", 60, @"000066") ];
+```
+![Encapsulated project structure](../assets//2017-05-28-iconfont.png)
+
+1. LBPFontInfo encapsulates font information.
+2. UIColor+picker sets color from a hex string.
+3. LBPIconFont registers the IconFont into the system and uses it.
+4. UIImage+LBPIconFont provides a UIImage category for using IconFont.
+
+# Demo repository
+
+https://github.com/FantasticLBP/IconFont_Demo
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diff --git a/Chapter1 - iOS/1.2.md b/Chapter1 - iOS/1.2.md
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+# Understanding Initializers
+
+## Initializers
+
+* The internal implementation of the new method is to call alloc first, then call init.
+  * alloc: Sends the alloc message to a class; alloc returns an instance of that class.
+  * init: An instance method whose role is to initialize the object.
+* Steps to create an object: first use alloc to create an object, then use init to initialize it before using the object.
+  * Using an uninitialized object is dangerous.
+* init method: Purpose — initialize the object and set initial values; this is called a constructor (initializer).
+
+## Overriding init
+
+* If you want the created object's properties to have values other than the default initialization values, you need to override init.
+* Rules for overriding init:
+  * You must first call the superclass's init method (because initialization of the current class proceeds through [super init]), and assign the returned value to self.
+  * Calling init may fail; if it fails, return nil.
+  * Check whether the superclass initialized successfully. If self != nil, initialization succeeded.
+  * If initialization succeeded, initialize the current class's properties.
+  * Finally return self.
+
+#### Clarifications:
+
+1. Why call the superclass init method?
+   1. The current object has an isa pointer; the isa pointer is set through the superclass's init.
+   2. You need to ensure that the superclass's properties are also initialized.
+2. Pattern for overriding init:
+
+```
+-(instancetype)init{
+    if (self = [super init]) {
+        // todo: custom property initialization
+    }
+    return self;
+}
+```
+
+```objc
+// Person
+
+#import <Foundation/Foundation.h>
+
+@interface Person : NSObject
+@property NSString* name;
+@property int age;
+
+-(void)sayHi;
+
+@end
+
+#import "Person.h"
+@implementation Person
+
+-(void)sayHi{
+    NSLog(@"Hi");
+}
+
+-(instancetype)init{
+    self = [super init];
+    if (self) {
+        self.name = @"杭城小刘";
+        self.age = 22;
+    }
+    return self;
+}
+@end
+
+
+// Test
+
+ Person *p1 = [[Person alloc] init];    // p1.name = "杭城小刘", p1.age = 22;
+ Person *p2 = [Person new];             // p2.name = "杭城小刘", p2.age = 22;
+```
+
+If two classes have a composition relationship and one property is an object of another class, that property defaults to nil when the containing class is initialized. How to initialize it?
+
+```
+-(instancetype)init{
+    self = [super init];
+    if (self) {
+        self.name = @"lbp";
+        self.age = 22;
+        self.pig = [[Pig alloc] init];
+    }
+    return self;
+}
+
+// Test
+  Person *p1 = [[Person alloc] init];        // p1.pig != nil
+```
+
+## Custom initializers
+
+* Current situation: Although each created object's properties are not the default values, every initialized object has the same values.
+* Requirement: Allow callers to decide the property values when instantiating.
+* Solution: Custom initializer.
+* Rules for custom initializers:
+  * The return type should be instancetype.
+  * The method name must begin with initWith.
+  * The implementation is similar to init.
+* Note: You cannot use new to call a custom initializer. (new performs alloc then init; default init assigns the default property values.)
+
+```
+-(instancetype)initWithName:(NSString *)name andAge:(int)age{
+    if (self = [super init]) {
+        self.name = name;
+        self.age = age;
+    }
+    return self;
+}
+```
+
+```objc
+// Person
+#import <Foundation/Foundation.h>
+@interface Person : NSObject
+@property NSString* name;
+@property int age;
+
+-(instancetype)initWithName:(NSString *)name andAge:(int)age;
+@end
+
+#import "Person.h"
+@implementation Person
+
+-(instancetype)init{
+    self = [super init];
+    if (self) {
+        self.name = @"lbp";
+        self.age = 22;
+    }
+    return self;
+}
+
+// You cannot assign to self outside of an initializer.
+// The compiler treats only methods starting with initWith as initializers.
+
+-(instancetype)initWithName:(NSString *)name andAge:(int)age{
+    if (self = [super init]) {
+        self.name = name;
+        self.age = age;
+    }
+    return self;
+}
+
+@end
+
+
+// Test
+Person *p1 = [[Person alloc] init];
+Person *p2 = [Person new];    
+Person *p3 = [[Person alloc] initWithName:@"杭城小刘2号" andAge:23];
+```
+
+![init](../assets/2017-05-23-5-56-53.png)
+![init](../assets/2017-05-23-5-57-08.png)
+
+
+An experiment about "custom initializers must start with initWith"
+
+![initwith](../assets/2017-05-23-6-01-29.png)
+
+The error message is clear: you cannot assign to self outside of an initializer.
+
+Because the compiler considers only methods starting with initWith as initializers.
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diff --git a/Chapter1 - iOS/1.3.md b/Chapter1 - iOS/1.3.md
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+# loadView
+
+1. Purpose: load the controller's view
+2. When it's called: it's called the first time the controller's view is used
+3. Use case: implement this method when you want to provide a custom view for the controller
+
+Accessing the controller's view is equivalent to calling the controller's view getter:
+```objective-c
+-(UIView *)view
+{
+    if(_view == nil){
+        [self loadView];
+        [self viewDidLoad];
+    }
+    return _view;
+}
+```
+
+# Controller view loading flow
+![Controller view loading flow](../assets/2287777-b6128646373dfffb.png)
+
+- The controller's `init` method internally calls `initWithNibName`
+
+  `MyViewController *vc = [[MyViewController alloc] init];`
+
+Notes:
+
+The system's decision logic assumes: no nibName specified; no custom loadView method; the controller is named ...Controller
+
+Decision rules:
+
+- Check whether a nibName was specified; if specified, load that nib
+- Check whether there's an xib with the same name as the controller but without "Controller" in its name; if present, load it
+- If the previous step doesn't find one, check whether an xib with the same name as the controller class exists; if present, load it
+- If no xib describes the controller's view, do not load any xib
+
+## How MyViewController loads its view
+
+- Check whether an xibName was specified; if so, load the specified xib
+- Check whether there's an xib with the same name as the controller class but without "Controller" in the name
+- Check whether there's an xib with the same name as the controller class; if present, load it
+- Otherwise, create an empty view directly
+
+Example
+
+```objective-c
+// in AppDelegate
+ViewController *vc = [[ViewController alloc] init];
+vc.view.backgroundColkor = [UIColor redColor];
+self.window.rootViewController = vc;
+[pself.window makeKeyAndVisable];
+
+// ViewController
+-(UIView *)view{
+    if(!_view){
+        [self loadView];
+        [self viewDidLoad];
+    }
+}
+
+-(void)loadView{
+    UIView*view = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];
+    view.backgroundColor = [UIColor greenColor];
+    self.view = view;
+}
+
+-(void)viewDidload{
+    [super viewDidload];
+    self.view.backgroundColor = [UIColor brownColor];
+}
+```
+
+### What color will the interface be at this point?
+
+Many people might answer "green." Actually, the answer is red.
+
+Why? In AppDelegate, `vc.view.backgroundColor` calls vc's view getter. Inside the getter it checks if `_view` exists; if not, it creates a new UIView by calling `[self loadView]`. After creating the view it calls `viewDidLoad`; if the view already exists it returns it directly. So the sequence is: first green, then brown, and finally red.
+
+#### An official explanation
+
+![Apple documentation](../assets/2287777-8ff7c3b976ffb29a.png)
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diff --git a/Chapter1 - iOS/chapter1.md b/Chapter1 - iOS/chapter1.md
index b5be711..a7e37fe 100644
--- a/Chapter1 - iOS/chapter1.md	
+++ b/Chapter1 - iOS/chapter1.md	
@@ -119,7 +119,7 @@ Part One mainly introduces problems encountered or interesting knowledge in iOS
   * [114. Swift optimizations](1.114.md)
   * [115. AI empowerment on the endpoint](1.115.md)
   * [116. Deep dive into Swift classes](1.116.md)
-  * [117. Swift protocol exploration](1.117.md]
+  * [117. Swift protocol exploration](1.117.md)
   * [118. Swift error handling](1.118.md)
   * [119. Analyze Swift String](1.119.md)
   * [120. Swift access control](1.120.md)
@@ -127,7 +127,16 @@ Part One mainly introduces problems encountered or interesting knowledge in iOS
   * [122. Swift literal fundamentals](1.122.md)
   * [123. Swift pattern matching](1.123.md)
   * [128. SwiftUI research](1.128.md)
-
+  * [129. Swift Dictionary](1.129.md)
+  * [130. GCD](1.130.md)
+  * [131. Package management tools](1.131.md)
+  * [132. Dynamic debugging](1.132.md)
+  * [133. Using PGO in the compiler to optimize app performance](1.133.md)
+  * [134. Removing dead code](1.134.md)
+  * [135. Framework design](1.135.md)
+  * [136. Engineering practices](1.136.md)
+  * [137. Quality testing](1.137.md)
+  * [138. AFNetworking source code walkthrough](1.138.md)
   * [139. Graphics rendering techniques](1.139.md)
   * [140. Aspects](1.140.md)
   * [143. AI empowerment on the endpoint](1.143.md)