import xxx from './xxxx'
let test2;
export default class Test extent Componnet {
	getTest2 = ()=>{
		// 对test2模块进行懒加载（延迟加载），以提高性能
		if(test2 === undefined) {
			test2 = require('./xxxx/test2');
		}
	}
}

NSString *obj = [[NSData alloc] init];
NSInteger length = obj. length;
NSString  *testStr = [obj stringApendString....];

-appdelegate：didfinishedLanch ｛
      dispatch_async(globalqueue,^{
             [self  testTimer];
       })
｝
-testTimer {
     NSTimer *timer = [NSTimer  scheduleTimerWith:timerActiom];
}
-timerActiom {
      NSLog(@“timer action”);
}

  
    UIView *greenView = UIView.new;
    greenView.backgroundColor = UIColor.greenColor;
    [self addSubview:greenView];
    UIView *redView = UIView.new;
    redView.backgroundColor = UIColor.redColor;
    [self addSubview:redView];
    UILabel *blueView = UILabel.new;
    blueView.backgroundColor = UIColor.blueColor;
    [self addSubview:blueView];
    UIView *superview = self;
    int padding = 10;
    // 给视图添加key的方式有两种，如下所示
    // 法一：
    //you can attach debug keys to views like so:
    // greenView.mas_key = @"greenView";
    // redView.mas_key = @"redView";
    // blueView.mas_key = @"blueView";
    // superview.mas_key = @"superview";
    // 法二：
    //OR you can attach keys automagically like so:
    MASAttachKeys(greenView, redView, blueView, superview);
    // 给约束添加key
    [blueView mas_makeConstraints:^(MASConstraintMaker *make) {
        //you can also attach debug keys to constaints
        make.edges.equalTo(@1).key(@"ConflictingConstraint"); //composite constraint keys will be indexed
        make.height.greaterThanOrEqualTo(@5000).key(@"ConstantConstraint");
        make.top.equalTo(greenView.mas_bottom).offset(padding);
        make.left.equalTo(superview.mas_left).offset(padding);
        make.bottom.equalTo(superview.mas_bottom).offset(-padding).key(@"BottomConstraint");
        make.right.equalTo(superview.mas_right).offset(-padding);
        make.height.equalTo(greenView.mas_height);
        make.height.equalTo(redView.mas_height).key(@340954); //anything can be a key
    }];
    
    return self;
}

Probably at least one of the constraints in the following list is one you don't want. 
	Try this: 
		(1) look at each constraint and try to figure out which you don't expect; 
		(2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<MASLayoutConstraint:0x6000000a5e20 UILabel:0x7fb318c2c990.left == MASExampleDebuggingView:0x7fb318c15c00.left + 1>",
    "<MASLayoutConstraint:0x6080000a40e0 UILabel:0x7fb318c2c990.left == MASExampleDebuggingView:0x7fb318c15c00.left + 10>"
)

Probably at least one of the constraints in the following list is one you don't want. 
	Try this: 
		(1) look at each constraint and try to figure out which you don't expect; 
		(2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<MASLayoutConstraint:ConflictingConstraint[0] UILabel:blueView.left == MASExampleDebuggingView:superview.left + 1>",
    "<MASLayoutConstraint:0x6000000b7ac0 UILabel:blueView.left == MASExampleDebuggingView:superview.left + 10>"
)

// 当你使用autoLayout布局的时候建议写此方法，防止autoresize布局造成的错误
+ (BOOL)requiresConstraintBasedLayout
{
    return YES;
}
// this is Apple's recommended place for adding/updating constraints
// 苹果推荐添加或者更新（update、remake）约束的地方
- (void)updateConstraints {
    [self.growingButton updateConstraints:^(MASConstraintMaker *make) {
        make.center.equalTo(self);
        make.width.equalTo(@(self.buttonSize.width)).priorityLow();
        make.height.equalTo(@(self.buttonSize.height)).priorityLow();
        make.width.lessThanOrEqualTo(self);
        make.height.lessThanOrEqualTo(self);
    }];
    // according to apple super should be called at end of method
    [super updateConstraints];
}

However Auto Layout does not allow alignment attributes such as left, right, centerY etc to be set to constant values. 
So if you pass a NSNumber for these attributes
 Masonry will turn these into constraints relative to the view’s superview ie:
 [view makeConstraints:^(MASConstraintMaker *make) {    
        make.left.lessThanOrEqualTo(@10)
 }];

// topInnerView的宽度是高度的1/3
[self.topInnerView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.width.equalTo(self.topInnerView.mas_height).multipliedBy(3);
]

 UIView *superview = self;
    int padding = 10;
    //if you want to use Masonry without the mas_ prefix
    //define MAS_SHORTHAND before importing Masonry.h see Masonry iOS Examples-Prefix.pch
    [greenView makeConstraints:^(MASConstraintMaker *make) {
        make.top.greaterThanOrEqualTo(superview.top).offset(padding);
        make.left.equalTo(superview.left).offset(padding);
        make.bottom.equalTo(blueView.top).offset(-padding);
        make.right.equalTo(redView.left).offset(-padding);
        make.width.equalTo(redView).multipliedBy(1);
        make.height.equalTo(redView.height);
        make.height.equalTo(blueView.height);
    }];
    //with is semantic and option
    [redView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(superview.mas_top).with.offset(padding); //with with
        //make.left.equalTo(greenView.mas_right).offset(padding); //without with
        make.bottom.equalTo(blueView.mas_top).offset(-padding);
        make.right.equalTo(superview.mas_right).offset(-padding);
        // make.width.equalTo(greenView).multipliedBy(1);
        
        make.height.equalTo(@[greenView, blueView]); //can pass array of views
    }];
    
    [blueView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.top.equalTo(greenView.mas_bottom).offset(padding);
        make.left.equalTo(superview.mas_left).offset(padding);
        make.bottom.equalTo(superview.mas_bottom).offset(-padding);
        make.right.equalTo(superview.mas_right).offset(-padding);
        make.height.equalTo(@[greenView.mas_height, redView.mas_height]); //can pass array of attributes
    }];
    return self;
}

@implementation MASExampleUpdateView
- (id)init {
    self = [super init];
    if (!self) return nil;
    self.growingButton = [UIButton buttonWithType:UIButtonTypeSystem];
    [self.growingButton setTitle:@"Grow Me!" forState:UIControlStateNormal];
    self.growingButton.layer.borderColor = UIColor.greenColor.CGColor;
    self.growingButton.layer.borderWidth = 3;
    [self.growingButton addTarget:self action:@selector(didTapGrowButton:) forControlEvents:UIControlEventTouchUpInside];
    [self addSubview:self.growingButton];
    self.buttonSize = CGSizeMake(100, 100);
    return self;
}
+ (BOOL)requiresConstraintBasedLayout
{
    return YES;
}
// this is Apple's recommended place for adding/updating constraints
// 苹果推荐添加或或者更新约束的地方
- (void)updateConstraints {
    [self.growingButton updateConstraints:^(MASConstraintMaker *make) {
        make.center.equalTo(self);
        make.width.equalTo(@(self.buttonSize.width)).priorityLow();
        make.height.equalTo(@(self.buttonSize.height)).priorityLow();
        make.width.lessThanOrEqualTo(self);
        make.height.lessThanOrEqualTo(self);
    }];
    
    // according to apple super should be called at end of method
    [super updateConstraints];
}
- (void)didTapGrowButton:(UIButton *)button {
    self.buttonSize = CGSizeMake(self.buttonSize.width * 1.3, self.buttonSize.height * 1.3);
    // tell constraints they need updating
    // 告诉约束系统要更新，系统会调用上面重写的updateConstraints方法
    [self setNeedsUpdateConstraints];
    // update constraints now so we can animate the change,
    // it will be call by system automatically
    // 该方法不必手动调用
    // [self updateConstraintsIfNeeded];
    // 可以用layoutIfNeeded来实现即时更新，还可以添加动画
    [UIView animateWithDuration:0.4 animations:^{
        [self layoutIfNeeded]; // 需要在此处调用layoutIfNeeded方法才能产生动画
    }];
}
@end

# The target name is most likely the name of your project.
target 'MixRNAndIOS' do
  # Your 'node_modules' directory is probably in the root of your project,
  # but if not, adjust the `:path` accordingly
  pod 'React', :path => ‘./MixRNAndIOS/js/node_modules/react-native', :subspecs => [
    'Core',
    'RCTText',
    'RCTNetwork',
    'RCTWebSocket', # needed for debugging
    # Add any other subspecs you want to use in your project
    'RCTImage',
  ]
end

import "ViewController.h"
import "RCTRootView.h"
@interface ViewController ()
@property (nonatomic, strong) NSDictionary *props;
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    self.props =   @{ @"param" : @[
                                @{
                                  @"name" : @"Alex",
                                  @"des": @"hello，我是从原生传递给RN界面的参数"
                                  }
                              ]
                      };
    
    
    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake((self.view.bounds.size.width - 300)/2, 200, 300, 40)];
    [btn setTitle:@"点我进入react native界面" forState:UIControlStateNormal];
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    
    [btn addTarget:self action:@selector(highScoreButtonPressed) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
}
- (void)highScoreButtonPressed{
    NSURL *jsCodeLocation;
    
#ifdef DEBUG
    //开发的时候用，需要打开本地服务器
    jsCodeLocation = [NSURL URLWithString:@"http://localhost:8081/index.ios.bundle?platform=ios"];
#else
    //发布APP的时候用
    jsCodeLocation = [[NSBundle mainBundle] URLForResource:@"index.ios" withExtension:@"jsbundle"];
#endif
    
    RCTRootView *rootView = [[RCTRootView alloc] initWithBundleURL : jsCodeLocation
                                                 moduleName        : @"RNHighScores"
                                                 initialProperties : self.props  //将native数据传送到RN中
                                                 launchOptions     : nil];
    
    rootView.frame = [UIScreen mainScreen].bounds;
    UIViewController *vc = [[UIViewController alloc] init];
    vc.view.backgroundColor = [UIColor redColor];
    [vc.view addSubview:rootView];
    [self presentViewController:vc animated:YES completion:nil];
}

react-native bundle --entry-file ./index.ios.js --bundle-output ./bundle/index.ios.jsbundle --platform ios --assets-dest ./bundle --dev false

jsCodeLocation = [[NSBundle mainBundle] URLForResource:@"index.ios" withExtension:@"jsbundle"];

<Image source={{uri:'happiness.jpg'}} style={styles.happy}/>

typedef void (^Block)(void);
int main(int argc, const char * argv[]) {
//这样声明
Block block = ^{};
//而不是这样
//void(^block)(void)=^{};
return 0;
}

void (^block)();
if(/*some condition*/){
block = ^{
NSLog(@"Block A");
};
}else{
block = ^{
NSLog(@"Block B");
};
}
block();

void (^block)();
if(/*some condition*/){
block = [^{
NSLog(@"Block A");
} copy];
}else{
block = [^{
NSLog(@"Block B");
} copy];
}
block();

@property (copy) Block block; //属性默认就是atomic

Block block  = self.block;
if(block){
block();
}

if(self.block){
//我是其他线程，我要这里要捣乱
block();
}

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
void(^block)(void)=^{
NSLog(@"Block!!");
};
block();
return 0;
}

//block的结构体
struct __main_block_impl_0 {
//block的实现
struct __block_impl impl;
//block的描述（包含block的大小以及copy，dispose等）
struct __main_block_desc_0* Desc;
//block的构造函数，对block结构体成员变量的初始化
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int flags=0) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
//block内的代码实现部分
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
NSLog((NSString *)&__NSConstantStringImpl__var_folders_1q_hr0kg_v15rj7ry_618ljfldr0000gn_T_hellow_a5b27a_mi_0);
}
//block的描述，包含block的大小以及copy，dispose
static struct __main_block_desc_0 {
size_t reserved;
size_t Block_size;
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0)};
//OC中的main函数
int main(int argc, char * argv[]) {
void(*block)(void)=((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA));
((void (*)(__block_impl *))((__block_impl *)block)->FuncPtr)((__block_impl *)block);
return 0;
}

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
//自动变量i
int i = 10;
void(^block)(void)=^{
NSLog(@"Block!!---%d",i);
};
block();
return 0;
}

struct __main_block_impl_0 {
struct __block_impl impl;
struct __main_block_desc_0* Desc;
//这是block捕获的变量
int i; 
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int _i, int flags=0) : i(_i) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
int i = __cself->i; // bound by copy
NSLog((NSString *)&__NSConstantStringImpl__var_folders_1q_hr0kg_v15rj7ry_618ljfldr0000gn_T_main_1b12e5_mi_0,i);
}
static struct __main_block_desc_0 {
size_t reserved;
size_t Block_size;
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0)};
int main(int argc, const char * argv[]) {
int i = 10;
void(*block)(void)=((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, i));
((void (*)(__block_impl *))((__block_impl *)block)->FuncPtr)((__block_impl *)block);
return 0;
}

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
__block int i = 10;
void(^block)(void)=^{
i += 1;
NSLog(@"Block!!---%d",i);
};
block();
return 0;
}

//存储block截获的外围变量的一个结构体
struct __Block_byref_i_0 {
void *__isa;
__Block_byref_i_0 *__forwarding;
int __flags;
int __size;
int i;
};
struct __main_block_impl_0 {
struct __block_impl impl;
struct __main_block_desc_0* Desc;
//这是block捕获的变量
__Block_byref_i_0 *i; // by ref
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_i_0 *_i, int flags=0) : i(_i->__forwarding) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
__Block_byref_i_0 *i = __cself->i; // bound by ref
(i->__forwarding->i) += 1;
NSLog((NSString *)&__NSConstantStringImpl__var_folders_1q_hr0kg_v15rj7ry_618ljfldr0000gn_T_main_10e8d1_mi_0,(i->__forwarding->i));
}
//下面两个指针函数是__main_block_desc_0结构体中的函数指针的实现，前者是要保留block截获的对象，后者则将之释放
static void __main_block_copy_0(struct __main_block_impl_0*dst, struct __main_block_impl_0*src) {_Block_object_assign((void*)&dst->i, (void*)src->i, 8/*BLOCK_FIELD_IS_BYREF*/);}
static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->i, 8/*BLOCK_FIELD_IS_BYREF*/);}
//block的描述
static struct __main_block_desc_0 {
size_t reserved;
size_t Block_size;
void (*copy)(struct __main_block_impl_0*, struct __main_block_impl_0*);
void (*dispose)(struct __main_block_impl_0*);
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0), __main_block_copy_0, __main_block_dispose_0};
//主函数
int main(int argc, const char * argv[]) {
__attribute__((__blocks__(byref))) __Block_byref_i_0 i = {(void*)0,(__Block_byref_i_0 *)&i, 0, sizeof(__Block_byref_i_0), 10};
void(*block)(void)=((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, (__Block_byref_i_0 *)&i, 570425344));
((void (*)(__block_impl *))((__block_impl *)block)->FuncPtr)((__block_impl *)block);
return 0;
}